Pic to Pic communication

[mackrackit]

Using the below code and two PIC 16F684s I don't get the results I am looking for.

But you are getting something?
What are you using for an oscillator and how are your configs set?

[fignewt]

I am not using external OSC I assumed it used the internal OSC. I changed a few setting settings in my code and now see it is jumping to the timesup function. So it appears that the debugin is waiting but not recieving the anything and the jumps to the timesup function.

New code below:

'----------MASTER CODE------------
INCLUDE "modedefs.bas" 
DEFINE DEBUG_REG PORTC
DEFINE DEBUG_BIT 2
DEFINE DEBUG_BAUD 2400
DEFINE DEBUG_MODE 1
bvar    var     byte

Pause 2000
bvar = 1

Loop:
	DEBUG bvar
Goto Loop:


'----------SLAVE CODE------------
INCLUDE "modedefs.bas" 
DEFINE DEBUGIN_REG PORTC
DEFINE DEBUGIN_BIT 2
DEFINE DEBUG_BAUD 2400
DEFINE DEBUGIN_MODE 1

bvar   var     byte

TRISA = %001000
PORTA = %000001

Pause 2000

Loop:
	DEBUGIN 4000, timesup, [bvar]
	IF (bvar = 1) then
		PORTA = %000010
		Pause 4000
	ENDIF
Pause 2000
		PORTA = %000100
Pause 2000
		PORTA = %100000
Pause 2000

Goto Loop:

timesup:
	PORTA = %010000
Pause 2000
	PORTA = %000001
Return

[mackrackit]

Unfortunately the internal OSC may not be accurate enough for SERIAL.

You may try setting the internal to run at 4Mhz if you have not done so. I know, the data sheet says that is the default...
and add
DEFINE OSC 4
to your code. I know, another default...but why take chances?

Your best bet will be to use an external OSC.

[Archangel]

Your best bet will be to use an external OSC.

To clarify this statement, your choice of a crystal and caps, a 3 pin resonator, or an external oscillator. Or you might try a lower Baud rate with the internal to see if that works, it really depends how much and which way the intosc is off frequency. A big ALSO . . . make sure the analog stuff is turned off on those ports you are using . . . try these:

cmcon0 = 7
adcon0 = 0

PICs are funny, they default to almost everything turned on, whereas you would think it would default everything off.

[ruijc]

Hi fignewt,

a few thoughts you may try...

Since RC2 could be used as Analog, its important to set it as digital ( like Joe just told you ).
The Debug/Debugin DEFINES should place the pin output/input, but is never too much to declare it anyway.

Separate the RX from the TX and connect them to the PC and use the MicroCode Studio's serial communicator to see if each one is working before connecting them together.

I believe that it will work with the internal OSC, but you can try with an external osc and see, but...
Did not see any reference on the internal OSC speed. The default is 4Mhz, but use this:

osccon=%1100111
DEFINE OSC 4

[EarlyBird2]

A long time ago Bruce helped me with I2C comms between chips. I was having problems because it was so easy. As an example here is the slave code. I built a board with an address selector switch connected to port C so that I could place them on a Bus without having to reprogram them. The Slaves are monitoring inputs from Volt Free Contacts conected to Port B.

' PicBasic Pro I2C slave program - PIC16F72/PIC-X1
    ' bootloader and OSC settings
'DEFINE LOADER_USED 1 ' bootloader
DEFINE osc 20
INCLUDE "modedefs.bas"

' Alias pins
scl     VAR     PORTC.3         ' I2C clock input
sda     VAR     PORTC.4         ' I2C data input


' Define used register flags
SSPIF   VAR     PIR1.3          ' SSP (I2C) interrupt flag
BF      VAR     SSPSTAT.0       ' SSP (I2C) Buffer Full
R_W     VAR     SSPSTAT.2       ' SSP (I2C) Read/Write
D_A     VAR     SSPSTAT.5       ' SSP (I2C) Data/Address
CKP     VAR     SSPCON.4        ' SSP (I2C) SCK Release Control
SSPEN   VAR     SSPCON.5        ' SSP (I2C) Enable
SSPOV   VAR     SSPCON.6        ' SSP (I2C) Receive Overflow Indicator
WCOL    VAR     SSPCON.7        ' SSP (I2C) Write Collision Detect



' Allocate RAM
result	VAR		BYTE			' ADC result
datain 	VAR     BYTE			' Data in 
readcnt	VAR     BYTE            ' I2C read count
I2Caddress	VAR		BYTE			' Our address	


' Initialize ports and directions
        TRISA = %11111111
		TRISB = %11111111
		TRISC = %11111111
' Initialize I2C slave mode reading inputs from hardware address settings
        I2Caddress=0
        IF PORTC.0=0 Then I2Caddress=I2Caddress+1
        IF PORTC.1=0 Then I2Caddress=I2Caddress+2
        IF PORTC.2=0 Then I2Caddress=I2Caddress+4
        IF PORTC.5=0 Then I2Caddress=I2Caddress+8
        
        
        SSPADD = I2Caddress		' Set our address
        SSPCON = $36			' Set to I2C slave with 7-bit address
        

While 1>0
      
        While NOT SSPIF
        Wend			' Check for I2C interrupt flag

		SSPIF = 0				' Clear interrupt flag
        IF D_A = 0 Then
        readcnt = 0		' Mark as first read
        EndIF
      
	
        SSPBUF = PORTB	' Get data from array
        CKP = 1                 	' Release SCL line
        readcnt = readcnt + 1   	' Move along read count
 Wend

Steve