How to use TM1637 chip for LED Display?

**Balachandar** · - 10th October 2018, 13:08

Hi All,

For the past 10 days, I have been trying to make the TM1637 work with PBP 2.60C but till now I have not been successful. It's a real low cost module. The price of the TM1637 4-digit 7-segment 0.36" display module is about $ 0.60 in Ali Express. There is a 0.56" version and that costs about $ 1.25.
The module works fine with Arduino, but all the important instructions to interface with TM1637 are in the library file (TM1637Display.h). After spending some time with the library file, I decided to study the datasheet of the chip and write the required code in PBP. The protocol followed by the chip is very similar to I2C with a few differences. Like I2C, it's a two-wire interface but you can have only one slave on the bus and hence there is no slave address. Secondly, while transmitting a byte, the LS bit is sent first.

The code I wrote for PIC 12F1840 is shown below and it is extremely simple. It should make the number '2' appear on the leftmost digit of the display. When I tested the code, the diagnostic LED blinked, but after that nothing happened. I used Saleae Logic Analyzer to check whether the Clock & Data pulses and Ack were all OK. After some tweaking, I managed to get everything correct (Screenshot file attached). The only issue is, the display shows nothing! Since I know that the module is working fine with Arduino, it's my code in PBP that needs to be looked into.

I would highly appreciate any helpful hint, suggestion or sample code.

- Bala

'---------------------------------------------------------------------------
' This code is for using TM1637 with Four-digit 7-segment LED Display
' with PIC12F1840. Osc is set at 16MHz.
'---------------------------------------------------------------------------
'---------------------------------------------------------------------------
'12F1840 Pinout:
' -------------------------------------------------------
' VDD VSS
' PortA.5 = Not_used PortA.0 = LED
' PortA.4 = Not_used PortA.1 = DIO
' PortA.3 = Not_used PortA.2 = CLK
' -------------------------------------------------------

'@ __CONFIG _CONFIG1, _FOSC_INTOSC & _WDTE_ON & _PWRTE_ON & _MCLRE_OFF & _BOREN_OFF
'@ __CONFIG _CONFIG2, _PLLEN_OFF & _BORV_LO & _LVP_OFF

ASM
ifndef __12F1840
error "12F1840 not selected"
endif
ENDASM

OSCCON = %01111000 '16MHz HF, software PLL disabled
DEFINE OSC 16

'Port direction
TRISA = %001000 'A.3 is input, rest are outputs.

CM1CON0 = 0 'Disable comparator
ANSELA = 0 'Disable A to D

'List of Aliases
LED var PortA.0
DIO var PortA.1
CLK var PortA.2
TrisDIO VAR TrisA.1

'List of variables
Cnt var byte
ByteToSend var byte 'Command or Data byte to be sent

DispCmd var byte
dispcmd = 64 'Command byte for displaying characters starting with the leftmost digit (0b01000000)

Brt8Cmd var byte
brt8cmd = 143 'Command byte for display on with maximum brightness (0b10001111)

Dig1Addr var byte
dig1addr = 192 'Address of digit 1 (left most) (0b11000000)

DispNum var byte
dispnum = 146 ' "2" (Common anode) (10010010)

'Diagnostic routine
DiagRoutine:
for cnt = 1 to 4 'Blink LED 4 times.
led = 1 : pause 100
led = 0 : pause 100
next cnt

goto start

'Subroutines
StartCondition:
clk = 0
dio = 1
clk = 1
pauseus 50
dio = 0 'DIO goes low when CLK is high.
pauseus 50
return

SendTheByte:
clk = 0
for cnt = 7 to 0 step -1 'Send 8 bits of data, starting with the LSB.
dio = bytetosend.0(cnt)
pauseus 50
clk = 1
pauseus 50
clk = 0
Next cnt
'dio = 1
Trisdio = 1 ' Set Data pin direction to input to receive ACK.
pauseus 50
clk = 1
pauseus 50
clk = 0
Trisdio = 0 ' Set Data pin direction back to output.
return

StopCondition:
clk = 0
dio = 0
clk = 1
pauseus 50
dio = 1 'DIO goes high when CLK is high.
pauseus 50
return

START:

bytetosend = brt8cmd 'Brt8Cmd (10001111) (143) = Command for Display On with Maximum Brightness
gosub startcondition
gosub sendthebyte
gosub stopcondition

bytetosend = dispcmd 'DispCmd (01000000) (64) = Command byte with auto increment sent before sending the digit data
gosub startcondition
gosub sendthebyte
gosub stopcondition

bytetosend = dig1addr 'Dig1Addr (11000000) (192) = Address of digit 1 (leftmost digit)
gosub startcondition
gosub sendthebyte

bytetosend = dispnum ' Number "2" (10010010) (146) (Common anode)
gosub sendthebyte

gosub stopcondition

END

**mpgmike** · - 10th October 2018, 14:12

Don't know much about your TM1637, but the one thing that jumped out for me was:

Code:

for cnt = 7 to 0 step -1 'Send 8 bits of data, starting with the LSB. 
dio = bytetosend.0(cnt)

I think your FOR/NEXT would be shifting MSB first (bit7, bit6, bit5...)

If you're getting bits banging out, maybe I'm wrong, but try:

Code:

for cnt = 0 to 7
dio = bytetosend.(cnt)

Haven't tried that code, not even in simulation.

**richard** · - 10th October 2018, 14:39

Mike is correct
try this , it works on a 12f1822
note leds 2,3 and 4 show random crap since nothing is written to them
and not using lat regs is asking for trouble

nearly forgot dispnum = 146 ' "2" (Common anode) (10010010)
not on my display

dispnum = $5b ' "2" (Common anode) (01011101)

Code:

OSCCON = %01111000 '16MHz HF, software PLL disabled
 DEFINE OSC 16

 'Port direction
 TRISA = %001000 'A.3 is input, rest are outputs.

 CM1CON0 = 0 'Disable comparator
 ANSELA = 0 'Disable A to D

 'List of Aliases
 LED var PortA.0
 DIO var LATA.1
 CLK var LATA.2 
 TrisDIO VAR TrisA.1

 'List of variables
 Cnt var byte
 ByteToSend var byte 'Command or Data byte to be sent

 DispCmd var byte
 dispcmd = 64 'Command byte for displaying characters starting with the leftmost digit (0b01000000)

 Brt8Cmd var byte
 brt8cmd = 143 'Command byte for display on with maximum brightness (0b10001111)

 Dig1Addr var byte
 dig1addr = 192 'Address of digit 1 (left most) (0b11000000)

 DispNum var byte
 dispnum = $5B' "2" (Common anode) (10010010)

 'Diagnostic routine
 DiagRoutine: 
 CLK=1
 for cnt = 1 to 4 'Blink LED 4 times.
 led = 1 : pause 100 
 led = 0 : pause 100
 next cnt

 goto start

 'Subroutines
 StartCondition:
 clk = 0
 dio = 1
 clk = 1
 pauseus 50
 dio = 0 'DIO goes low when CLK is high.
 pauseus 50
 return

 SendTheByte:
 clk = 0
 for cnt = 0 to 7   'Send 8 bits of data, starting with the LSB. 
dio = bytetosend.0(cnt)
pauseus 50
clk = 1 
pauseus 50
clk = 0
 Next cnt
 'dio = 1 
 Trisdio = 1 ' Set Data pin direction to input to receive ACK.
 pauseus 50
 clk = 1
 pauseus 50
 clk = 0
 Trisdio = 0 ' Set Data pin direction back to output.
 return

 StopCondition:
 clk = 0
 dio = 0
 clk = 1
 pauseus 50
 dio = 1 'DIO goes high when CLK is high. 
 pauseus 50
 return

 START:



 bytetosend = dispcmd 'DispCmd (01000000) (64) = Command byte with auto increment sent before sending the digit data
 gosub startcondition
 gosub sendthebyte 
 gosub stopcondition

 bytetosend = dig1addr 'Dig1Addr (11000000) (192) = Address of digit 1 (leftmost digit)
 gosub startcondition
 gosub sendthebyte

 bytetosend = dispnum ' Number "2" (10010010) (146) (Common anode) 
 gosub sendthebyte

 gosub stopcondition
   bytetosend = brt8cmd 'Brt8Cmd (10001111) (143) = Command for Display On with Maximum Brightness
 gosub startcondition
 gosub sendthebyte
 gosub stopcondition

 END

**Balachandar** · - 11th October 2018, 05:57

Mpgmike & Richard, thanks a lot for your comments and suggestions.

I first tried 'FOR Cnt = 0 to 7'. Since that didn't work, I changed the code to ''FOR Cnt = 7 to 0 STEP -1' to see whether that would make a difference; still the display wouldn't turn on. I agree; if the LSB is to be sent first, it should be 'FOR Cnt = 0 to 7'.

Richard, you are saying, not using LAT registers is asking for trouble. But since the bits for PortA 0, 1 & 2 are cleared in the TRIS register, they have been clearly defined as outputs right in the beginning of the code. Would it make any difference, whether you call it PortA.1 or LATA.1? Are you not referring to the Output in either case? Secondly, referring to the output as LAT results in compilation errors in PBP 2.60C for older PICs like 12F683.

I corrected the code as per the suggestions given, but the display does not turn on. I also tried the same code with a 12F683 at 8MHz IntOsc. Again, there is no good news to report.

In the absence of any working PBP code for TM1637, my only option seems to be that I need to do an in-depth study of the Arduino library files and get a clear understanding to be able to write a working PBP code.

**richard** · - 11th October 2018, 06:41

In the absence of any working PBP code for TM1637, my only option seems to be that I need to do an in-depth study of the Arduino library files and get a clear understanding to be able to write a working PBP code.

the corrected version of your code I posted works for me

the code I posted here works
http://www.picbasic.co.uk/forum/showthread.php?t=23417

sheldons code posted here works

http://www.picbasic.co.uk/forum/showthread.php?t=23974

your code is a bit glitchy and about 30 times too slow but it can work

see difference in these pics

**richard** · - 11th October 2018, 06:45

Richard, you are saying, not using LAT registers is asking for trouble. But since the bits for PortA 0, 1 & 2 are cleared in the TRIS register, they have been clearly defined as outputs right in the beginning of the code. Would it make any difference, whether you call it PortA.1 or LATA.1? Are you not referring to the Output in either case? Secondly, referring to the output as LAT results in compilation errors in PBP 2.60C for older PICs like 12F683.

its all about rmw errors , 12f683 has no lat regs

https://www.microchip.com/webinars.m...cName=en556253

**Balachandar** · - 16th October 2018, 14:05

Thank you Richard, for the clarity you provided on LAT registers.
Couple of days back, I downloaded PBP 3.1.1 with the idea of trying it out and to compile codes written for Ver 3 and above.
I used your demo code (TM1637-DEMO.pbp.txt), made suitable changes for PIC 18F2620 at 32MHz, configured PortB pins 0, 6 & 7 for LED, DIO & CLK respectively and made the required changes in the ASM section for the same. But on compiling, many errors are reported like "Illegal opcode (FSR0)" and "Found label after column 1".
Attached is my code and the screenshot showing the compilation errors. I am clueless as to where the issue is and your help is appreciated.

Code:

define      OSC 32    ' (8 x 4 = 32)

; --- *** Oscillator  *** ---------------------------------------------------

OSCCON = %01110000      'Int Osc: 8MHz 
                        '(Bits 4, 5 & 6 determine the internal clock speed). 
                        ' 111 = 8MHz   110 = 4MHz
'OSCTUNE = %10000000   'PLL is disabled.
OSCTUNE = %11000000   'PLL is enabled.

TRISA = 0
TRISB = 0
TRISC = 0
 
CMCON = 7          'Disable the comparators of PortA
ADCON0 = 0         'Disable ADC
ADCON1 = 15        'All pins of Port A are digital I/O
'    ANSELb = 0
'    ANSELA = 0
'    ANSELC = 0

    LED    VAR  PORTB.0  ' Assign name "LED" to 
         
    USERCOMMAND "DISPLED"    ; BUFFER{,COLON }
    USERCOMMAND "STRLEN"     ; BUFFER
    USERCOMMAND "RJUSTBUFF"  ; BUFFER
    
    TM_BIT        VAR BYTE BANK0
    TM_DAT        VAR BYTE BANK0
    TM_NAK        VAR BYTE BANK0       ;set to $80 if tx error occured
    TM_DIG        VAR BYTE BANK0
    TM_BRIGHT     VAR BYTE BANK0       ;display pwm level 0 to 7
    TM_COLON      VAR BYTE BANK0       ;display colon  0/1
    TM_TMP        VAR BYTE[2] BANK0
    str_len       VAR BYTE BANK0
    
    CMD_AUTO_ADDR CON $40 
    START_ADDR    CON $c0 
    NUM_DIGITS    CON 4                ;number of 7seg leds
    COLON_FLAG    CON $80 
    DISPLAY_ON    CON $88
    ;tm1637      DIO AND CLK NEED TO BE ON SAME PORT
    @TM_OUT_PORT = LATB       ;TM_DIO  OUT
    @TM_IN_PORT  = PORTB      ;TM_DIO  IN
    @TM_CLK      = 6          ;PIN
    @TM_DIO      = 7          ;PIN
    @TM_TRIS     = TRISB 
    
    BLINK         VAR BYTE
    LEDBUFF       VAR BYTE[NUM_DIGITS +1] 
    COUNTER       VAR byte
    
GOTO OVERASM
  
ASM  
DISPLED?B  macro BUFFER       
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    L?CALL _TM_DISP4 
    endm  
DISPLED?BC  macro BUFFER ,COLON      
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    MOVE?CB COLON ,_TM_COLON 
    L?CALL _TM_DISP4 
    endm    
DISPLED?BB  macro BUFFER ,COLON      
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    MOVE?BB COLON ,_TM_COLON 
    L?CALL _TM_DISP4 
    endm 

STRLEN?B  macro BUF      
    MOVE?CB high BUF, FSR0H ;load highbyte 
    MOVE?CB low  BUF, FSR0L ;load low byte
    L?CALL   STRlen
    endm
RJUSTBUFF?B  macro BUF      
    MOVE?CB high BUF, FSR0H ;load highbyte 
    MOVE?CB low  BUF, FSR0L ;load low byte
    MOVE?CB low  BUF, _TM_TMP  ;load low byte
    MOVE?CB HIGH  BUF, _TM_TMP+1  ;load low byte
    L?CALL  STRlen
    L?CALL  _strpad
    endm  
    
           
STRlen                     ;get buffer usage size 
    CLRF     _str_len    
str_tok_chr 
    MOVIW    FSR0 ++       ; Get character
    btfsC    STATUS,Z     
    goto     exit_str_null ; EXIT ON Null char
    INCF     _str_len,F    ; not null so increment index
    goto     str_tok_chr
exit_str_null
    return 

_strpad           ;right justify by padding with spaces " "
    BANKSEL _str_len 
    movlw   _NUM_DIGITS+1     ;buffer size   
    subwf   _str_len,f        ;tx string size
    comf    _str_len,f        ;the difference is number of spaces to SHIFT in
    btfsc   STATUS, Z
    goto    expd              ;if zero difference then exit
nxpd
    movf    _TM_TMP,w         ;addr of buffer l
    MOVWF   FSR0
    movf    _TM_TMP+1,w       ;addr of buffer h
    MOVWF   FSR0+1
	movlw   _NUM_DIGITS         
    addwf   FSR0,f
    movf    FSR0,w
    movwf   FSR1
    movf    FSR0+1,w
    movwf   FSR1+1
    DECF    FSR0,F             ;offset pointer 0
    BANKSEL _TM_BIT
    movlw   _NUM_DIGITS        
    movwf   _TM_BIT
nxby                          ;buffer shift right x 1
    MOVIW   FSR0 --
    MOVWI   FSR1 --
    DECFSZ  _TM_BIT,F
    GOTO    nxby
    movlw   0x20
    MOVWI   FSR1 --            ;poke a space in buff[0]
    BANKSEL _str_len 
    DECFSZ  _str_len,F         ;need another one ?
    goto    nxpd
expd                           ;nah!
    return

  
SEG_val
    CHK?RP  _TM_TMP
    MOVWF   _TM_TMP
    SUBLW   0x21
    btfsc   STATUS, C
    retlw   0   ;" "
    MOVF    _TM_TMP,W
    SUBLW   0x2f
    btfsc   STATUS, C
    retlw   64   ;"-"
    MOVF    _TM_TMP,W
    MOVLW   0X40
    SUBWF   _TM_TMP,W
    btfsC   STATUS, C
    GOTO    TM_ALPHA
    MOVF    _TM_TMP,W
    ANDLW   0X0F
    GOTO    TM_LU
TM_ALPHA 
    ANDLW   0xdf    ;ucase
    SUBLW   6
    btfsS   STATUS, C
    retlw   0       ;ERROR
    MOVLW   0X37
    SUBWF   _TM_TMP,W
    ANDLW   0xdf    ;ucase
TM_LU     
    BRW                                         
    retlw 	0X3F    ;0   
    retlw 	6            	
    retlw 	0X5B   
    retlw 	0X4F 
    retlw 	0X66
    retlw 	0X6D                        
    retlw 	0X7D  
    retlw 	7   
    retlw 	0X7F          
    retlw 	0X67    ;9
    retlw 	0X77    ;A
    retlw 	0X7C    ;b
    retlw 	0X39    ;C
    retlw 	0X5E    ;d
    retlw 	0X79    ;E
    retlw 	0X71    ;F
    
TM_START    
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK
    BSF    TM_OUT_PORT,TM_DIO
    NOP
    BCF    TM_OUT_PORT,TM_DIO
    NOP
    BCF    TM_OUT_PORT,TM_CLK
    NOP
    RETURN
    
TM_STOP 
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    BCF    TM_OUT_PORT,TM_DIO 
    NOP
    BSF    TM_OUT_PORT,TM_CLK 
    NOP
    BSF    TM_OUT_PORT,TM_DIO 
    NOP
    RETURN
    
TM_WRITE 
    MOVLW  8 
    CHK?RP _TM_BIT
    MOVWF  _TM_BIT
NXBT   
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP _TM_DAT
    BTFSS  _TM_DAT,0
    GOTO   TM_0
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_DIO 
    GOTO   TM_NB
TM_0    
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_DIO  
TM_NB   
    CHK?RP _TM_DAT
    RRF    _TM_DAT,F
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK 
    CHK?RP _TM_BIT
    DECFSZ _TM_BIT,F
    GOTO   NXBT
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP TM_TRIS
    BSF    TM_TRIS,TM_DIO 
    CHK?RP TM_IN_PORT
    BTFSC  TM_IN_PORT,TM_DIO 
    BSF    _TM_NAK,7
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK 
    NOP
    NOP
    NOP
    NOP
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP TM_TRIS 
    BCF    TM_TRIS ,TM_DIO 
    RST?RP
    RETURN
_TM_INIT
    CHK?RP  _TM_COLON
    CLRF    _TM_COLON
    CLRF    _TM_BRIGHT
    CHK?RP TM_TRIS
    BCF    TM_TRIS ,TM_DIO
    BCF    TM_TRIS ,TM_CLK
    RST?RP
    RETURN
    
_TM_DISP4 
    MOVLW   _CMD_AUTO_ADDR
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CLRF    _TM_NAK
    CALL    TM_START
    CALL    TM_WRITE
    CALL    TM_STOP
    MOVLW   _NUM_DIGITS          
    CHK?RP  _TM_DIG
    MOVWF   _TM_DIG
    MOVLW   _START_ADDR
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CALL    TM_START
    CALL    TM_WRITE 
NXDIG
    MOVIW   FSR0 ++
    CALL    SEG_val
    CHK?RP  _TM_DAT
    IORWF   _TM_COLON ,W
    movwf   _TM_DAT
    CALL    TM_WRITE
    CHK?RP  _TM_DIG
    DECFSZ  _TM_DIG,F
    GOTO    NXDIG
    CALL    TM_STOP
    CHK?RP  _TM_BRIGHT 
    MOVF    _TM_BRIGHT ,W
    ANDLW   7
    IORLW   _DISPLAY_ON
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CALL    TM_START
    CALL    TM_WRITE
    CALL    TM_STOP
    RST?RP
    RETURN
ENDASM  

OVERASM: 
 
    CALL TM_INIT
    
    
 ALOOP:   
    TOGGLE LED  
    TM_BRIGHT=TM_BRIGHT-1
    if TM_BRIGHT>7 then TM_BRIGHT=7
    ARRAYWRITE LEDBUFF ,["b- ",#TM_BRIGHT,0]
    DISPLED  LEDBUFF,0
    PAUSE 500
    FOR COUNTER=0 TO 255
        ARRAYWRITE LEDBUFF ,[hex COUNTER,0]
        RJUSTBUFF  LEDBUFF 
        DISPLED  LEDBUFF,BLINK
        PAUSE 50
    NEXT
    FOR COUNTER=0 TO 255
        IF  !(COUNTER//20) THEN BLINK = TM_COLON ^ $80
        ARRAYWRITE LEDBUFF ,[sdec COUNTER,0]
        RJUSTBUFF  LEDBUFF 
        DISPLED  LEDBUFF,BLINK
        PAUSE 50
    NEXT
    goto ALOOP

Screenshot showing errors:
Name: AsmErrors.jpg
Views: 4287
Size: 169.2 KB

**richard** · - 16th October 2018, 22:50

MY code is for a pic16 with enhanced core it needs some changes to operate on older chips and/or pic18

moviw fsrx ++ can be replaced with
MOVF INDFx,W
INCF FSRx

brw becomes
addwf PCL, F ; as long as you don't overflow pcl

pic 18 has no rrf code
repl with rrcf

PIC 18F2620 version , not tested did compile ok

Code:

#CONFIG
  CONFIG  OSC=INTIO67, FCMEN=OFF, IESO=OFF, PWRT=OFF, BOREN=SBORDIS, BORV=3
  CONFIG  WDT=ON, WDTPS=512, CCP2MX=PORTC, PBADEN=OFF, LPT1OSC=OFF, MCLRE=ON
  CONFIG  STVREN=ON, LVP=OFF, XINST=OFF, DEBUG=OFF, CP0=OFF, CP1=OFF, CP2=OFF
  CONFIG  CP3=OFF, CPB=OFF, CPD=OFF, WRT0=OFF, WRT1=OFF, WRT2=OFF, WRT3=OFF
  CONFIG  WRTC=OFF, WRTB=OFF, WRTD=OFF, EBTR0=OFF, EBTR1=OFF, EBTR2=OFF
  CONFIG  EBTR3=OFF, EBTRB=OFF
#ENDCONFIG
 

define      OSC 32    ' (8 x 4 = 32)
; --- *** Oscillator  *** ---------------------------------------------------
OSCCON = %01110000      'Int Osc: 8MHz 
                        '(Bits 4, 5 & 6 determine the internal clock speed). 
                        ' 111 = 8MHz   110 = 4MHz
'OSCTUNE = %11000000   'PLL is disabled.   what??????????????
OSCTUNE.6 = 1   'PLL is enabled.
TRISA = 0
TRISB = 0
TRISC = 0
 
'CMCON = 7          'Disable the comparators of PortA
'ADCON0 = 0         'Disable ADC
ADCON1 = 15        'All pins of Port A are digital I/O
'    ANSELb = 0
'    ANSELA = 0
'    ANSELC = 0
    LED    VAR  PORTB.0  ' Assign name "LED" to 
         
    USERCOMMAND "DISPLED"    ; BUFFER{,COLON }
    USERCOMMAND "STRLEN"     ; BUFFER
    USERCOMMAND "RJUSTBUFF"  ; BUFFER
    
    TM_BIT        VAR BYTE BANK0
    TM_DAT        VAR BYTE BANK0
    TM_NAK        VAR BYTE BANK0       ;set to $80 if tx error occured
    TM_DIG        VAR BYTE BANK0
    TM_BRIGHT     VAR BYTE BANK0       ;display pwm level 0 to 7
    TM_COLON      VAR BYTE BANK0       ;display colon  0/1
    TM_TMP        VAR BYTE[2] BANK0
    str_len       VAR BYTE BANK0
    
    CMD_AUTO_ADDR CON $40 
    START_ADDR    CON $c0 
    NUM_DIGITS    CON 4                ;number of 7seg leds
    COLON_FLAG    CON $80 
    DISPLAY_ON    CON $88
    ;tm1637      DIO AND CLK NEED TO BE ON SAME PORT
    @TM_OUT_PORT = LATB       ;TM_DIO  OUT
    @TM_IN_PORT  = PORTB      ;TM_DIO  IN
    @TM_CLK      = 6          ;PIN
    @TM_DIO      = 7          ;PIN
    @TM_TRIS     = TRISB 
    
    BLINK         VAR BYTE
    LEDBUFF       VAR BYTE[NUM_DIGITS +1] 
    COUNTER       VAR byte
    
GOTO OVERASM
  
ASM  
DISPLED?B  macro BUFFER       
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    L?CALL _TM_DISP4 
    endm  
DISPLED?BC  macro BUFFER ,COLON      
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    MOVE?CB COLON ,_TM_COLON 
    L?CALL _TM_DISP4 
    endm    
DISPLED?BB  macro BUFFER ,COLON      
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    MOVE?BB COLON ,_TM_COLON 
    L?CALL _TM_DISP4 
    endm 
STRLEN?B  macro BUF      
    MOVE?CB high BUF, FSR0H ;load highbyte 
    MOVE?CB low  BUF, FSR0L ;load low byte
    L?CALL   STRlen
    endm
RJUSTBUFF?B  macro BUF      
    MOVE?CB high BUF, FSR0H ;load highbyte 
    MOVE?CB low  BUF, FSR0L ;load low byte
    MOVE?CB low  BUF, _TM_TMP  ;load low byte
    MOVE?CB HIGH  BUF, _TM_TMP+1  ;load low byte
    L?CALL  STRlen
    L?CALL  _strpad
    endm  
    
           
STRlen                     ;get buffer usage size 
    CLRF     _str_len    
str_tok_chr 
    ;MOVIW    FSR0 ++       ; Get character
    MOVF INDF0,W
    INCF FSR0
    btfsC    STATUS,Z     
    goto     exit_str_null ; EXIT ON Null char
    INCF     _str_len,F    ; not null so increment index
    goto     str_tok_chr
exit_str_null
    return 
_strpad           ;right justify by padding with spaces " "
    BANKSEL _str_len 
    movlw   _NUM_DIGITS+1     ;buffer size   
    subwf   _str_len,f        ;tx string size
    comf    _str_len,f        ;the difference is number of spaces to SHIFT in
    btfsc   STATUS, Z
    goto    expd              ;if zero difference then exit
nxpd
    movf    _TM_TMP,w         ;addr of buffer l
    MOVWF   FSR0
    movf    _TM_TMP+1,w       ;addr of buffer h
    MOVWF   FSR0+1
 movlw   _NUM_DIGITS         
    addwf   FSR0,f
    movf    FSR0,w
    movwf   FSR1
    movf    FSR0+1,w
    movwf   FSR1+1
    DECF    FSR0,F             ;offset pointer 0
    BANKSEL _TM_BIT
    movlw   _NUM_DIGITS        
    movwf   _TM_BIT
nxby                          ;buffer shift right x 1
    ;MOVIW   FSR0 --
    MOVF INDF0,W
    DECF FSR0
    ;MOVWI   FSR1 --
    MOVF INDF1,W
    DECF FSR1
    DECFSZ  _TM_BIT,F
    GOTO    nxby
    movlw   0x20
    ;MOVWI   FSR1 --            ;poke a space in buff[0]  
    MOVF INDF1,W
    DECF FSR1
    BANKSEL _str_len 
    DECFSZ  _str_len,F         ;need another one ?
    goto    nxpd
expd                           ;nah!
    return
  
SEG_val
    CHK?RP  _TM_TMP
    MOVWF   _TM_TMP
    SUBLW   0x21
    btfsc   STATUS, C
    retlw   0   ;" "
    MOVF    _TM_TMP,W
    SUBLW   0x2f
    btfsc   STATUS, C
    retlw   64   ;"-"
    MOVF    _TM_TMP,W
    MOVLW   0X40
    SUBWF   _TM_TMP,W
    btfsC   STATUS, C
    GOTO    TM_ALPHA
    MOVF    _TM_TMP,W
    ANDLW   0X0F
    GOTO    TM_LU
TM_ALPHA 
    ANDLW   0xdf    ;ucase
    SUBLW   6
    btfsS   STATUS, C
    retlw   0       ;ERROR
    MOVLW   0X37
    SUBWF   _TM_TMP,W
    ANDLW   0xdf    ;ucase
TM_LU     
    addwf   PCL, F                                          
    retlw  0X3F    ;0   
    retlw  6             
    retlw  0X5B   
    retlw  0X4F 
    retlw  0X66
    retlw  0X6D                        
    retlw  0X7D  
    retlw  7   
    retlw  0X7F          
    retlw  0X67    ;9
    retlw  0X77    ;A
    retlw  0X7C    ;b
    retlw  0X39    ;C
    retlw  0X5E    ;d
    retlw  0X79    ;E
    retlw  0X71    ;F
    
TM_START    
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK
    BSF    TM_OUT_PORT,TM_DIO
    NOP
    BCF    TM_OUT_PORT,TM_DIO
    NOP
    BCF    TM_OUT_PORT,TM_CLK
    NOP
    RETURN
    
TM_STOP 
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    BCF    TM_OUT_PORT,TM_DIO 
    NOP
    BSF    TM_OUT_PORT,TM_CLK 
    NOP
    BSF    TM_OUT_PORT,TM_DIO 
    NOP
    RETURN
    
TM_WRITE 
    MOVLW  8 
    CHK?RP _TM_BIT
    MOVWF  _TM_BIT
NXBT   
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP _TM_DAT
    BTFSS  _TM_DAT,0
    GOTO   TM_0
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_DIO 
    GOTO   TM_NB
TM_0    
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_DIO  
TM_NB   
    CHK?RP _TM_DAT
    RRCF    _TM_DAT,F
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK 
    CHK?RP _TM_BIT
    DECFSZ _TM_BIT,F
    GOTO   NXBT
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP TM_TRIS
    BSF    TM_TRIS,TM_DIO 
    CHK?RP TM_IN_PORT
    BTFSC  TM_IN_PORT,TM_DIO 
    BSF    _TM_NAK,7
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK 
    NOP
    NOP
    NOP
    NOP
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP TM_TRIS 
    BCF    TM_TRIS ,TM_DIO 
    RST?RP
    RETURN
_TM_INIT
    CHK?RP  _TM_COLON
    CLRF    _TM_COLON
    CLRF    _TM_BRIGHT
    CHK?RP TM_TRIS
    BCF    TM_TRIS ,TM_DIO
    BCF    TM_TRIS ,TM_CLK
    RST?RP
    RETURN
    
_TM_DISP4 
    MOVLW   _CMD_AUTO_ADDR
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CLRF    _TM_NAK
    CALL    TM_START
    CALL    TM_WRITE
    CALL    TM_STOP
    MOVLW   _NUM_DIGITS          
    CHK?RP  _TM_DIG
    MOVWF   _TM_DIG
    MOVLW   _START_ADDR
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CALL    TM_START
    CALL    TM_WRITE 
NXDIG
    ;MOVIW   FSR0 ++
    MOVF INDF0,W
    INCF FSR0
    CALL    SEG_val
    CHK?RP  _TM_DAT
    IORWF   _TM_COLON ,W
    movwf   _TM_DAT
    CALL    TM_WRITE
    CHK?RP  _TM_DIG
    DECFSZ  _TM_DIG,F
    GOTO    NXDIG
    CALL    TM_STOP
    CHK?RP  _TM_BRIGHT 
    MOVF    _TM_BRIGHT ,W
    ANDLW   7
    IORLW   _DISPLAY_ON
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CALL    TM_START
    CALL    TM_WRITE
    CALL    TM_STOP
    RST?RP
    RETURN
ENDASM  
OVERASM: 
 
    CALL TM_INIT
    
    
 ALOOP:   
    TOGGLE LED  
    TM_BRIGHT=TM_BRIGHT-1
    if TM_BRIGHT>7 then TM_BRIGHT=7
    ARRAYWRITE LEDBUFF ,["b- ",#TM_BRIGHT,0]
    DISPLED  LEDBUFF,0
    PAUSE 500
    FOR COUNTER=0 TO 255
        ARRAYWRITE LEDBUFF ,[hex COUNTER,0]
        RJUSTBUFF  LEDBUFF 
        DISPLED  LEDBUFF,BLINK
        PAUSE 50
    NEXT
    FOR COUNTER=0 TO 255
        IF  !(COUNTER//20) THEN BLINK = TM_COLON ^ $80
        ARRAYWRITE LEDBUFF ,[sdec COUNTER,0]
        RJUSTBUFF  LEDBUFF 
        DISPLED  LEDBUFF,BLINK
        PAUSE 50
    NEXT
    goto ALOOP

**Balachandar** · - 17th October 2018, 07:23

I used your 18F2620 version of the code for TM1637. It compiles OK, but in the subsequent test with the 18F2620 on a breadboard, the LED lights up and stays lit without anything happening to the LED module. In order to make sure that the PIC is working, I added a For-Next loop to make the LED blink 3 times for 500mS each as a diagnostic routine before the main code executes. Now, the LED blinks correctly telling me that the PIC is working properly at 32MHz. But this is what happens: 3 Blinks, gap of 1 second, 3 blinks and so on. I feel, the PIC is getting reset repeatedly.

Then I tried your original code with 12F1840. The compilation goes through without any errors. But when tested with the LED module, the LED stays lit and the TM1637 LED module does not light up.

Please let me know if you want me to post the code I used for the two PICs.

**richard** · - 17th October 2018, 08:20

Then I tried your original code with 12F1840. The compilation goes through without any errors. But when tested with the LED module, the LED stays lit and the TM1637 LED module does not light up.

Please let me know if you want me to post the code I used for the two PICs.

this works for me ,its for a 12f1822 and should run on a 12f1840 as is

if you post your code I will look at it,

Code:

'****************************************************************
'*  Name    :tm1637-demo.PBP                                     *
'*  Author  : richard                                            *
'*  Notice  :                                                    *
'*          :                                                    *
'*  Date    :                                                    *
'*  Version :                                                    *
'*  Notes   : PIC12f1822                                        *
'*          :    dio on RA1  clk RA2                            *
'****************************************************************

   #CONFIG
  __config  _CONFIG1, _FOSC_INTOSC & _WDTE_ON & _PWRTE_OFF & _MCLRE_ON & _CP_OFF & _CPD_OFF & _BOREN_ON & _CLKOUTEN_OFF & _IESO_ON & _FCMEN_ON
  __config  _CONFIG2, _WRT_OFF & _PLLEN_OFF & _STVREN_ON & _BORV_19 & _LVP_OFF
#ENDCONFIG
   
 OSCCON = %01111000 '16MHz HF, software PLL disabled
 DEFINE OSC 16 
  ANSELA=0   
 
    
    USERCOMMAND "DISPLED"    ; BUFFER{,COLON }   TAKES 150uS FOR 4 DIGITS
    USERCOMMAND "STRLEN"     ; BUFFER
    USERCOMMAND "RJUSTBUFF"  ; BUFFER
    ;ALL NEED TO BE IN SAME BANK
    TM_BIT        VAR BYTE BANK0
    TM_DAT        VAR BYTE BANK0
    TM_NAK        VAR BYTE BANK0       ;set to $80 if tx error occured
    TM_DIG        VAR BYTE BANK0
    TM_BRIGHT     VAR BYTE BANK0       ;display pwm level 0 to 7
    TM_COLON      VAR BYTE BANK0       ;display colon  0/1
    TM_TMP        VAR BYTE[2] BANK0
    str_len       VAR BYTE BANK0
    ;tm1637 CONSTANTS
    CMD_AUTO_ADDR CON $40 
    START_ADDR    CON $c0 
    NUM_DIGITS    CON 4                ;number of 7seg leds
    COLON_FLAG    CON $80 
    DISPLAY_ON    CON $88
    ;tm1637      DIO AND CLK NEED TO BE ON SAME PORT
    @TM_OUT_PORT = LATA       ;TM_DIO  OUT
    @TM_IN_PORT  = PORTA      ;TM_DIO  IN
    @TM_CLK      = 2          ;PIN
    @TM_DIO      = 1         ;PIN
    @TM_TRIS     = TRISA 
    
    BLINK         VAR BYTE
    LEDBUFF       VAR BYTE[NUM_DIGITS +1] 
    COUNTER       VAR byte
    
GOTO OVERASM
  
ASM  
DISPLED?B  macro BUFFER       
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    L?CALL _TM_DISP4 
    endm  
DISPLED?BC  macro BUFFER ,COLON      
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    CHK?RP  _TM_COLON 
    MOVE?CB COLON ,_TM_COLON 
    L?CALL _TM_DISP4 
    endm    
DISPLED?BB  macro BUFFER ,COLON      
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    CHK?RP  _TM_COLON 
    MOVE?BB COLON ,_TM_COLON 
    L?CALL _TM_DISP4 
    endm 
STRLEN?B  macro BUF      
    MOVE?CB high BUF, FSR0H ;load highbyte 
    MOVE?CB low  BUF, FSR0L ;load low byte
    L?CALL   STRlen
    endm
RJUSTBUFF?B  macro BUF      
    MOVE?CB high BUF, FSR0H ;load highbyte 
    MOVE?CB low  BUF, FSR0L ;load low byte
    CHK?RP   _TM_TMP 
    MOVE?CB low  BUF, _TM_TMP  ;load low byte
    MOVE?CB HIGH  BUF, _TM_TMP+1  ;load low byte
    L?CALL  STRlen
    L?CALL  _strpad
    endm  
    
           
STRlen                     ;get buffer usage size 
    CHK?RP   _str_len 
    CLRF     _str_len    
str_tok_chr 
    MOVIW    FSR0 ++       ; Get character
    btfsC    STATUS,Z     
    goto     exit_str_null ; EXIT ON Null char
    INCF     _str_len,F    ; not null so increment index
    goto     str_tok_chr
exit_str_null
    BANKSEL 0
    return 
_strpad           ;right justify by padding with spaces " "
    CHK?RP  _str_len 
    movlw   _NUM_DIGITS+1     ;buffer size 
    subwf   _str_len,f        ;tx string size  
    btfsc   STATUS, C         ;tx string size  gotcha
    goto    expd              ;if positive difference then exit buffer overrun will occur  ;tx string size  gotcha
    comf    _str_len,f        ;the difference is number of spaces to SHIFT in
    btfsc   STATUS, Z
    goto    expd              ;if zero difference then exit
    movlw   _NUM_DIGITS       ;buffer size 
    addwf   _TM_TMP,f         ;add  NUM_DIGITS to  addr of buffer
nxpd
    movf    _TM_TMP,w         ;low (addr of buffer + NUM_DIGITS )
    MOVWF   FSR0L
    movwf   FSR1L
    movf    _TM_TMP+1,w       ;high (addr of buffer + NUM_DIGITS )
    MOVWF   FSR0H
    movwf   FSR1H 
    DECF    FSR0L,F            ;offset pointer 0
    movlw   _NUM_DIGITS 
    movwf   _TM_BIT
nxby                          ;buffer shift right x 1
    MOVIW   FSR0 --
    MOVWI   FSR1 --
    DECFSZ  _TM_BIT,F
    GOTO    nxby
    movlw   0x20
    MOVWI   FSR1 --            ;poke a space in buff[0]
    DECFSZ  _str_len,F         ;need another one ?
    goto    nxpd
expd                           ;nah!
    BANKSEL 0
    return
  
SEG_val         ;VALID INPUT  0-9 ,A-F, a-f ," " ,-
    CHK?RP  _TM_TMP
    MOVWF   _TM_TMP
    SUBLW   0x21
    btfsc   STATUS, C
    retlw   0   ;" "
    MOVF    _TM_TMP,W
    SUBLW   0x2f
    btfsc   STATUS, C
    retlw   64   ;"-"
    MOVF    _TM_TMP,W
    MOVLW   0X40
    SUBWF   _TM_TMP,W
    btfsC   STATUS, C
    GOTO    TM_ALPHA
    MOVF    _TM_TMP,W
    ANDLW   0X0F
    GOTO    TM_LU
TM_ALPHA 
    ANDLW   0xdf    ;ucase
    SUBLW   6
    btfsS   STATUS, C
    retlw   0       ;ERROR
    MOVLW   0X37
    SUBWF   _TM_TMP,W
    ANDLW   0xdf    ;ucase
TM_LU     
    BRW                                         
    retlw  0X3F    ;0   
    retlw  6             
    retlw  0X5B   
    retlw  0X4F 
    retlw  0X66
    retlw  0X6D                        
    retlw  0X7D  
    retlw  7   
    retlw  0X7F          
    retlw  0X67    ;9
    retlw  0X77    ;A
    retlw  0X7C    ;b
    retlw  0X39    ;C
    retlw  0X5E    ;d
    retlw  0X79    ;E
    retlw  0X71    ;F
    
TM_START    
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK
    BSF    TM_OUT_PORT,TM_DIO
    NOP
    BCF    TM_OUT_PORT,TM_DIO
    NOP
    BCF    TM_OUT_PORT,TM_CLK
    ;NOP
    RETURN
    
TM_STOP 
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    BCF    TM_OUT_PORT,TM_DIO 
    NOP
    BSF    TM_OUT_PORT,TM_CLK 
    NOP
    BSF    TM_OUT_PORT,TM_DIO 
    ;NOP
    RETURN
    
TM_WRITE 
    MOVLW  8 
    CHK?RP _TM_BIT
    MOVWF  _TM_BIT
NXBT   
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP _TM_DAT
    BTFSS  _TM_DAT,0
    GOTO   TM_0
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_DIO 
    GOTO   TM_NB
TM_0    
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_DIO  
TM_NB   
    CHK?RP _TM_DAT
    RRF    _TM_DAT,F
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK 
    CHK?RP _TM_BIT
    DECFSZ _TM_BIT,F
    GOTO   NXBT
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP TM_TRIS
    BSF    TM_TRIS,TM_DIO 
    CHK?RP TM_IN_PORT
    BTFSC  TM_IN_PORT,TM_DIO 
    BSF    _TM_NAK,7
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK 
    NOP
    NOP
    NOP
    NOP
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP TM_TRIS 
    BCF    TM_TRIS ,TM_DIO 
    BANKSEL 0
    RETURN
_TM_INIT
    CHK?RP  _TM_COLON
    CLRF    _TM_COLON
    CLRF    _TM_BRIGHT
    CHK?RP TM_TRIS
    BCF    TM_TRIS ,TM_DIO
    BCF    TM_TRIS ,TM_CLK
    BANKSEL 0
    RETURN
    
_TM_DISP4
    CHK?RP  _TM_DAT
    MOVLW   _CMD_AUTO_ADDR
    MOVWF   _TM_DAT
    CLRF    _TM_NAK
    CALL    TM_START
    CALL    TM_WRITE
    CALL    TM_STOP
    MOVLW   _NUM_DIGITS          
    CHK?RP  _TM_DIG
    MOVWF   _TM_DIG
    MOVLW   _START_ADDR
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CALL    TM_START
    CALL    TM_WRITE 
NXDIG
    MOVIW   FSR0 ++
    CALL    SEG_val
    CHK?RP  _TM_DAT
    IORWF   _TM_COLON ,W
    movwf   _TM_DAT
    CALL    TM_WRITE
    CHK?RP  _TM_DIG
    DECFSZ  _TM_DIG,F
    GOTO    NXDIG
    CALL    TM_STOP
    CHK?RP  _TM_BRIGHT 
    MOVF    _TM_BRIGHT ,W
    ANDLW   7
    IORLW   _DISPLAY_ON
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CALL    TM_START
    CALL    TM_WRITE
    CALL    TM_STOP
    BANKSEL 0
    RETURN
ENDASM  
OVERASM: 
 
    CALL TM_INIT
    
 ALOOP:   
     
    TM_BRIGHT=TM_BRIGHT-1
    if TM_BRIGHT>7 then TM_BRIGHT=7
    ARRAYWRITE LEDBUFF ,["b- ",#TM_BRIGHT,0]
    DISPLED  LEDBUFF,0
    PAUSE 500
    FOR COUNTER=0 TO 255
        ARRAYWRITE LEDBUFF ,[dec COUNTER,0]
        RJUSTBUFF  LEDBUFF 
        DISPLED  LEDBUFF,0
        PAUSE 50
    NEXT
    FOR COUNTER=0 TO 255
        IF  !(COUNTER//20) THEN BLINK = TM_COLON ^ COLON_FLAG 
        ARRAYWRITE LEDBUFF ,[sdec COUNTER,0]
        RJUSTBUFF  LEDBUFF 
        DISPLED  LEDBUFF,BLINK
        PAUSE 50
    NEXT
    GOTO ALOOP

**Balachandar** · - 17th October 2018, 12:29

Compiled your code for 12F1822 for 12F1840 after adding the 'Blink LED 3 times' routine. Compilation went through without a hitch followed by programming a 12F1840. When tested, the LED blinks 3 times and goes off. Nothing else happens.

Compiled once again, this time changing the uC to 12F1822 in MC Studio. Again, the compilation went through fine. But on testing, the LED blinks and goes off, but the LED module does not come to life.

There is one more strange thing I am encountering. A month back, I bought 5 pieces of 12F1840-I/SN (SOIC package) from Ali Exp for $ 3.22. The laser printing/etching on the chip clearly shows "12F1840" and it works at 5V without any problem. But PICKIT2 identifies it as 12LF1840 and the voltage will not go beyond 3.6V. Of course, even if I use an LF version of the PIC, the TM1637 LED module should work. Every now and then, I connect the module to a Nano and check in order to make sure that there is nothing wrong with the module. Whether the voltage is 5 or 3.3, the module works fine. Understandably, the brightness is less at 3.3V.

Code used with 12F1840:

Code:

' 12F1840 Pinout:
'  -------------------------------------------------------  
'  	VDD                         VSS 
'  	PortA.5 = Not_used          PortA.0 = LED            
'  	PortA.4 = Not_used          PortA.1 = DIO
'  	PortA.3 = Not_used          PortA.2 = CLK
'  -------------------------------------------------------                                                       

#CONFIG
    __config _CONFIG1, _FOSC_INTOSC & _MCLRE_ON & _CP_OFF & _CPD_OFF
    __config _CONFIG2, _PLLEN_OFF & _LVP_OFF
#ENDCONFIG

OSCCON = %01111000 '16MHz HF, software PLL disabled
DEFINE OSC 16 

'Port direction
TRISA = %001000         'A.3 is input, rest are outputs.
 
ANSELA = 0				'Disable A to D
CM1CON0 = 0             'Disable comparator
 
    
    USERCOMMAND "DISPLED"    ; BUFFER{,COLON }   TAKES 150uS FOR 4 DIGITS
    USERCOMMAND "STRLEN"     ; BUFFER
    USERCOMMAND "RJUSTBUFF"  ; BUFFER
    ;ALL NEED TO BE IN SAME BANK
    TM_BIT        VAR BYTE BANK0
    TM_DAT        VAR BYTE BANK0
    TM_NAK        VAR BYTE BANK0       ;set to $80 if tx error occured
    TM_DIG        VAR BYTE BANK0
    TM_BRIGHT     VAR BYTE BANK0       ;display pwm level 0 to 7
    TM_COLON      VAR BYTE BANK0       ;display colon  0/1
    TM_TMP        VAR BYTE[2] BANK0
    str_len       VAR BYTE BANK0
    
    ;tm1637 CONSTANTS
    CMD_AUTO_ADDR CON $40 
    START_ADDR    CON $c0 
    NUM_DIGITS    CON 4                ;number of 7seg leds
    COLON_FLAG    CON $80 
    DISPLAY_ON    CON $88
    ;tm1637      DIO AND CLK NEED TO BE ON SAME PORT
    @TM_OUT_PORT = LATA       ;TM_DIO  OUT
    @TM_IN_PORT  = PORTA      ;TM_DIO  IN
    @TM_CLK      = 2          ;PIN
    @TM_DIO      = 1          ;PIN
    @TM_TRIS     = TRISA 
    
    BLINK         VAR BYTE
    LEDBUFF       VAR BYTE[NUM_DIGITS +1] 
    COUNTER       VAR byte
    Cnt           var byte             ;for use in loops

LED var LATA.0

'Diagnostic routine
DiagRoutine:                           
for cnt = 1 to 3           'Blink LED 3 times.
led = 1 : pause 500 
led = 0 : pause 500
next cnt

    
GOTO OVERASM
  
ASM  
DISPLED?B  macro BUFFER       
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    L?CALL _TM_DISP4 
    endm  
DISPLED?BC  macro BUFFER ,COLON      
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    CHK?RP  _TM_COLON 
    MOVE?CB COLON ,_TM_COLON 
    L?CALL _TM_DISP4 
    endm    
DISPLED?BB  macro BUFFER ,COLON      
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    CHK?RP  _TM_COLON 
    MOVE?BB COLON ,_TM_COLON 
    L?CALL _TM_DISP4 
    endm 
STRLEN?B  macro BUF      
    MOVE?CB high BUF, FSR0H ;load highbyte 
    MOVE?CB low  BUF, FSR0L ;load low byte
    L?CALL   STRlen
    endm
RJUSTBUFF?B  macro BUF      
    MOVE?CB high BUF, FSR0H ;load highbyte 
    MOVE?CB low  BUF, FSR0L ;load low byte
    CHK?RP   _TM_TMP 
    MOVE?CB low  BUF, _TM_TMP  ;load low byte
    MOVE?CB HIGH  BUF, _TM_TMP+1  ;load low byte
    L?CALL  STRlen
    L?CALL  _strpad
    endm  
    
           
STRlen                     ;get buffer usage size 
    CHK?RP   _str_len 
    CLRF     _str_len    
str_tok_chr 
    MOVIW    FSR0 ++       ; Get character
    btfsC    STATUS,Z     
    goto     exit_str_null ; EXIT ON Null char
    INCF     _str_len,F    ; not null so increment index
    goto     str_tok_chr
exit_str_null
    BANKSEL 0
    return 
_strpad           ;right justify by padding with spaces " "
    CHK?RP  _str_len 
    movlw   _NUM_DIGITS+1     ;buffer size 
    subwf   _str_len,f        ;tx string size  
    btfsc   STATUS, C         ;tx string size  gotcha
    goto    expd              ;if positive difference then exit buffer overrun will occur  ;tx string size  gotcha
    comf    _str_len,f        ;the difference is number of spaces to SHIFT in
    btfsc   STATUS, Z
    goto    expd              ;if zero difference then exit
    movlw   _NUM_DIGITS       ;buffer size 
    addwf   _TM_TMP,f         ;add  NUM_DIGITS to  addr of buffer
nxpd
    movf    _TM_TMP,w         ;low (addr of buffer + NUM_DIGITS )
    MOVWF   FSR0L
    movwf   FSR1L
    movf    _TM_TMP+1,w       ;high (addr of buffer + NUM_DIGITS )
    MOVWF   FSR0H
    movwf   FSR1H 
    DECF    FSR0L,F            ;offset pointer 0
    movlw   _NUM_DIGITS 
    movwf   _TM_BIT
nxby                          ;buffer shift right x 1
    MOVIW   FSR0 --
    MOVWI   FSR1 --
    DECFSZ  _TM_BIT,F
    GOTO    nxby
    movlw   0x20
    MOVWI   FSR1 --            ;poke a space in buff[0]
    DECFSZ  _str_len,F         ;need another one ?
    goto    nxpd
expd                           ;nah!
    BANKSEL 0
    return
  
SEG_val         ;VALID INPUT  0-9 ,A-F, a-f ," " ,-
    CHK?RP  _TM_TMP
    MOVWF   _TM_TMP
    SUBLW   0x21
    btfsc   STATUS, C
    retlw   0   ;" "
    MOVF    _TM_TMP,W
    SUBLW   0x2f
    btfsc   STATUS, C
    retlw   64   ;"-"
    MOVF    _TM_TMP,W
    MOVLW   0X40
    SUBWF   _TM_TMP,W
    btfsC   STATUS, C
    GOTO    TM_ALPHA
    MOVF    _TM_TMP,W
    ANDLW   0X0F
    GOTO    TM_LU
TM_ALPHA 
    ANDLW   0xdf    ;ucase
    SUBLW   6
    btfsS   STATUS, C
    retlw   0       ;ERROR
    MOVLW   0X37
    SUBWF   _TM_TMP,W
    ANDLW   0xdf    ;ucase
TM_LU     
    BRW                                         
    retlw  0X3F    ;0   
    retlw  6             
    retlw  0X5B   
    retlw  0X4F 
    retlw  0X66
    retlw  0X6D                        
    retlw  0X7D  
    retlw  7   
    retlw  0X7F          
    retlw  0X67    ;9
    retlw  0X77    ;A
    retlw  0X7C    ;b
    retlw  0X39    ;C
    retlw  0X5E    ;d
    retlw  0X79    ;E
    retlw  0X71    ;F
    
TM_START    
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK
    BSF    TM_OUT_PORT,TM_DIO
    NOP
    BCF    TM_OUT_PORT,TM_DIO
    NOP
    BCF    TM_OUT_PORT,TM_CLK
    ;NOP
    RETURN
    
TM_STOP 
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    BCF    TM_OUT_PORT,TM_DIO 
    NOP
    BSF    TM_OUT_PORT,TM_CLK 
    NOP
    BSF    TM_OUT_PORT,TM_DIO 
    ;NOP
    RETURN
    
TM_WRITE 
    MOVLW  8 
    CHK?RP _TM_BIT
    MOVWF  _TM_BIT
NXBT   
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP _TM_DAT
    BTFSS  _TM_DAT,0
    GOTO   TM_0
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_DIO 
    GOTO   TM_NB
TM_0    
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_DIO  
TM_NB   
    CHK?RP _TM_DAT
    RRF    _TM_DAT,F
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK 
    CHK?RP _TM_BIT
    DECFSZ _TM_BIT,F
    GOTO   NXBT
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP TM_TRIS
    BSF    TM_TRIS,TM_DIO 
    CHK?RP TM_IN_PORT
    BTFSC  TM_IN_PORT,TM_DIO 
    BSF    _TM_NAK,7
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK 
    NOP
    NOP
    NOP
    NOP
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP TM_TRIS 
    BCF    TM_TRIS ,TM_DIO 
    BANKSEL 0
    RETURN
_TM_INIT
    CHK?RP  _TM_COLON
    CLRF    _TM_COLON
    CLRF    _TM_BRIGHT
    CHK?RP TM_TRIS
    BCF    TM_TRIS ,TM_DIO
    BCF    TM_TRIS ,TM_CLK
    BANKSEL 0
    RETURN
    
_TM_DISP4
    CHK?RP  _TM_DAT
    MOVLW   _CMD_AUTO_ADDR
    MOVWF   _TM_DAT
    CLRF    _TM_NAK
    CALL    TM_START
    CALL    TM_WRITE
    CALL    TM_STOP
    MOVLW   _NUM_DIGITS          
    CHK?RP  _TM_DIG
    MOVWF   _TM_DIG
    MOVLW   _START_ADDR
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CALL    TM_START
    CALL    TM_WRITE 
NXDIG
    MOVIW   FSR0 ++
    CALL    SEG_val
    CHK?RP  _TM_DAT
    IORWF   _TM_COLON ,W
    movwf   _TM_DAT
    CALL    TM_WRITE
    CHK?RP  _TM_DIG
    DECFSZ  _TM_DIG,F
    GOTO    NXDIG
    CALL    TM_STOP
    CHK?RP  _TM_BRIGHT 
    MOVF    _TM_BRIGHT ,W
    ANDLW   7
    IORLW   _DISPLAY_ON
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CALL    TM_START
    CALL    TM_WRITE
    CALL    TM_STOP
    BANKSEL 0
    RETURN
ENDASM  
OVERASM: 
 
    CALL TM_INIT
    
 ALOOP:   
     
    TM_BRIGHT=TM_BRIGHT-1
    if TM_BRIGHT>7 then TM_BRIGHT=7
    ARRAYWRITE LEDBUFF ,["b- ",#TM_BRIGHT,0]
    DISPLED  LEDBUFF,0
    PAUSE 500
    FOR COUNTER=0 TO 255
        ARRAYWRITE LEDBUFF ,[dec COUNTER,0]
        RJUSTBUFF  LEDBUFF 
        DISPLED  LEDBUFF,0
        PAUSE 50
    NEXT
    FOR COUNTER=0 TO 255
        IF  !(COUNTER//20) THEN BLINK = TM_COLON ^ COLON_FLAG 
        ARRAYWRITE LEDBUFF ,[sdec COUNTER,0]
        RJUSTBUFF  LEDBUFF 
        DISPLED  LEDBUFF,BLINK
        PAUSE 50
    NEXT
    GOTO ALOOP

**richard** · - 17th October 2018, 13:37

Compiled your code for 12F1822 for 12F1840 after adding the 'Blink LED 3 times' routine. Compilation went through without a hitch followed by programming a 12F1840. When tested, the LED blinks 3 times and goes off. Nothing else happens

.

WORKS just fine for me, even at 3v

pic18 version [can't believe how many changes it needed]

Code:

'****************************************************************
'*  Name    :tm1637-demo.PBP                                     *
'*  Author  : richard                                            *
'*  Notice  :                                                    *
'*          :                                                    *
'*  Date    :                                                    *
'*  Version :                                                    *
'*  Notes   : PIC18F45K20                                     *
'*          :    dio on RB0  clk RB1                           *
'****************************************************************
 
#CONFIG
  CONFIG  FOSC = INTIO67
  CONFIG  FCMEN = OFF
  CONFIG  IESO = OFF
  CONFIG  PWRT = OFF
  CONFIG  BOREN = SBORDIS
  CONFIG  BORV = 18
  CONFIG  WDTEN = ON
  CONFIG  WDTPS = 512
  CONFIG  CCP2MX = PORTC
  CONFIG  PBADEN = OFF
  CONFIG  LPT1OSC = OFF
  CONFIG  HFOFST = ON
  CONFIG  MCLRE = ON
  CONFIG  STVREN = ON
  CONFIG  LVP = OFF
  CONFIG  XINST = OFF
  CONFIG  DEBUG = OFF
  CONFIG  CP0 = OFF
  CONFIG  CP1 = OFF
  CONFIG  CP2 = OFF
  CONFIG  CP3 = OFF
  CONFIG  CPB = OFF
  CONFIG  CPD = OFF
  CONFIG  WRT0 = OFF
  CONFIG  WRT1 = OFF
  CONFIG  WRT2 = OFF
  CONFIG  WRT3 = OFF
  CONFIG  WRTC = OFF
  CONFIG  WRTB = OFF
  CONFIG  WRTD = OFF
  CONFIG  EBTR0 = OFF
  CONFIG  EBTR1 = OFF
  CONFIG  EBTR2 = OFF
  CONFIG  EBTR3 = OFF
  CONFIG  EBTRB = OFF
#ENDCONFIG
DEFINE OSC 32
   
   osccon=$60   '32 mhz
    OSCTUNE.6=1
   
    trisb.4=0
   ANSELH=0
    LED    VAR  PORTB.4  ' Assign name "LED" to 
         
    USERCOMMAND "DISPLED"    ; BUFFER{,COLON }
    USERCOMMAND "STRLEN"     ; BUFFER
    USERCOMMAND "RJUSTBUFF"  ; BUFFER
    
    TM_BIT        VAR BYTE BANK0
    TM_DAT        VAR BYTE BANK0
    TM_NAK        VAR BYTE BANK0       ;set to $80 if tx error occured
    TM_DIG        VAR BYTE BANK0
    TM_BRIGHT     VAR BYTE BANK0       ;display pwm level 0 to 7
    TM_COLON      VAR BYTE BANK0       ;display colon  0/1
    TM_TMP        VAR BYTE[2] BANK0
    str_len       VAR BYTE BANK0
    
    CMD_AUTO_ADDR CON $40 
    START_ADDR    CON $c0 
    NUM_DIGITS    CON 4                ;number of 7seg leds
    COLON_FLAG    CON $80 
    DISPLAY_ON    CON $88
    ;tm1637      DIO AND CLK NEED TO BE ON SAME PORT
    @TM_OUT_PORT = LATB       ;TM_DIO  OUT
    @TM_IN_PORT  = PORTB      ;TM_DIO  IN
    @TM_CLK      = 1          ;PIN
    @TM_DIO      = 0          ;PIN
    @TM_TRIS     = TRISB 
    
    BLINK         VAR BYTE
    LEDBUFF       VAR BYTE[NUM_DIGITS +1] 
    COUNTER       VAR BYTE
    
GOTO OVERASM
  
ASM  
DISPLED?B  macro BUFFER       
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    L?CALL _TM_DISP4 
    endm  
DISPLED?BC  macro BUFFER ,COLON      
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    MOVE?CB COLON ,_TM_COLON 
    L?CALL _TM_DISP4 
    endm    
DISPLED?BB  macro BUFFER ,COLON      
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    MOVE?BB COLON ,_TM_COLON 
    L?CALL _TM_DISP4 
    endm 
STRLEN?B  macro BUF      
    MOVE?CB high BUF, FSR0H ;load highbyte 
    MOVE?CB low  BUF, FSR0L ;load low byte
    L?CALL   STRlen
    endm
RJUSTBUFF?B  macro BUF      
    MOVE?CB high BUF, FSR0H ;load highbyte 
    MOVE?CB low  BUF, FSR0L ;load low byte
    MOVE?CB low  BUF, _TM_TMP  ;load low byte
    MOVE?CB HIGH  BUF, _TM_TMP+1  ;load low byte
    L?CALL  STRlen
    L?CALL  _strpad
    endm  
 
      
     
  
           
STRlen                     ;get buffer usage size 
    CLRF     _str_len    
str_tok_chr 
    ;MOVIW    FSR0 ++       ; Get character
    MOVF INDF0,W
    INFSNZ FSR0L
    incf   FSR0H
    btfsC    STATUS,Z     
    goto     exit_str_null ; EXIT ON Null char
    INCF     _str_len,F    ; not null so increment index
    goto     str_tok_chr
exit_str_null
    return 
  
 
_strpad           ;right justify by padding with spaces " "
    BANKSEL 0
    MOVLW   5
    ;ADDWF   _str_field_size,w  ;buffer size
    subwf   _str_len,f         ;tx string size 
    btfsc   STATUS, C          ;tx string size  gotcha
    goto    expd ;if positive difference then exit buffer overrun will occur  ;tx string size  gotcha
    comf    _str_len           ;the difference is number of spaces to SHIFT in
    btfsc   STATUS, Z
    goto    expd               ;if zero difference then exit
    moVLW    4  ;buffer size
    addwf   _TM_TMP,f         ;add  NUM_DIGITS to  addr of buffer
    ;btfsc   STATUS, C
    ;INCF    _STR_TMP+1,f
nxpd
    movf    _TM_TMP,w         ;low (addr of buffer + NUM_DIGITS )
    MOVWF   FSR0L
    movwf   FSR1L
    DECF    FSR0L,F             ;offset pointer 0
    ;btfsc   STATUS, C 
    ;DECF    FSR0H,F 
    movf    _TM_TMP+1,w        ;high (addr of buffer + NUM_DIGITS )
    MOVWF   FSR0H
    movwf   FSR1H
    MOVLW   4 
    movwf   _TM_BIT
nxby                            ;buffer shift right x 1
   ifdef TBLPTRL                ;fsr 
      movf  POSTDEC0, W         ;[pic18]
      MOVWF POSTDEC1
   else 
      MOVIW FSR0 --
      MOVWI FSR1 --
   endif
    DECFSZ  _TM_BIT,F
    GOTO    nxby
    movlw   0x20
    ifdef TBLPTRL               ;fsr 
      MOVWF POSTDEC1
    else 
      MOVWI FSR1 --
    endif
    DECFSZ  _str_len,F          ;need another one ?
    goto    nxpd
expd                            ;nah!
    BANKSEL 0
    return
SEG_val
    CHK?RP  _TM_TMP
    MOVWF   _TM_TMP
    CLRF _TM_TMP +1
    SUBLW   0x21
    btfsc   STATUS, C
    retlw   0   ;" "
    MOVF    _TM_TMP,W
    SUBLW   0x2f
    btfsc   STATUS, C
    retlw   64   ;"-"
    MOVF    _TM_TMP,W
    MOVLW   0X40
    SUBWF   _TM_TMP,W
    btfsC   STATUS, C
    GOTO    TM_ALPHA
    MOVF    _TM_TMP,W
    ANDLW   0X0F
    GOTO    TM_LU
TM_ALPHA 
    ANDLW   0xdf    ;ucase
    SUBLW   6
    btfsS   STATUS, C
    retlw   0       ;ERROR
    MOVLW   0X37
    SUBWF   _TM_TMP,W
    ANDLW   0xdf    ;ucase
TM_LU  
    addlw   LOW TABLE_START
    movwf   TBLPTRL
    rlcf    _TM_TMP +1 ,w
    addlw   HIGH TABLE_START 
    movwf   TBLPTRH
    movlw   UPPER TABLE_START 
    movwf   TBLPTRU
    tblrd   *+
    movf   TABLAT,w    
    return
      
  
TABLE_START 
 db    0X3F,6,0X5B,0X4F,0X66,0X6D,0X7D,7,0X7F,0X67,0X77 ,0X7C ,0X39 ,0X5E ,0X79 ,0X71                        
    
    
TM_START    
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK
    BSF    TM_OUT_PORT,TM_DIO
    NOP
    BCF    TM_OUT_PORT,TM_DIO
    NOP
    BCF    TM_OUT_PORT,TM_CLK
    NOP
    RETURN
    
TM_STOP 
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    BCF    TM_OUT_PORT,TM_DIO 
    NOP
    BSF    TM_OUT_PORT,TM_CLK 
    NOP
    BSF    TM_OUT_PORT,TM_DIO 
    NOP
    RETURN
    
TM_WRITE 
    MOVLW  8 
    CHK?RP _TM_BIT
    MOVWF  _TM_BIT
NXBT   
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP _TM_DAT
    BTFSS  _TM_DAT,0
    GOTO   TM_0
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_DIO 
    GOTO   TM_NB
TM_0    
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_DIO  
TM_NB   
    CHK?RP _TM_DAT
    RRCF    _TM_DAT,F
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK 
    CHK?RP _TM_BIT
    DECFSZ _TM_BIT,F
    GOTO   NXBT
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP TM_TRIS
    BSF    TM_TRIS,TM_DIO 
    CHK?RP TM_IN_PORT
    BTFSC  TM_IN_PORT,TM_DIO 
    BSF    _TM_NAK,7
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK 
    NOP
    NOP
    NOP
    NOP
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP TM_TRIS 
    BCF    TM_TRIS ,TM_DIO 
    RST?RP
    RETURN
_TM_INIT
    CHK?RP  _TM_COLON
    CLRF    _TM_COLON
    CLRF    _TM_BRIGHT
    CHK?RP TM_TRIS
    BCF    TM_TRIS ,TM_DIO
    BCF    TM_TRIS ,TM_CLK
    RST?RP
    RETURN
    
_TM_DISP4 
    MOVLW   _CMD_AUTO_ADDR
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CLRF    _TM_NAK
    CALL    TM_START
    CALL    TM_WRITE
    CALL    TM_STOP
    MOVLW   _NUM_DIGITS          
    CHK?RP  _TM_DIG
    MOVWF   _TM_DIG
    MOVLW   _START_ADDR
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CALL    TM_START
    CALL    TM_WRITE 
NXDIG
    ;MOVIW   FSR0 ++
    MOVF INDF0,W
    INFSNZ FSR0L
    incf   FSR0H
    CALL    SEG_val
    CHK?RP  _TM_DAT
    IORWF   _TM_COLON ,W
    movwf   _TM_DAT
    CALL    TM_WRITE
    CHK?RP  _TM_DIG
    DECFSZ  _TM_DIG,F
    GOTO    NXDIG
    CALL    TM_STOP
    CHK?RP  _TM_BRIGHT 
    MOVF    _TM_BRIGHT ,W
    ANDLW   7
    IORLW   _DISPLAY_ON
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CALL    TM_START
    CALL    TM_WRITE
    CALL    TM_STOP
    RST?RP
    RETURN
    
    
_TM_DISP1     ; WRITES TO A DISP POSN TM_TMP HOLDS DATA FOR TM_DIG IS POSN  0-3
    CHK?RP  _TM_DAT
    MOVLW   _CMD_AUTO_ADDR
    MOVWF   _TM_DAT
    CALL    TM_START
    CALL    TM_WRITE
    CALL    TM_STOP
    MOVLW   _START_ADDR
    addwf   _TM_DIG,W
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CALL    TM_START
    CALL    TM_WRITE 
    CHK?RP  _TM_TMP
    MOVF    _TM_TMP,W
    movwf   _TM_DAT
    CALL    TM_WRITE
    CALL    TM_STOP
    BANKSEL 0
    RETURN 
    
    
    
    
    
    
    
ENDASM  
OVERASM: 
    FOR COUNTER=0 TO 3
     TOGGLE LED 
       PAUSE 500
    next
    CALL TM_INIT
  BLINK=0  
    
 ALOOP:   
     TOGGLE LED  
    TM_BRIGHT=TM_BRIGHT-1
    if TM_BRIGHT>7 then TM_BRIGHT=7
    ARRAYWRITE LEDBUFF ,["B- ",#TM_BRIGHT]
   
    DISPLED  LEDBUFF,0
    
    
    PAUSE 500
    FOR COUNTER=0 TO 255
        ARRAYWRITE LEDBUFF ,[hex COUNTER,0]
        RJUSTBUFF  LEDBUFF 
        DISPLED  LEDBUFF,0
        PAUSE 50
    NEXT
    FOR COUNTER=0 TO 255
        IF  !(COUNTER//20) THEN BLINK = TM_COLON ^ $80
        ARRAYWRITE LEDBUFF ,[sdec COUNTER,0]
        RJUSTBUFF  LEDBUFF 
        DISPLED  LEDBUFF,BLINK
        PAUSE 50
    NEXT
    goto ALOOP

**Balachandar** · - 18th October 2018, 03:29

WOW! FINALLY, IT HAPPENED!!

The TM1637 LED display module came alive!!!
I used your revised code for 18F devices and after I made a few changes in the CONFIG section, the compilation for 18F2620 was successful.
I programmed and inserted the PIC in the breadboard and powered it up. After the LED blinked 3 times, it was a real pleasant sight to see the digits appear on the LED module.
Thanks a lot Richard, for your patience and helping nature.

The code I used for 18F2620 is reproduced below.
OSCCON = $60; OSCTUNE.6 = 1 - These two settings in your code make the Osc 16Mhz (4MHz x 4). So, I changed the Osc speed from 32 to 16MHz. Later, I tried the code at 8MHz and 4MHz. It works beautifully at those speeds too.

Code:

'-------------------------------------------------------------------------------
'PIC used: 18F2620
'Pinout
'                  ---------                                                        
'   E.3 =         1         28  B.7 = 
'   A.0 =         2         27  B.6 = 
'   A.1 =         3         26  B.5 = 
'   A.2 =         4         25  B.4 = LED
'   A.3 =         5         24  B.3 = 
'   A.4 =         6         23  B.2 = 
'   A.5 =         7         22  B.1 = CLK
'   Gnd           8         21  B.0 = DIO
'   A.7 =         9         20  +5V 
'   A.6 =        10         19  Gnd     
'   C.0 =        11         18  C.7 = 
'   C.1 =        12         17  C.6 = 
'   C.2 =        13         16  C.5 = 
'   C.3 =        14         15  C.4 =  
'                  ---------
'-------------------------------------------------------------------------------
#CONFIG
  CONFIG  OSC = INTIO67         ; CONFIG  FOSC = INTIO67
  CONFIG  FCMEN = OFF
  CONFIG  IESO = OFF
  CONFIG  PWRT = OFF
  CONFIG  BOREN = SBORDIS
  CONFIG  BORV = 2              ; CONFIG  BORV = 18
  CONFIG  WDT = ON              ; CONFIG  WDTEN = ON
  CONFIG  WDTPS = 512
  CONFIG  CCP2MX = PORTC
  CONFIG  PBADEN = OFF
  CONFIG  LPT1OSC = OFF
;  CONFIG  HFOFST = ON        ;Not applicable to 18F2620
  CONFIG  MCLRE = ON
  CONFIG  STVREN = ON
  CONFIG  LVP = OFF
  CONFIG  XINST = OFF
  CONFIG  DEBUG = OFF
  CONFIG  CP0 = OFF
  CONFIG  CP1 = OFF
  CONFIG  CP2 = OFF
  CONFIG  CP3 = OFF
  CONFIG  CPB = OFF
  CONFIG  CPD = OFF
  CONFIG  WRT0 = OFF
  CONFIG  WRT1 = OFF
  CONFIG  WRT2 = OFF
  CONFIG  WRT3 = OFF
  CONFIG  WRTC = OFF
  CONFIG  WRTB = OFF
  CONFIG  WRTD = OFF
  CONFIG  EBTR0 = OFF
  CONFIG  EBTR1 = OFF
  CONFIG  EBTR2 = OFF
  CONFIG  EBTR3 = OFF
  CONFIG  EBTRB = OFF
#ENDCONFIG

    OSCCON = $60   '4 mhz
    OSCTUNE.6 = 1  'PLL Enabled
   
DEFINE OSC 16    '16MHz (4X4 = 16)

    TRISB.4=0
'    ANSELH=0          'Not applicable to 18F2620
    ADCON1 = 15        'Disable ADC

    LED    VAR  PORTB.4  ' Assign name "LED" to 
         
    USERCOMMAND "DISPLED"    ; BUFFER{,COLON }
    USERCOMMAND "STRLEN"     ; BUFFER
    USERCOMMAND "RJUSTBUFF"  ; BUFFER
    
    TM_BIT        VAR BYTE BANK0
    TM_DAT        VAR BYTE BANK0
    TM_NAK        VAR BYTE BANK0       ;set to $80 if tx error occured
    TM_DIG        VAR BYTE BANK0
    TM_BRIGHT     VAR BYTE BANK0       ;display pwm level 0 to 7
    TM_COLON      VAR BYTE BANK0       ;display colon  0/1
    TM_TMP        VAR BYTE[2] BANK0
    str_len       VAR BYTE BANK0
    
    CMD_AUTO_ADDR CON $40 
    START_ADDR    CON $c0 
    NUM_DIGITS    CON 4                ;number of 7seg leds
    COLON_FLAG    CON $80 
    DISPLAY_ON    CON $88
    ;tm1637      DIO AND CLK NEED TO BE ON SAME PORT
    @TM_OUT_PORT = LATB       ;TM_DIO  OUT
    @TM_IN_PORT  = PORTB      ;TM_DIO  IN
    @TM_CLK      = 1          ;PIN
    @TM_DIO      = 0          ;PIN
    @TM_TRIS     = TRISB 
    
    BLINK         VAR BYTE
    LEDBUFF       VAR BYTE[NUM_DIGITS +1] 
    COUNTER       VAR BYTE
    
GOTO OVERASM
  
ASM  
DISPLED?B  macro BUFFER       
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    L?CALL _TM_DISP4 
    endm  
DISPLED?BC  macro BUFFER ,COLON      
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    MOVE?CB COLON ,_TM_COLON 
    L?CALL _TM_DISP4 
    endm    
DISPLED?BB  macro BUFFER ,COLON      
    movlw   low BUFFER
    movwf   FSR0L
    movlw   high BUFFER
    movwf   FSR0H 
    MOVE?BB COLON ,_TM_COLON 
    L?CALL _TM_DISP4 
    endm 
STRLEN?B  macro BUF      
    MOVE?CB high BUF, FSR0H ;load highbyte 
    MOVE?CB low  BUF, FSR0L ;load low byte
    L?CALL   STRlen
    endm
RJUSTBUFF?B  macro BUF      
    MOVE?CB high BUF, FSR0H ;load highbyte 
    MOVE?CB low  BUF, FSR0L ;load low byte
    MOVE?CB low  BUF, _TM_TMP  ;load low byte
    MOVE?CB HIGH  BUF, _TM_TMP+1  ;load low byte
    L?CALL  STRlen
    L?CALL  _strpad
    endm  
 
      
     
  
           
STRlen                     ;get buffer usage size 
    CLRF     _str_len    
str_tok_chr 
    ;MOVIW    FSR0 ++       ; Get character
    MOVF INDF0,W
    INFSNZ FSR0L
    incf   FSR0H
    btfsC    STATUS,Z     
    goto     exit_str_null ; EXIT ON Null char
    INCF     _str_len,F    ; not null so increment index
    goto     str_tok_chr
exit_str_null
    return 
  
 
_strpad           ;right justify by padding with spaces " "
    BANKSEL 0
    MOVLW   5
    ;ADDWF   _str_field_size,w  ;buffer size
    subwf   _str_len,f         ;tx string size 
    btfsc   STATUS, C          ;tx string size  gotcha
    goto    expd ;if positive difference then exit buffer overrun will occur  ;tx string size  gotcha
    comf    _str_len           ;the difference is number of spaces to SHIFT in
    btfsc   STATUS, Z
    goto    expd               ;if zero difference then exit
    moVLW    4  ;buffer size
    addwf   _TM_TMP,f         ;add  NUM_DIGITS to  addr of buffer
    ;btfsc   STATUS, C
    ;INCF    _STR_TMP+1,f
nxpd
    movf    _TM_TMP,w         ;low (addr of buffer + NUM_DIGITS )
    MOVWF   FSR0L
    movwf   FSR1L
    DECF    FSR0L,F             ;offset pointer 0
    ;btfsc   STATUS, C 
    ;DECF    FSR0H,F 
    movf    _TM_TMP+1,w        ;high (addr of buffer + NUM_DIGITS )
    MOVWF   FSR0H
    movwf   FSR1H
    MOVLW   4 
    movwf   _TM_BIT
nxby                            ;buffer shift right x 1
   ifdef TBLPTRL                ;fsr 
      movf  POSTDEC0, W         ;[pic18]
      MOVWF POSTDEC1
   else 
      MOVIW FSR0 --
      MOVWI FSR1 --
   endif
    DECFSZ  _TM_BIT,F
    GOTO    nxby
    movlw   0x20
    ifdef TBLPTRL               ;fsr 
      MOVWF POSTDEC1
    else 
      MOVWI FSR1 --
    endif
    DECFSZ  _str_len,F          ;need another one ?
    goto    nxpd
expd                            ;nah!
    BANKSEL 0
    return
SEG_val
    CHK?RP  _TM_TMP
    MOVWF   _TM_TMP
    CLRF _TM_TMP +1
    SUBLW   0x21
    btfsc   STATUS, C
    retlw   0   ;" "
    MOVF    _TM_TMP,W
    SUBLW   0x2f
    btfsc   STATUS, C
    retlw   64   ;"-"
    MOVF    _TM_TMP,W
    MOVLW   0X40
    SUBWF   _TM_TMP,W
    btfsC   STATUS, C
    GOTO    TM_ALPHA
    MOVF    _TM_TMP,W
    ANDLW   0X0F
    GOTO    TM_LU
TM_ALPHA 
    ANDLW   0xdf    ;ucase
    SUBLW   6
    btfsS   STATUS, C
    retlw   0       ;ERROR
    MOVLW   0X37
    SUBWF   _TM_TMP,W
    ANDLW   0xdf    ;ucase
TM_LU  
    addlw   LOW TABLE_START
    movwf   TBLPTRL
    rlcf    _TM_TMP +1 ,w
    addlw   HIGH TABLE_START 
    movwf   TBLPTRH
    movlw   UPPER TABLE_START 
    movwf   TBLPTRU
    tblrd   *+
    movf   TABLAT,w    
    return
      
  
TABLE_START 
 db    0X3F,6,0X5B,0X4F,0X66,0X6D,0X7D,7,0X7F,0X67,0X77 ,0X7C ,0X39 ,0X5E ,0X79 ,0X71                        
    
    
TM_START    
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK
    BSF    TM_OUT_PORT,TM_DIO
    NOP
    BCF    TM_OUT_PORT,TM_DIO
    NOP
    BCF    TM_OUT_PORT,TM_CLK
    NOP
    RETURN
    
TM_STOP 
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    BCF    TM_OUT_PORT,TM_DIO 
    NOP
    BSF    TM_OUT_PORT,TM_CLK 
    NOP
    BSF    TM_OUT_PORT,TM_DIO 
    NOP
    RETURN
    
TM_WRITE 
    MOVLW  8 
    CHK?RP _TM_BIT
    MOVWF  _TM_BIT
NXBT   
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP _TM_DAT
    BTFSS  _TM_DAT,0
    GOTO   TM_0
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_DIO 
    GOTO   TM_NB
TM_0    
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_DIO  
TM_NB   
    CHK?RP _TM_DAT
    RRCF    _TM_DAT,F
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK 
    CHK?RP _TM_BIT
    DECFSZ _TM_BIT,F
    GOTO   NXBT
    CHK?RP TM_OUT_PORT
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP TM_TRIS
    BSF    TM_TRIS,TM_DIO 
    CHK?RP TM_IN_PORT
    BTFSC  TM_IN_PORT,TM_DIO 
    BSF    _TM_NAK,7
    CHK?RP TM_OUT_PORT
    BSF    TM_OUT_PORT,TM_CLK 
    NOP
    NOP
    NOP
    NOP
    BCF    TM_OUT_PORT,TM_CLK 
    CHK?RP TM_TRIS 
    BCF    TM_TRIS ,TM_DIO 
    RST?RP
    RETURN
_TM_INIT
    CHK?RP  _TM_COLON
    CLRF    _TM_COLON
    CLRF    _TM_BRIGHT
    CHK?RP TM_TRIS
    BCF    TM_TRIS ,TM_DIO
    BCF    TM_TRIS ,TM_CLK
    RST?RP
    RETURN
    
_TM_DISP4 
    MOVLW   _CMD_AUTO_ADDR
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CLRF    _TM_NAK
    CALL    TM_START
    CALL    TM_WRITE
    CALL    TM_STOP
    MOVLW   _NUM_DIGITS          
    CHK?RP  _TM_DIG
    MOVWF   _TM_DIG
    MOVLW   _START_ADDR
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CALL    TM_START
    CALL    TM_WRITE 
NXDIG
    ;MOVIW   FSR0 ++
    MOVF INDF0,W
    INFSNZ FSR0L
    incf   FSR0H
    CALL    SEG_val
    CHK?RP  _TM_DAT
    IORWF   _TM_COLON ,W
    movwf   _TM_DAT
    CALL    TM_WRITE
    CHK?RP  _TM_DIG
    DECFSZ  _TM_DIG,F
    GOTO    NXDIG
    CALL    TM_STOP
    CHK?RP  _TM_BRIGHT 
    MOVF    _TM_BRIGHT ,W
    ANDLW   7
    IORLW   _DISPLAY_ON
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CALL    TM_START
    CALL    TM_WRITE
    CALL    TM_STOP
    RST?RP
    RETURN
    
    
_TM_DISP1     ; WRITES TO A DISP POSN TM_TMP HOLDS DATA FOR TM_DIG IS POSN  0-3
    CHK?RP  _TM_DAT
    MOVLW   _CMD_AUTO_ADDR
    MOVWF   _TM_DAT
    CALL    TM_START
    CALL    TM_WRITE
    CALL    TM_STOP
    MOVLW   _START_ADDR
    addwf   _TM_DIG,W
    CHK?RP  _TM_DAT
    MOVWF   _TM_DAT
    CALL    TM_START
    CALL    TM_WRITE 
    CHK?RP  _TM_TMP
    MOVF    _TM_TMP,W
    movwf   _TM_DAT
    CALL    TM_WRITE
    CALL    TM_STOP
    BANKSEL 0
    RETURN 
    
    
    
    
    
    
    
ENDASM  
OVERASM: 
    FOR COUNTER=0 TO 3
     TOGGLE LED 
       PAUSE 500
    next
    CALL TM_INIT
  BLINK=0  
    
 ALOOP:   
     TOGGLE LED  
    TM_BRIGHT=TM_BRIGHT-1
    if TM_BRIGHT>7 then TM_BRIGHT=7
    ARRAYWRITE LEDBUFF ,["B- ",#TM_BRIGHT]
   
    DISPLED  LEDBUFF,0
    
    
    PAUSE 500
    FOR COUNTER=0 TO 255
        ARRAYWRITE LEDBUFF ,[hex COUNTER,0]
        RJUSTBUFF  LEDBUFF 
        DISPLED  LEDBUFF,0
        PAUSE 50
    NEXT
    FOR COUNTER=0 TO 255
        IF  !(COUNTER//20) THEN BLINK = TM_COLON ^ $80
        ARRAYWRITE LEDBUFF ,[sdec COUNTER,0]
        RJUSTBUFF  LEDBUFF 
        DISPLED  LEDBUFF,BLINK
        PAUSE 50
    NEXT
    goto ALOOP

**richard** · - 18th October 2018, 04:14

WOW! FINALLY, IT HAPPENED!!

The TM1637 LED display module came alive!!!
I used your revised code for 18F devices and after I made a few changes in the CONFIG section, the compilation for 18F2620 was successful.

very good. you would have to wonder why the 12f1840 did not work

I changed the Osc speed from 32 to 16MHz. Later, I tried the code at 8MHz and 4MHz. It works beautifully at those speeds too.

the code works up t0 64mhz and can write the 4 digits in less than 50uS

Thread: How to use TM1637 chip for LED Display?

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