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.