Simplest hardware and code to blink a LED with PIC18F4620

[BrianT]

I have some boards I need to test before committing labour and some expensive peripherals. I have changed the thread name as the older one was getting off the track I thought.

I have partly loaded just the bare minimum parts to implement the attached circuit on my target PCB and the LEDs do not flash. To decide whether the problem is my code or a PCB fault, I have built this circuit on two different proto boards. They don't flash the LEDs either so I suspect my code. I also built up a second target PCB so I now have four copies of the problem which I am sure will be solved with some 'ah-ha' moment from one of the smart PBP3 forum members.

Numerous forum users have made suggestions, for which I thank you, but the code is still no go.

OSCTUNE is of no consequence. I do not care if the clock is +/- 50% so I think I can ignore OSCTUNE. LED brightness truly does not matter at this point and believe me 1k is plenty bright enough for indoor close range use.

OSCCON is vital. If you want to use any of the frequencies listed in OSCCON (except 31 KHz), you must have OSCCON bits 0 & 1 set for "Internal Oscillator Block" which is 1x. If these bits are 0 0 then the PIC expects a clock to be supplied on RA6 pin 13 (40 pin DIP variant).

I have used an oscilloscope to check for ClkOut on pin RA.7 and to ensure the reset line is +5. The chip has both power and ground pins correctly supplied.

I am using PBP3.0.7.4 MCSPX 5.0.0.5 MPASM

Any assistance greatly appreciated.
Cheers
BrianT

code:
data @0, "Wet ver a 2 Nov 2013 "
'Internal 8 MHz clock. INTIO1 Internal Oscillator with FOSC/4 output
'on RA6 and I/O on RA7 - I wish!.
'******************* Configuration fuses ***************************
' Device = PIC18F4620
' Osc = INTIO1 (ClkOut), FSCM = En, Int Ext Switch = En, PwrUpTmr = En,
' BrownOut = Dis, BrwnOut Volt = 2, WDT = Dis, WDT PostScaler = 512
' CCP2 on RC1, PortB Rst = Digital, LowPwr Tmr1 Osc = Higher power,
' MCLR = Reset, Stack Over/Under = En, LowVoltProg = Dis,
' Enhanced CPU = Dis, ALL FOLLOWING set to Not Protected.


'********************** DATA and DEFINES ***************************
DEFINE OSC 8
'Select INTIO1 (ClkOut) in the configuration menu at programming.
'Use OSCCON to select frequency & select internal oscillator block
'Use CRO to see if any ClkOut visible on Osc2/ClkOut pin 14(40) or 31(44)

Initialise:

LED1 var PORTE.1 'LATE.1 does not work either
LED2 var PORTE.2 'LATE.2 does not work either

TRISE = %00001000 'make sure PSP is OFF & MCLR active
PORTE = %00001000 '

OSCCON = %11111110 ' 8 MHz Internal Osc Block
' 0------- IDLEN 0 = enters SLEEP on Sleep command. Board draws 4 uA
' 1------- IDLEN 1 = enters IDLE on Sleep command and draws 550 uA
' -111---- IRCF <2:0> Int Osc freq select 111 = 8 MHz
' -110---- IRCF <2:0> Int Osc freq select 110 = 4 MHz
' -101---- 2 MHz
' -100---- 1 MHz
' -011---- 500 kHz
' -010---- 250 kHz
' -010---- 125 kHz
' -000---- 31 kHz
' ----0--- OSTS Osc Startup Status - read only - ignore
' -----0-- IOFS IntOsc Freq Stable - read only - ignore
' ------00 System Clock Select 00 = Primary Osc = external xtal
' ------01 Secondary (Timer1) oscillator
' ------1x Internal oscillator block.

WDTCON = %00000001 ' enables SWDT - needs WDT OFF in config
' xxxxxxx1 SWDTEN software controlled WDT enabled
ADCON0 = %00000000 ' ADC OFF
' xx0000-- CH<3:0> select analog channels
' ------0- 1 = Go, 0 = Done
' -------0 1 = ADC ON, 0 = ADC OFF
ADCON1 = %00001111 'VRef = Vdd, Vss, All ports digital
' configures all digital
' 00------ Unimplemented
' --00---- VCFG<1:0> Select Vcc & Gnd as ADC references
' ----0110 PCFG<3:0> A/D Port configuration see "register 19-1"
CMCON = %00000111 ' Comparators OFF
' 00------ No comparator outputs
' --00---- No inversion on outputs
' ----0--- Vin to pins AN0 & AN1
' -----111 Comparators OFF
MainLoop:
High LED1 '
high led2

Pause 10 '

Low LED1 '
low led2

Pause 10 '

Goto mainloop '

End

endcode:

[richard]

i'm not sure how you pgm your chip but since you are using pbp3 you should insert your config fuses in the pgm

look at PIC18F46K20.INFO in the pbp3 device_reference folder for more info.
just let pbp look after the wdt unless you really need to change it.

until you get the config fuses right nothing will work right.

#CONFIG
CONFIG FOSC = INTIO67
CONFIG PWRT = ON
CONFIG BOREN = ON
CONFIG DEBUG = OFF
CONFIG WDTEN = ON
CONFIG XINST = OFF
CONFIG PBADEN = OFF
CONFIG MCLRE = ON
CONFIG STVREN = ON
CONFIG LVP = OFF
#ENDCONFIG

oscon=$70 will give you a 8mhz clk $60 $4 MHz
you need a
DEFINE OSC 8 or whatever if the clk is not 4mhz
if you are unsure about switching off the analog features have a look at the
ALLDIGITAL.PBP file by daryl taylor thah can be found in this forum

[richard]

I hope you don't expect to see the led flash with naked eyes ,
with a pause 10 the led will just look a bit dim, to view with eyes try pause 500 at least

[BrianT]

Hi Richard,
Thanks for your time in looking at this. I am using a scope so 10 mS is very visible. I use the melabs U2 USB programmer and manually set the config fuses as per the table at the top of my program. I force all pins to be digital via the ADCON1 statement ADCON1 = %00001111.

In the attached code, I have followed your advice and loaded the device reference file then removed the ';' character where appropriate to activate that line. Still no joy, nothing on the ClkOut line or the LED lines. Reset is pulled high by 1k to 5V and there is +5 to both Vdd pins.

I have 3 spaces before #CONFIG - is this acceptable or must #CONFIG appear in column 1

#CODE
data @0, "Wet ver b 3 Nov 2013 "
'Internal 8 MHz clock. INTIO1 Internal Oscillator with FOSC/4 output
'on RA6 and I/O on RA7.
'******************* Configuration fuses ***************************
' Device = PIC18F4620
' Osc = INTIO1 (ClkOut), FSCM = En, Int Ext Switch = En, PwrUpTmr = En,
' BrownOut = Dis, BrwnOut Volt = 2, WDT = Dis, WDT PostScaler = 512
' CCP2 on RC1, PortB Rst = Digital, LowPwr Tmr1 Osc = Higher power,
' MCLR = Reset, Stack Over/Under = En, LowVoltProg = Dis,
' Enhanced CPU = Dis, ALL FOLLOWING set to Not Protected.
'''''''''''''''''''''''''' ex Richard ''''''''''''''''''''''''''''''

#CONFIG

; Oscillator Selection bits
CONFIG OSC = INTIO7 ;Internal oscillator block, CLKOUT function on RA6, port function on RA7
; CONFIG OSC = INTIO67 ;Internal oscillator block, port function on RA6 and RA7
; CONFIG OSC = RCIO6 ;External RC oscillator, port function on RA6
; CONFIG OSC = HSPLL ;HS oscillator, PLL enabled (Clock Frequency = 4 x FOSC1)
; CONFIG OSC = ECIO6 ;EC oscillator, port function on RA6
; CONFIG OSC = EC ;EC oscillator, CLKOUT function on RA6
; CONFIG OSC = RC ;External RC oscillator, CLKO function on RA6
; CONFIG OSC = HS ;HS oscillator
; CONFIG OSC = XT ;XT oscillator
; CONFIG OSC = LP ;LP oscillator
;
; Fail-Safe Clock Monitor Enable bit
; CONFIG FCMEN = ON ;Fail-Safe Clock Monitor enabled
CONFIG FCMEN = OFF ;Fail-Safe Clock Monitor disabled
;
; Internal/External Oscillator Switchover bit
; CONFIG IESO = ON ;Oscillator Switchover mode enabled
CONFIG IESO = OFF ;Oscillator Switchover mode disabled
;
; Power-up Timer Enable bit
CONFIG PWRT = OFF ;PWRT disabled
; CONFIG PWRT = ON ;PWRT enabled
;
; Brown-out Reset Enable bits
CONFIG BOREN = SBORDIS ;Brown-out Reset enabled in hardware only (SBOREN is disabled)
; CONFIG BOREN = NOSLP ;Brown-out Reset enabled in hardware only and disabled in Sleep mode (SBOREN is disabled)
; CONFIG BOREN = ON ;Brown-out Reset enabled and controlled by software (SBOREN is enabled)
; CONFIG BOREN = OFF ;Brown-out Reset disabled in hardware and software
;
; Brown Out Reset Voltage bits
CONFIG BORV = 3 ;Minimum setting
; CONFIG BORV = 2 ;
; CONFIG BORV = 1 ;
; CONFIG BORV = 0 ;Maximum setting
;
; Watchdog Timer Enable bit
CONFIG WDT = ON ;WDT enabled
; CONFIG WDT = OFF ;WDT disabled (control is placed on the SWDTEN bit)
;
; Watchdog Timer Postscale Select bits
; CONFIG WDTPS = 32768 ;1:32768
; CONFIG WDTPS = 16384 ;1:16384
; CONFIG WDTPS = 8192 ;1:8192
; CONFIG WDTPS = 4096 ;1:4096
; CONFIG WDTPS = 2048 ;1:2048
; CONFIG WDTPS = 1024 ;1:1024
CONFIG WDTPS = 512 ;1:512
; CONFIG WDTPS = 256 ;1:256
; CONFIG WDTPS = 128 ;1:128
; CONFIG WDTPS = 64 ;1:64
; CONFIG WDTPS = 32 ;1:32
; CONFIG WDTPS = 16 ;1:16
; CONFIG WDTPS = 8 ;1:8
; CONFIG WDTPS = 4 ;1:4
; CONFIG WDTPS = 2 ;1:2
; CONFIG WDTPS = 1 ;1:1
;
; CCP2 MUX bit
CONFIG CCP2MX = PORTC ;CCP2 input/output is multiplexed with RC1
; CONFIG CCP2MX = PORTBE ;CCP2 input/output is multiplexed with RB3
;
; PORTB A/D Enable bit
; CONFIG PBADEN = ON ;PORTB&lt;4:0> pins are configured as analog input channels on Reset
CONFIG PBADEN = OFF ;PORTB&lt;4:0> pins are configured as digital I/O on Reset
;
; Low-Power Timer1 Oscillator Enable bit
; CONFIG LPT1OSC = ON ;Timer1 configured for low-power operation
CONFIG LPT1OSC = OFF ;Timer1 configured for higher power operation
;
; MCLR Pin Enable bit
CONFIG MCLRE = ON ;MCLR pin enabled; RE3 input pin disabled
; CONFIG MCLRE = OFF ;RE3 input pin enabled; MCLR disabled
;
; Stack Full/Underflow Reset Enable bit
CONFIG STVREN = ON ;Stack full/underflow will cause Reset
; CONFIG STVREN = OFF ;Stack full/underflow will not cause Reset
;
; Single-Supply ICSP Enable bit
; CONFIG LVP = ON ;Single-Supply ICSP enabled
CONFIG LVP = OFF ;Single-Supply ICSP disabled
;
; Extended Instruction Set Enable bit
; CONFIG XINST = ON ;Instruction set extension and Indexed Addressing mode enabled
CONFIG XINST = OFF ;Instruction set extension and Indexed Addressing mode disabled (Legacy mode)
;
; Background Debugger Enable bit
CONFIG DEBUG = OFF ;Background debugger disabled, RB6 and RB7 configured as general purpose I/O pins
; CONFIG DEBUG = ON ;Background debugger enabled, RB6 and RB7 are dedicated to In-Circuit Debug
;
; Code Protection bit
CONFIG CP0 = OFF ;Block 0 (000800-003FFFh) not code-protected
; CONFIG CP0 = ON ;Block 0 (000800-003FFFh) code-protected
;
; Code Protection bit
CONFIG CP1 = OFF ;Block 1 (004000-007FFFh) not code-protected
; CONFIG CP1 = ON ;Block 1 (004000-007FFFh) code-protected
;
; Code Protection bit
CONFIG CP2 = OFF ;Block 2 (008000-00BFFFh) not code-protected
; CONFIG CP2 = ON ;Block 2 (008000-00BFFFh) code-protected
;
; Code Protection bit
CONFIG CP3 = OFF ;Block 3 (00C000-00FFFFh) not code-protected
; CONFIG CP3 = ON ;Block 3 (00C000-00FFFFh) code-protected
;
; Boot Block Code Protection bit
CONFIG CPB = OFF ;Boot block (000000-0007FFh) not code-protected
; CONFIG CPB = ON ;Boot block (000000-0007FFh) code-protected
;
; Data EEPROM Code Protection bit
CONFIG CPD = OFF ;Data EEPROM not code-protected
; CONFIG CPD = ON ;Data EEPROM code-protected
;
; Write Protection bit
CONFIG WRT0 = OFF ;Block 0 (000800-003FFFh) not write-protected
; CONFIG WRT0 = ON ;Block 0 (000800-003FFFh) write-protected
;
; Write Protection bit
CONFIG WRT1 = OFF ;Block 1 (004000-007FFFh) not write-protected
; CONFIG WRT1 = ON ;Block 1 (004000-007FFFh) write-protected
;
; Write Protection bit
CONFIG WRT2 = OFF ;Block 2 (008000-00BFFFh) not write-protected
; CONFIG WRT2 = ON ;Block 2 (008000-00BFFFh) write-protected
;
; Write Protection bit
CONFIG WRT3 = OFF ;Block 3 (00C000-00FFFFh) not write-protected
; CONFIG WRT3 = ON ;Block 3 (00C000-00FFFFh) write-protected
;
; Configuration Register Write Protection bit
CONFIG WRTC = OFF ;Configuration registers (300000-3000FFh) not write-protected
; CONFIG WRTC = ON ;Configuration registers (300000-3000FFh) write-protected
;
; Boot Block Write Protection bit
CONFIG WRTB = OFF ;Boot Block (000000-0007FFh) not write-protected
; CONFIG WRTB = ON ;Boot Block (000000-0007FFh) write-protected
;
; Data EEPROM Write Protection bit
CONFIG WRTD = OFF ;Data EEPROM not write-protected
; CONFIG WRTD = ON ;Data EEPROM write-protected
;
; Table Read Protection bit
CONFIG EBTR0 = OFF ;Block 0 (000800-003FFFh) not protected from table reads executed in other blocks
; CONFIG EBTR0 = ON ;Block 0 (000800-003FFFh) protected from table reads executed in other blocks
;
; Table Read Protection bit
CONFIG EBTR1 = OFF ;Block 1 (004000-007FFFh) not protected from table reads executed in other blocks
; CONFIG EBTR1 = ON ;Block 1 (004000-007FFFh) protected from table reads executed in other blocks
;
; Table Read Protection bit
CONFIG EBTR2 = OFF ;Block 2 (008000-00BFFFh) not protected from table reads executed in other blocks
; CONFIG EBTR2 = ON ;Block 2 (008000-00BFFFh) protected from table reads executed in other blocks
;
; Table Read Protection bit
CONFIG EBTR3 = OFF ;Block 3 (00C000-00FFFFh) not protected from table reads executed in other blocks
; CONFIG EBTR3 = ON ;Block 3 (00C000-00FFFFh) protected from table reads executed in other blocks
;
; Boot Block Table Read Protection bit
CONFIG EBTRB = OFF ;Boot Block (000000-0007FFh) not protected from table reads executed in other blocks
; CONFIG EBTRB = ON ;Boot Block (000000-0007FFh) protected from table reads executed in other blocks
;
#ENDCONFIG

''''''''''''''''''''''''''''''''' end ex Richard ''''''''''''''''''''''''''''

'********************** DATA and DEFINES ***************************
DEFINE OSC 8
'Select INTIO1 (ClkOut) in the configuration menu at programming.
'Use OSCCON to select frequency & select internal oscillator block
'Use CRO to see if any ClkOut visible on Osc2/ClkOut pin 14(40) or 31(44)

Initialise:

LED1 var PORTE.1 'LATE.1 does not work either
LED2 var PORTE.2 'LATE.2 does not work either

TRISE = %00001000 'make sure PSP is OFF & MCLR active
PORTE = %00001000 '

' OSCCON = %11111110 ' 8 MHz Internal Osc Block
' ' 0------- IDLEN 0 = enters SLEEP on Sleep command = 4 uA
' ' 1------- IDLEN 1 = enters IDLE on Sleep command and draws 550 uA
' ' -111---- IRCF <2:0> Int Osc freq select 111 = 8 MHz
' ' -110---- IRCF <2:0> Int Osc freq select 110 = 4 MHz
' ' -101---- 2 MHz
' ' -100---- 1 MHz
' ' -011---- 500 kHz
' ' -010---- 250 kHz
' ' -010---- 125 kHz
' ' -000---- 31 kHz
' ' ----0--- OSTS Osc Startup Status - read only - ignore
' ' -----0-- IOFS IntOsc Freq Stable - read only - ignore
' ' ------00 System Clock Select 00 = Primary Osc
' ' ------01 Secondary (Timer1) oscillator
' ' ------1x Internal oscillator block

' WDTCON = %00000001 ' enables SWDT - needs WDT OFF in config
' ' xxxxxxx1 SWDTEN software controlled WDT enabled
ADCON0 = %00000000 ' ADC OFF
' xx0000-- CH<3:0> select analog channels
' ------0- 1 = Go, 0 = Done
' -------0 1 = ADC ON, 0 = ADC OFF
ADCON1 = %00001111 'VRef = Vdd, Vss, All ports digital
' configures all digital
' 00------ Unimplemented
' --00---- VCFG<1:0> Select Vcc & Gnd as ADC references
' ----1111 PCFG<3:0> A/D Port configuration see "register 19-1"
' ADCON2 = %00111111 'Left just (=8 bit), ADacq time = 20 Tad, ADClk = Frc
' 0------- ADFM 0 = Left Justified 8 bit mode
' -x111--- ACQ<2:0> A/D aquisition time = 20 Tad
' -----111 ADCS<2:0> A/D conversion clock select = Fr/c
CMCON = %00000111 ' Comparators OFF
' 00------ No comparator outputs
' --00---- No inversion on outputs
' ----0--- Vin to pins AN0 & AN1
' -----111 Comparators OFF
MainLoop:
High LED1 '
high led2

Pause 250 '

Low LED1 '
low led2

Pause 250 '

Goto mainloop '

ENDCODE

Any more suggestions or comments?
Thanks
BrianT

[BrianT]

Some observations. It seems the #CONFIG and #ENDCONFIG can be in column 1 but all the other values must be indented.
When I hit 'compile program' the code all compiles but when I check the CONFIG data by hitting the"C" button then all my last, hand entered, values are displayed. How can I force the new #CONFIG vales to take precedence?

BrianT

[Darrel Taylor]

In the programmer software (meProg), go to Options and make sure Update Configuration from File is checked.

[richard]

you are correct in the indenting requirements,
if you have a #config-#endconfig section in your prg then pbp3 will use your fuse settings only ,so you need to set all the fuses that can affect your project , you can't rely on any default settings . These fuse settings should be passed along to your programmer in the hex file.
you should be able to view what fuses are set in the melabs U2 USB programmer screen .

i'm not seeing an osccon=$70 in your code

I have not read the PIC18F4620 data sheet are you sure all the possible analogue functions are disabled for porte,some chips
have lpt modes which may affect porte that you may need to check for

[AvionicsMaster1]

Well, here's another thought. I don't see CONFIG3H in your configs. If I read the datasheet correctly the PBADEN needs to be set so PortB goes to all digital after a reset. I remember Darrel saying if you set any configs PBP overwrites them all and replaces them with your configs. So after a reset all the ports become analog if the PBADEN isn't set correctly. Again, if I read that f.... datasheet correctly.

I hope I quoteth the great and omnipotent one correctly. Better yet, I hope I'm right.

[AvionicsMaster1]

Sorry. For some reason I thought you were using PortB.0. After pulling my head out it looks like your LED is on PortE.0. My apologies.

[AvionicsMaster1]

I thought I'd fire up the old Proteus and see if I could duplicate the problem. Granted, this doesn't always reflect real world situations but this program and schematic will blink an LED on porte.0 and porte.1.

CLEAR

start_here:

HIGH porte.0
PAUSE 500
LOW porte.0
PAUSE 500
HIGH porte.1
PAUSE 500
LOW porte.1
PAUSE 500

GOTO start_here

END

[RayL113]

Where can I find "ALLDIGITAL.pbp"? Either download the file or get the code?
Thanks

[Demon]

http://dt.cambs.net/

Robert