Replacing existing pic

[Freman]

I'm not actually using the serial at the moment, I'm just trying to get to the "other" part of the code, but I'll try 2400 bps, I'll also try the osccal

So you're telling me I should set that bit to 0 in my code?


Nope still no go This is the code and attached is the schematic

I know the slave is bringing the pins high (multi-meter and beep confirms it)

Edit: One clue I have is.... if I comment out the serial routine and tell it to goto the 'testSlave' label, it works fine

' Configure the pic
@     device pic12F675, INTRC_OSC_NOCLKOUT, WDT_ON, PWRT_ON, MCLR_OFF, BOD_ON, CPD_OFF, PROTECT_OFF

DEFINE OSCCAL_1K 1
N2400   con      4

CMCON        = 7
ANSEL        = 0
OPTION_REG.7 = 0

Relay1       VAR GPIO.5
Relay2       VAR GPIO.4

SlavePower   VAR GPIO.2
SlaveRelay1  VAR GPIO.0
SlaveRelay2  VAR GPIO.1

Serial       VAR GPIO.3

B0           var BYTE
SlaveState   VAR BYTE
WhichRelay   VAR BYTE

INPUT SlaveRelay1
INPUT SlaveRelay2
INPUT Serial

OUTPUT Relay1
OUTPUT Relay2
OUTPUT SlavePower

LOW Relay1
LOW Relay2

restart:
SlaveState = 0
PAUSEUS 1000
HIGH SlavePower

main:
    B0 = 0
    SERIN Serial, N2400, 20, testSlave, [1], B0
    LOW SlavePower
    SELECT CASE B0
        CASE 2
            GOSUB subUp
        CASE 3
            GOSUB subDown
        CASE 4
            GOSUB subStop
    END SELECT
    GOTO restart

testSlave:    
    WhichRelay = GPIO & 3
    IF SlaveState <> WhichRelay THEN
        SlaveState = WhichRelay
        SELECT CASE WhichRelay
            CASE 0
                GOSUB subStop
            CASE 1
                GOSUB SubUp
            Case 2
                GOSUB subDown
        END SELECT
    ENDIF   
goto main

subUp:
    LOW Relay2
    HIGH Relay1
    RETURN 
subDown:
    LOW RELAY1
    HIGH Relay2
    RETURN
subStop:
    LOW Relay1
    LOW Relay2
    RETURN

[Freman]

SOLVED

I think

Throw a 10k resistor from the serial pin to ground. The question now is, should that resistor remain even after I actually hook up the serial signal from the other device?

[PC - USB > serial] ---> [Main Board (PCCLD)] ---> {1 way serial} ---> [New/Master PIC]

Should that resistor remain, or can I turf it once I hook up the serial?

[mister_e]

As you're using the Timeout, the serial pin must Idle at the right level. Not a bad idea to leave this resistor.

http://www.picbasic.co.uk/forum/show...86&postcount=5

[Freman]

Well, all in all it works - most of the time.... well half of the time

The PCCLD pic is a PIC16F628A running at 20 Mhz
The Master pic is a PIC16F675 running on internal clock at 4Mhz

I'm pretty sure my programmer has fried the CALIB so DEFINE OSCCAL_1K 1 breaks the serial function.

The ONLY baud of those I've tried (1200, 2400 and 9600) that works (somewhat randomly) is 9600 - none of the others work.

Not sure if that's more a function of the PCCLD pic or the Master pic

[Freman]

I'm about ready to give up on serial ports

It shouldn't work at 9600 yet it does randomly...

It should work at 2400 but it doesn't at all

[mister_e]

IF the DEFINE OSCCAL break the serial comm and almost everything, it's a good sign your device programmer screwed the internal calibration, that's for sure. If you have a PICKIT2, you can recover it in few seconds with the OSCCAL Auto regenerate utility.

Acetronics also posted something here.

Lost your OSCCAL Value ???
http://www.picbasic.co.uk/forum/showthread.php?t=7588&

One thing is sure, you're using a BitBanging Serial communication, you may miss some bytes here and there. Using a Hardware USART provide a 2 bytes buffer and Interrupt capability... which are handy.

For a simple test, remove the relay check and keep only the serial part, without timeout. See if it works better.

[Freman]

Given up, moving up to the pic16f628a - Means I can do more as well.
Another consideration I had was using maxim one wire components to free up 4 of the pins, I could have put a crystal on it then.

Still can't really use the hardware uart on the pic16f628a because the pic it's talking to is already using it's hardware uart.

I'll keep a note on that recovery source, that will come in useful

But here's my new schematic - http://users.on.net/freman/images/el...ceiverplus.png

I used the interrupt pin for serial communication, so I could interrupt by sending it high, then send bytes
The other option is to use the hardware uart but it'd be connected to software serial at the other end...

I'm not set on that yet, this one's still on the breadboard.