Serial and interrupt

[test153]

How do one use a interrupt with the SERIN function? Basically what I'm trying to accomplish is to have a blinking LED and an interrupt on porta.5 - where I retrive a byte and then continue with the main loop.

Currently my code isn't working as expected. It seems that the interrupt doesn't resume the main program loop after SERIN.

I'm compiling for pic12f629.

btw, to be able to do multitasking (updating LEDS and receiving from serial port) do I need to use interrupts?

INCLUDE "modedefs.bas" 'For the Baud Rate modes

char var byte

ON INTERRUPT GOTO myint ' Interrupt handler is myint

INTCON.3 = 1 'PORTA change interupt enabled
INTCON.7 = 1 'Global interrupt enabled
IOC.3 = 1

led_on:
high porta.0
pause 500
low porta.0
pause 500
goto led_on

' Interrupt handler 
DISABLE ' Disable interrupts in handler
myint: 
SerIN PORTA.3, T9600, ["b"],char    ' Will be uesed later
INTCON.0 = 0 'Clear GPIF
RESUME ' Return to main program
ENABLE ' Enable interrupts after handler

End

[mister_e]

You just don't want to use a Software bit banged solution with interrupt. Move on a PIC with Real Hardware USART and use USART inetrrupt.

It might be doable with your PIC, but on slower baudrate, using ASM interrupt (maybe instant interrupt), and an home made serial routine. No way this might work 100% properly with ON INTERRUPT even more with internal OSC.

You could still try something and reduce your delay, using short PAUSEUS loop might work better.

Using DEBUGIN would also help.

If you build yourself the Master you could send few garbarge data, then a Synch character, then your data. Says
SEROUT2 ....[REP 0\32, "~", YourData]

on the receiver side you just use WAIT("~") ... might work.....

[test153]

The thing is that it's kinda to late to change the pic for my current project

Well it seems that I will be coding my own serial routine after all...

In what way is the debugIN function different except the syntax?

Do you have some more info about instant interrupt? Something to get me started.

Anyway thanks for the help

[mister_e]

DEBUGIN works better on higher baudrate on Slower Speed OSC. Check your manual about that. Syntax is a bit different as well.

Instant-Interrupt
http://darreltaylor.com/DT_INTS-14/intro.html

[test153]

Before posting posting to this forum I tried "DT_INTS-14" but I got some compailing errors, any idea how to fix them?

wsave3 position request 416 beyond RAM_END 95
wsave2 position request 288 beyond RAM_END 95
wsave1 position request 160 beyond RAM_END 95
Unable to fit variable RS2_Save

[mister_e]

open DT_INTS-14.bas file, there you'll find

' --- IF any of these three lines cause an error ?? ---------------------------- 
'       Comment them out to fix the problem ----
' -- It depends on which Chip you are using, as to which variables are needed --
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

So, just modify it as requested

' --- IF any of these three lines cause an error ?? ---------------------------- 
'       Comment them out to fix the problem ----
' -- It depends on which Chip you are using, as to which variables are needed --
;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