Issues sending and receiving data

[PaulMaker]

Hi guys,

I'm trying to send/receive data between 2 PICs on the same circuit.
The first one (16F1508) is sending data with debug command.

INCLUDE "modedefs.bas" 

DEFINE DEBUG_REG PORTA             ' Set Debug pin port
DEFINE DEBUG_BIT 2                ' Set Debug pin bit
DEFINE DEBUG_BAUD 2400            ' Set Debug baud rate 
DEFINE DEBUG_MODE 0                ' Set Debug mode: 0 = true, 1 = inverted


PreAmble     CON     $A5


debug PreAmble,$af,$c2,$b5,$ef,13,10

The second one (16F1503) is receiving the data with debugin command.

INCLUDE "modedefs.bas" 

DEFINE DEBUG_REG PORTC             ' Set Debug pin port
DEFINE DEBUG_BIT 2                ' Set Debug pin bit
DEFINE DEBUG_BAUD 2400            ' Set Debug baud rate 
DEFINE DEBUG_MODE 0                ' Set Debug mode: 0 = true, 1 = inverted


DEFINE DEBUGIN_REG PORTA        ' Set Debugin pin port 
DEFINE DEBUGIN_BIT 1            ' Set Debugin pin bit  
DEFINE DEBUGIN_BAUD 2400        ' Set Debugin baud rate (same as Debug baud) 
DEFINE DEBUGIN_MODE 0            ' Set Debugin mode: 0 = true, 1 = inverted 


Main:
DEBUGIN 1000,timeoutlabel,[WAIT("$af"),DAT1,DAT2,DAT3]
pause 3000

IF DAT1=$c2 THEN
GOTO SELECTION
ENDIF



goto main


timeoutlabel:
debug DEC 99,DAT1,DAT2,DAT3,13,10
pause 3000


goto main

The data validation fails and the code jumps to the timeout label.

The timeout label is sending the received information out for troubleshooting purposes.
For troubleshooting I'm using a Microchip Pickit serial analyzer.

The information sent is different from the information received.

This is the data sent from PIC #1 and captured with the analyzer:

[00][A5][AF][C2][B5][EF][0D][0A]

And this is the data sent from PIC #2 (when in timeoutlabel) and captured with the analyzer:

 [4E][4E][BF][79][0D][0A][00]

Why is the data different? The only data that seems to be correct are the carriage return bytes.
What am I doing wrong?

Thanks

[Ioannis]

I do not see a loop in the sending device. Seems it sends the data once and then stops.

So the receiving device, if fails to receive first time correct data, loops in the timeout sub.

Then spits out the data that are randomly stored in the variables, since you do not have a CLEAR command on the top of your program. CLEAR will ensure all variables are set to zero.

The PAUSE 3000 are not needed I guess, since you have a 1 sec timeout.

Ioannis.

[PaulMaker]

Greetings Ioannis,

thank you so much for your help.

The sending device is actually running on a loop to troubleshoot the issue. I failed to copy that in here but it's something like this:

main:

debug PreAmble,$af,$c2,$b5,$ef,13,10


pause 3000


goto main

The receiving pic is also on a loop and that's the reason for the pause 3000 before going back to Main.

[Ioannis]

You also have to disable the analog inputs of port A, set by default on PIC reset, by clearing the ANSELA register.

If you drive the output as in the sender program, then the port is set as digital output. Still I would disable the analog function. But as input it will operate as Analog input, not digital.

Also get rid of the PAUSE 3000. They offer nothing really useful.

Ioannis

[amgen]

...... [WAIT("$af"),DAT1,DAT2,DAT3]........ [WAIT($af),DAT1,DAT2,DAT3]

[PaulMaker]

Greetings all,

thanks for the replies.

Regarding the I/O setup, I have included the "INCLUDE "ALLDIGITAL.pbp"" on both receiver and sender codes.

And even with the "[WAIT($af),DAT1,DAT2,DAT3]" modification, I still get the wrong data on the receiver PIC.

Any additional thoughts?

Thank you so much.

[richard]

Any additional thoughts?

my thoughts-
code snippets are a waste of time, a minimal, complete and verifiable example MCVE gets results
https://stackoverflow.com/help/minim...ucible-example

[PaulMaker]

Greetings Richard,

that makes total sense, sorry for that.

Here is the code being used to test/troubleshoot the issue...

The sending PIC triggers COM pin high/low before sending the data.
The receiving PIC detects the COM trigger with IOC interrupt and starts listening.
This part of the code is working since it's detecting the trigger and starts listening.
The thing that is not working is the data reception correctly.

Send pic code

'****************************************************************'*  Name    : 16F1508_Send.PBP                                  *
'*            PORTA.2 CONNECTED TO PORTA.1 ON RECEIVING PIC     *
'****************************************************************
'
;----[16F1508 Hardware Configuration]-------------------------------------------
#IF __PROCESSOR__ = "16F1508"
  #DEFINE MCU_FOUND 1
#CONFIG
cfg1 = _FOSC_INTOSC           ; INTOSC oscillator: I/O function on CLKIN pin
cfg1&= _WDTE_OFF              ; WDT disabled
cfg1&= _PWRTE_OFF             ; PWRT disabled
cfg1&= _MCLRE_OFF             ; MCLR/VPP pin function is digital input
cfg1&= _CP_OFF                ; Program memory code protection is disabled
cfg1&= _BOREN_OFF             ; Brown-out Reset disabled
cfg1&= _CLKOUTEN_OFF          ; CLKOUT function is disabled. I/O or oscillator function on the CLKOUT pin
cfg1&= _IESO_OFF              ; Internal/External Switchover Mode is disabled
cfg1&= _FCMEN_OFF             ; Fail-Safe Clock Monitor is disabled
  __CONFIG _CONFIG1, cfg1


cfg2 = _WRT_OFF               ; Write protection off
cfg2&= _STVREN_OFF            ; Stack Overflow or Underflow will not cause a Reset
cfg2&= _BORV_LO               ; Brown-out Reset Voltage (Vbor), low trip point selected.
cfg2&= _LPBOR_OFF             ; Low-Power BOR is disabled
cfg2&= _LVP_OFF               ; High-voltage on MCLR/VPP must be used for programming
  __CONFIG _CONFIG2, cfg2


#ENDCONFIG


#ENDIF


;----[Verify Configs have been specified for Selected Processor]----------------
;       Note: Only include this routine once, after all #CONFIG blocks
#IFNDEF MCU_FOUND
  #ERROR "No CONFIGs found for [" + __PROCESSOR__ +"]"
#




DEFINE OSC 16                               ' Let PBP clock speed will be 16MHz
OSCCON = %01111011                          ' Use internal oscillator and set to 16MHz


OPTION_REG.7 = 0                            ' Enable individual control of weak pull-ups
WPUA.0 = 0                                  ' Disable weak pull-up on RA0
WPUA.1 = 0                                  ' Disable weak pull-up on RA1
WPUA.2 = 0                                  ' Disable weak pull-up on RA2
WPUA.3 = 0                                  ' Disable weak pull-up on RA3
WPUA.4 = 1                                  ' Enable weak pull-up on RA4
WPUA.5 = 1                                  ' Enable weak pull-up on RA5


DACCON0.7 = 0                               ' Disable DAC
CM1CON0.7 = 0                               ' Disable comparator 1
CM2CON0.7 = 0                               ' Disable comparator 2


TRISA = %00000000                          
TRISB = %00000000 
TRISC = %00000000      


'*****************************************************************************


INCLUDE "ALLDIGITAL.pbp"
DEFINE SHOWDIGITAL 1


INCLUDE "modedefs.bas" 


DEFINE DEBUG_REG PORTA 			' Set Debug pin port
DEFINE DEBUG_BIT 2				' Set Debug pin bit
DEFINE DEBUG_BAUD 2400			' Set Debug baud rate 
DEFINE DEBUG_MODE 0				' Set Debug mode: 0 = true, 1 = inverted


'*****************************************************************************
'PORTS & PINS 


COMMTX	    	VAR		PORTA.2	
MESLED	    	VAR		PORTB.5		'MESSAGE LED


PreAmble 		CON 	$A5    


'*****************************************************************************
INIT:


PORTA=%00000000
PORTB=%00000000
PORTC=%00000000


GOTO START


'*****************************************************************************
START:


HIGH INTLED
HIGH COMMTX
PAUSE 500
LOW COMMTX
LOW INTLED


PAUSE 200


HIGH MESLED


debug PreAmble,$af,$c2,$b5,$ef,13,10


PAUSE 500
LOW MESLED


PAUSE 4000


GOTO START


'------------------------------------------------------------------------------

Receive pic code

'****************************************************************'*  Name    : 16F1503_Receive.PBP                               *
'*            PORTA.1 CONNECTED TO PORTA.2 ON SENDING PIC       *
'****************************************************************
'
;----[16F1503 Hardware Configuration]-------------------------------------------
#IF __PROCESSOR__ = "16F1503"
  #DEFINE MCU_FOUND 1
#CONFIG
cfg1 = _FOSC_INTOSC           ; INTOSC oscillator: I/O function on CLKIN pin
cfg1&= _WDTE_OFF              ; WDT disabled
cfg1&= _PWRTE_OFF             ; PWRT disabled
cfg1&= _MCLRE_OFF             ; MCLR/VPP pin function is digital input
cfg1&= _CP_OFF                ; Program memory code protection is disabled
cfg1&= _BOREN_OFF             ; Brown-out Reset disabled
cfg1&= _CLKOUTEN_OFF          ; CLKOUT function is disabled. I/O or oscillator function on the CLKOUT pin
  __CONFIG _CONFIG1, cfg1


cfg2 = _WRT_OFF               ; Write protection off
cfg2&= _STVREN_OFF            ; Stack Overflow or Underflow will not cause a Reset
cfg2&= _BORV_LO               ; Brown-out Reset Voltage (Vbor), low trip point selected.
cfg2&= _LPBOR_OFF             ; Low-Power BOR is disabled
cfg2&= _LVP_OFF               ; High-voltage on MCLR/VPP must be used for programming
  __CONFIG _CONFIG2, cfg2


#ENDCONFIG


#ENDIF


;----[Verify Configs have been specified for Selected Processor]----------------
;       Note: Only include this routine once, after all #CONFIG blocks
#IFNDEF MCU_FOUND
  #ERROR "No CONFIGs found for [" + __PROCESSOR__ +"]"
#ENDIF


'*****************************************************************************


DEFINE OSC 16                               ' Let PBP clock speed will be 16MHz
OSCCON = %01111011                          ' Use internal oscillator and set to 16MHz


OPTION_REG.7 = 0                            ' Enable individual control of weak pull-ups
WPUA.0 = 0                                  ' Disable weak pull-up on RA0
WPUA.1 = 0                                  ' Disable weak pull-up on RA1
WPUA.2 = 0                                  ' Disable weak pull-up on RA2
WPUA.3 = 0                                  ' Disable weak pull-up on RA3
WPUA.4 = 0                                  ' Disable weak pull-up on RA4
WPUA.5 = 0                                  ' Disable weak pull-up on RA5


DACCON0.7 = 0                               ' Disable DAC
CM1CON0.7 = 0                               ' Disable comparator 1
CM2CON0.7 = 0                               ' Disable comparator 2


TRISA = %00001010                           ' Set RA1-RA3 as inputs
TRISC = %00000000                           ' Set RC port as output


'*****************************************************************************


INCLUDE "ALLDIGITAL.pbp"
DEFINE SHOWDIGITAL 1


INCLUDE "DT_INTS-14.bas"     ' Base Interrupt System
INCLUDE "ReEnterPBP.bas"     ' Include if using PBP interrupts


INCLUDE "modedefs.bas" 


DEFINE DEBUG_REG PORTA 			' Set Debug pin port
DEFINE DEBUG_BIT 3				' Set Debug pin bit
DEFINE DEBUG_BAUD 2400			' Set Debug baud rate 
DEFINE DEBUG_MODE 0				' Set Debug mode: 0 = true, 1 = inverted


DEFINE DEBUGIN_REG PORTA		' Set Debugin pin port 
DEFINE DEBUGIN_BIT 1			' Set Debugin pin bit  
DEFINE DEBUGIN_BAUD 2400		' Set Debugin baud rate (same as Debug baud) 
DEFINE DEBUGIN_MODE 0			' Set Debugin mode: 0 = true, 1 = inverted  


'*****************************************************************************
;____[ For 12F/16F only - Interrupt Context save locations]_________________
;-- Place a copy of these variables in your Main program -------------------
;--   The compiler will tell you which lines to un-comment                --
;--   Do Not un-comment these lines                                       --
;---------------------------------------------------------------------------
;wsave   VAR BYTE    $20     SYSTEM      ' location for W if in bank0
;wsave   VAR BYTE    $70     SYSTEM      ' alternate save location for W 
                                         ' if using $70, comment wsave1-3


' --- IF any of these three lines cause an error ?? ------------------------
'       Comment them out to fix the problem ----
' -- Which variables are needed, depends on the Chip you are using -- 
;wsave1  VAR BYTE    $A0     SYSTEM      ' location for W if in bank1
;wsave2  VAR BYTE    $120    SYSTEM      ' location for W if in bank2
;wsave3  VAR BYTE    $1A0    SYSTEM      ' location for W if in bank3
' --------------------------------------------------------------------------
'https://www.picbasic.co.uk/forum/showthread.php/3251-Instant-Interrupts-Revisited/page7?highlight=DT%27s+instant+interrupts
'https://www.picbasic.co.uk/forum/showthread.php/3251-Instant-Interrupts-Revisited/page16?highlight=DT%27s+instant+interrupts
'Open the DT_INTS-14.bas file and comment out the wsave lines. 
'The 675 doesn't have any usable RAM in banks 1,2 or 3


'*****************************************************************************


INTCON.3=1
IOCAP.1=1 	     'POSITIVE EDGE @ A1 ON
IOCAN=%0		 'NEGATIVE EDGE OFF


'page 106


'*****************************************************************************
'---[INT - interrupt handler]---------------------------------------------------
ASM
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler  IOC_INT,    _IOCinterrupts,    PBP,  yes
endm
INT_CREATE               ; Creates the interrupt processor
ENDASM


@ INT_ENABLE IOC_INT


'*****************************************************************************
'PORTS & PINS 
	
INTLED	    VAR		PORTC.3		'INTERRUPT LED		
MESLED	    VAR		PORTC.4		'MESSAGE LED


'*****************************************************************************


DAT1        VAR     BYTE	'
DAT2        VAR     BYTE	'
DAT3        VAR     BYTE	'
CT			VAR		BYTE	'


'*****************************************************************************
INIT:


PORTC=%000000


GOTO START


'------------------------------------------------------------------------------
START:


LOW INTLED
LOW MESLED


GOTO START


'------------------------------------------------------------------------------
IOCinterrupts:


@   INT_DISABLE IOC_INT 


HIGH INTLED


PAUSE 500


DEBUGIN 1000,timeoutlabel,[WAIT($af),DAT1,DAT2,DAT3]


PAUSE 200


pause 500


low INTLED


PAUSE 500


IF DAT1=$c2 THEN
GOTO PROGSEL
ENDIF


'RETURN TO PROGRAM
IOCAF=%0
@ INT_ENABLE IOC_INT
@ INT_RETURN


;-------------------------------------------------------------------------------
timeoutlabel:


low INTLED


HIGH MESLED
debug DEC 99,DAT1,DAT2,DAT3,13,10 'Message confirming bad reception


pause 1000
low MESLED


'RETURN TO PROGRAM
IOCAF=%0
@ INT_ENABLE IOC_INT
@ INT_RETURN


;-------------------------------------------------------------------------------
PROGSEL


debug DEC 09,DAT1,DAT2,DAT3,13,10 'Message confirming reception


for ct=0 to 10
toggle INTLED
toggle MESLED
pause 500
next ct




'RETURN TO PROGRAM
IOCAF=%0
@ INT_ENABLE IOC_INT
@ INT_RETURN
;-------------------------------------------------------------------------------

Thanks for the help

[amgen]

.... also maybe.....

PreAmble CON $A5
debug PreAmble,$af,$c2,$b5,$ef,13,10

PreAmble CON $A5


,$af,$c2,$b5,$ef,13,10 is equal to 175,194,181,239,13,10 .... so ... debug 165,175,194,181,239,13,10.... or debug HEX 165,175,194,181,239,13,10

then.... Main:
DEBUGIN 1000,timeoutlabel,[WAIT(165),DAT1,DAT2,DAT3]
pause 3000
or
Main:
DEBUGIN 1000,timeoutlabel,[WAIT(HEX $AF),$DAT1,$DAT2,$DAT3]
pause 3000....
have to know what exactly characters are sending and receiving... I would output to a serial terminal to see if what you are sending is what you think you are sending

[PaulMaker]

Greetings amgen,

thanks for the help,

This is the data sent from PIC #1 and captured with the analyzer:

[00][A5][AF][C2][B5][EF][0D][0A]

And this is the data sent from PIC #2 (when in timeoutlabel) and captured with the analyzer:

 [4E][4E][BF][79][0D][0A][00]

[amgen]

your sending capture looks good. Handling the receive, the debug in may or may not filter how you want... play with that some because if receiving HEX, that is 2 bytes to make into 1 byte value of DAT etc... ???? ... can also dictate (if it is not the default) 2 digits for the hex... HEX2
maybe.... DEBUGIN 1000,timeoutlabel,[WAIT("AF"),$DAT1,$DAT2,$DAT3].... or DEBUGIN 1000,timeoutlabel,[WAIT(HEX2 AF),$DAT1,$DAT2,$DAT3].... or DEBUGIN 1000,timeoutlabel,[WAIT(HEX2 "AF"),$DAT1,$DAT2,$DAT3]
.
.
. Thought of 1 more thing.... add a temporary serout or debug and send to your capture or ser terminal 1 received character at a time to easily see what you are receiving

[Ioannis]

I do not have that chip, so can you check if this code works please?

'****************************************************************'*  Name    : 16F1503_Receive.PBP                               *
'*            PORTA.1 CONNECTED TO PORTA.2 ON SENDING PIC       *
'****************************************************************
'
;----[16F1503 Hardware Configuration]-------------------------------------------
#IF __PROCESSOR__ = "16F1503"
  #DEFINE MCU_FOUND 1
#CONFIG
cfg1 = _FOSC_INTOSC           ; INTOSC oscillator: I/O function on CLKIN pin
cfg1&= _WDTE_OFF              ; WDT disabled
cfg1&= _PWRTE_OFF             ; PWRT disabled
cfg1&= _MCLRE_OFF             ; MCLR/VPP pin function is digital input
cfg1&= _CP_OFF                ; Program memory code protection is disabled
cfg1&= _BOREN_OFF             ; Brown-out Reset disabled
cfg1&= _CLKOUTEN_OFF          ; CLKOUT function is disabled. I/O or oscillator function on the CLKOUT pin
  __CONFIG _CONFIG1, cfg1


cfg2 = _WRT_OFF               ; Write protection off
cfg2&= _STVREN_OFF            ; Stack Overflow or Underflow will not cause a Reset
cfg2&= _BORV_LO               ; Brown-out Reset Voltage (Vbor), low trip point selected.
cfg2&= _LPBOR_OFF             ; Low-Power BOR is disabled
cfg2&= _LVP_OFF               ; High-voltage on MCLR/VPP must be used for programming
  __CONFIG _CONFIG2, cfg2


#ENDCONFIG


#ENDIF


;----[Verify Configs have been specified for Selected Processor]----------------
;       Note: Only include this routine once, after all #CONFIG blocks
#IFNDEF MCU_FOUND
  #ERROR "No CONFIGs found for [" + __PROCESSOR__ +"]"
#ENDIF


'*****************************************************************************


DEFINE OSC 16                               ' Let PBP clock speed will be 16MHz
OSCCON = %01111011                          ' Use internal oscillator and set to 16MHz


OPTION_REG.7 = 0                            ' Enable individual control of weak pull-ups
WPUA.0 = 0                                  ' Disable weak pull-up on RA0
WPUA.1 = 0                                  ' Disable weak pull-up on RA1
WPUA.2 = 0                                  ' Disable weak pull-up on RA2
WPUA.3 = 0                                  ' Disable weak pull-up on RA3
WPUA.4 = 0                                  ' Disable weak pull-up on RA4
WPUA.5 = 0                                  ' Disable weak pull-up on RA5


DACCON0.7 = 0                               ' Disable DAC
CM1CON0.7 = 0                               ' Disable comparator 1
CM2CON0.7 = 0                               ' Disable comparator 2


TRISA = %00001010                           ' Set RA1-RA3 as inputs
TRISC = %00000000                           ' Set RC port as output


'*****************************************************************************


INCLUDE "ALLDIGITAL.pbp"
DEFINE SHOWDIGITAL 1


INCLUDE "DT_INTS-14.bas"     ' Base Interrupt System
INCLUDE "ReEnterPBP.bas"     ' Include if using PBP interrupts


INCLUDE "modedefs.bas" 


DEFINE DEBUG_REG PORTA 			' Set Debug pin port
DEFINE DEBUG_BIT 3				' Set Debug pin bit
DEFINE DEBUG_BAUD 2400			' Set Debug baud rate 
DEFINE DEBUG_MODE 0				' Set Debug mode: 0 = true, 1 = inverted


DEFINE DEBUGIN_REG PORTA		' Set Debugin pin port 
DEFINE DEBUGIN_BIT 1			' Set Debugin pin bit  
DEFINE DEBUGIN_BAUD 2400		' Set Debugin baud rate (same as Debug baud) 
DEFINE DEBUGIN_MODE 0			' Set Debugin mode: 0 = true, 1 = inverted  


'*****************************************************************************
;____[ For 12F/16F only - Interrupt Context save locations]_________________
;-- Place a copy of these variables in your Main program -------------------
;--   The compiler will tell you which lines to un-comment                --
;--   Do Not un-comment these lines                                       --
;---------------------------------------------------------------------------
;wsave   VAR BYTE    $20     SYSTEM      ' location for W if in bank0
;wsave   VAR BYTE    $70     SYSTEM      ' alternate save location for W 
                                         ' if using $70, comment wsave1-3


' --- IF any of these three lines cause an error ?? ------------------------
'       Comment them out to fix the problem ----
' -- Which variables are needed, depends on the Chip you are using -- 
;wsave1  VAR BYTE    $A0     SYSTEM      ' location for W if in bank1
;wsave2  VAR BYTE    $120    SYSTEM      ' location for W if in bank2
;wsave3  VAR BYTE    $1A0    SYSTEM      ' location for W if in bank3
' --------------------------------------------------------------------------
'https://www.picbasic.co.uk/forum/showthread.php/3251-Instant-Interrupts-Revisited/page7?highlight=DT%27s+instant+interrupts
'https://www.picbasic.co.uk/forum/showthread.php/3251-Instant-Interrupts-Revisited/page16?highlight=DT%27s+instant+interrupts
'Open the DT_INTS-14.bas file and comment out the wsave lines. 
'The 675 doesn't have any usable RAM in banks 1,2 or 3


'*****************************************************************************


INTCON.3=1
IOCAP.1=1 	     'POSITIVE EDGE @ A1 ON
IOCAN=%0		 'NEGATIVE EDGE OFF


'page 106


'*****************************************************************************
'---[INT - interrupt handler]---------------------------------------------------
'ASM
'INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
'        INT_Handler  IOC_INT,    _IOCinterrupts,    PBP,  yes
'endm
'INT_CREATE               ; Creates the interrupt processor
'ENDASM
'
'
'@ INT_ENABLE IOC_INT


'*****************************************************************************
'PORTS & PINS 
	
INTLED	    VAR		PORTC.3		'INTERRUPT LED		
MESLED	    VAR		PORTC.4		'MESSAGE LED


'*****************************************************************************


DAT1        VAR     BYTE	'
DAT2        VAR     BYTE	'
DAT3        VAR     BYTE	'
CT			VAR		BYTE	'


'*****************************************************************************
INIT:


PORTC=%000000


GOTO START


'------------------------------------------------------------------------------
START:


LOW INTLED
LOW MESLED

DEBUGIN 1000,timeoutlabel,[WAIT($af),DAT1,DAT2,DAT3]

GOTO START

timeoutlabel:
    low INTLED


    HIGH MESLED
    debug "Bad data",13,10 'Message confirming bad reception

    pause 1000
    low MESLED
goto START


''------------------------------------------------------------------------------
'IOCinterrupts:


'@   INT_DISABLE IOC_INT 


'HIGH INTLED


'PAUSE 500


'DEBUGIN 1000,timeoutlabel,[WAIT($af),DAT1,DAT2,DAT3]


'PAUSE 200


'pause 500


'low INTLED


'PAUSE 500


'IF DAT1=$c2 THEN
'GOTO PROGSEL
'ENDIF


''RETURN TO PROGRAM
'IOCAF=%0
'@ INT_ENABLE IOC_INT
'@ INT_RETURN


';-------------------------------------------------------------------------------
'timeoutlabel:


'low INTLED


'HIGH MESLED
'debug DEC 99,DAT1,DAT2,DAT3,13,10 'Message confirming bad reception


'pause 1000
'low MESLED


''RETURN TO PROGRAM
'IOCAF=%0
'@ INT_ENABLE IOC_INT
'@ INT_RETURN


;-------------------------------------------------------------------------------
PROGSEL


debug DEC 09,DAT1,DAT2,DAT3,13,10 'Message confirming reception


for ct=0 to 10
toggle INTLED
toggle MESLED
pause 500
next ct




'RETURN TO PROGRAM
'IOCAF=%0
'@ INT_ENABLE IOC_INT
'@ INT_RETURN
;-------------------------------------------------------------------------------

Ioannis

[richard]

i don't see this working , porta.3 is input only

Receive pic code

DEFINE DEBUG_REG PORTA 			' Set Debug pin port
DEFINE DEBUG_BIT 3				' Set Debug pin bit
DEFINE DEBUG_BAUD 2400			' Set Debug baud rate 
DEFINE DEBUG_MODE 0				' Set Debug mode: 0 = true, 1 = inverted

the concept of reading a serial transmission in an interrupt routine triggered by the start bit is badly flawed.
by the time the isr's bit-banged reception routine is activated the start bit has been lost and you will just read in a bunch of framing errors

[richard]

hard to see the red bits doing anything of value except to cause framing errors

you could add the blue bits to prevent framing errors @ startup

COMMTX            VAR        PORTA.2    MESLED            VAR        PORTB.5        'MESSAGE LED




PreAmble         CON     $A5    




'*****************************************************************************
INIT:




PORTA=000000
PORTB=000000
PORTC=000000
HIGH COMMTX
pause 10
GOTO START




'*****************************************************************************
START:




HIGH INTLED
HIGH COMMTX
PAUSE 500
LOW COMMTX
LOW INTLED




PAUSE 200




HIGH MESLED




debug PreAmble,$af,$c2,$b5,$ef,13,10




PAUSE 500
LOW MESLED




PAUSE 4000




GOTO START

if you use a viable pin on the rx unit it for debug will work , its not a way i would recommend

[PaulMaker]

Greetings everyone,

first of all, thank you so much for your help.
Will try your suggestions tonight and give feedback.

@Richard, just to explain...the red bits are there only to trigger the IOC on the receiver side so that it knows when it needs to start listening.
The reason is because the receiver PIC will do a lot of tasks and will only stop to pay attention to the RX pin when the IOC is triggered.
The IOC and RX pins are defined as the same pin to save an I/O pin on both sender and received PICs.


Best regards
Rui

[Ioannis]

If you instist on using ISR for the USART receiver, why not use the USART Interrupt directly? It will not work otherwise as Richard noted.

Test your circuit and logic of the communication first with no interrupts and then decide what to do next.

Ioannis

[PaulMaker]

Greetings Ioannis,

Yes, I know...

the problem is that, although the TX PIC 16F1508 is equipped with a EUSART module, the receiver PIC 16F1503 is not
The IOC was a workaround that i came up with to trigger the debugin command on the RX PIC.

Best regards

[amgen]

wow, no hardware usart is serious..... your 1503 has mssp interrupt..... if you can make all that work, you are very skilled indeed !

[Ioannis]

Then you have to run a fast loop and make sure you won't miss any byte.

Are you sure you cannot change that 1503?

Ioannis

[PaulMaker]

Hi guys,

sorry for the late reply...

After some testing, I decided to change my 16F1503 receiver PIC to a 16F1508 which is equipped with an USART module. It's much easier to implement this way.

Thank you all for the support!