Serout problem

[Agent36]

Hi,

I am having a couple of problems with the above code. I changed it so that I could run it on two 16f628 chips, this works with out any problems.
Happy that I could tx and rx I wanted to tx using a 12f675 chip and rx on a 16f628.

Changing the tx code for a 12f675 and compiling it gave no errors. The leds flash ok and when I put an led on the serout pin I see the data. When I tx the code to the rx 16f628 via a tx the rx wont respond. I then hardwired the 12f675 to the 16f628 removing the tx/rx, it still wont work.
Can someone please check my code or suggest why it wont work.
Here is the code;

@ DEVICE PIC12F675, INTRC_OSC_NOCLKOUT
' System Clock Options (Internal)
@ DEVICE PIC12F675, WDT_ON
' Watchdog Timer
@ DEVICE PIC12F675, PWRT_ON
' Power-On Timer
@ DEVICE PIC12F675, MCLR_OFF
' Master Clear Options (Internal)
@ DEVICE PIC12F675, BOD_OFF
' Brown-Out Detect
@ DEVICE PIC12F675, CPD_OFF
' Data Memory Code Protect
@ DEVICE PIC12F675, PROTECT_ON

'PICBASIC PROGRAM

ANSEL = 0
CMCON = 7
TRISIO =%001000


INCLUDE "modedefs.bas"


txout VAR GPIO.4 : Output txout : dataout VAR BYTE
ledcount VAR BYTE
led1 VAR GPIO.0 : Output led1 : led2 VAR GPIO.1 : Output led2
led3 VAR GPIO.2 : Output led3 : led4 VAR GPIO.5 : Output led4
key VAR GPIO.3 : Input key 'push button on gpio.3
'1K-10K resistor from portb.0 to ground (pulldown)
'push button is wired between portb.0 and +5v
'initial LED check
led1 = 1 : Pause 500 : led1 = 0 : led2 = 1 : Pause 500 : led2 = 0
led3 = 1 : Pause 500 : led3 = 0 : led4 = 1 : Pause 500 : led4 = 0

mainloop:

IF key = 0 Then 'button not pressed
GoTo mainloop
EndIF
IF key = 1 Then
Pause 50 'wait 50ms for switch to debounce then check again
IF key = 1 Then 'if it's still pressed, then increment the count
ledcount = ledcount + 1
dataout = $55 '($55 = manchester encoded $0)
'train the receiver by sending 5 each of the $55's, may need more
'just copy the line below to make it send out more characters
SerOut txout, n2400, [ dataout, dataout, dataout, dataout, dataout ]
EndIF
EndIF

IF ledcount = 0 Then 'all leds off
dataout = $66 'manchester encoded $5, use because $0 is reserved
SerOut txout, n2400, [ dataout ]
'may have to send data more than once depending on how well the receiver
'can capture the data. Shouldn't have a problem sending it once
led1 = 0 : led2 = 0 : led3 = 0 : led4 = 0
EndIF

IF ledcount = 1 Then '1st led on
dataout = $56 'manchester encoded $1
SerOut txout, n2400, [ dataout ]
led1 = 1 : led2 = 0 : led3 = 0 : led4 = 0
EndIF

IF ledcount = 2 Then '2nd led on and so on and so on down the line....
dataout = $59 'manchester encoded $2
SerOut txout, n2400, [ dataout ]
led1 = 0 : led2 = 1 : led3 = 0 : led4 = 0
EndIF

IF ledcount = 3 Then
dataout = $5a 'manchester encoded $3
SerOut txout, n2400, [ dataout ]
led1 = 0 : led2 = 0 : led3 = 1 : led4 = 0
EndIF

IF ledcount = 4 Then
dataout = $65 'manchester encoded $4
SerOut txout, n2400, [ dataout ]
led1 = 0 : led2 = 0 : led3 = 0 : led4 = 1
EndIF

IF ledcount = 5 Then 'reset led count, roll it back to 0
ledcount = 0 'and turn leds off since count is back to 0
dataout = $66 'manchester encoded $5 (same thing as ledcount = 0 above)
SerOut txout, n2400, [ dataout ]
led1 = 0 : led2 = 0 : led3 = 0 : led4 = 0
EndIF

GoTo mainloop

End

I am using the two 16f628's with internal clock selected with no problem

thanks Nick

[skimask]

The internal clock on the 12F675 is probably too far off (i.e. 12F675 transmitting at 2350 baud, 16F628 receiving at 2400 baud, something like that).
Try slowing down the baud rate or moving the OSCCAL value on the 12F675 around a bit and see what happens.

[mister_e]

If the calibration data is still intact, you try to add

DEFINE OSCCAL_1K 1

Before ANSEL=0

[Agent36]

Hi,
thanks for the replys, I thought it might be something to do with the internal osc. Tried the program code on a 16f819 worked fine.
So i got a brand new 12f675, checked the osc cal and band gap values, loaded the code and rechecked them. I did this because I have had other timing issues with these 12f675's. Some of which were down to me I think.
I like to stick with an 8 pin chip because I aim to fit the board into a keyfob, so space is tight.
First I will try the soloutions you have offered.

Thanks for your time.

Nick

[Agent36]

Hi,

Thanks for the info regarding the DEFINE OSCCAL_1K 1
Adding that to the program code has solved my little problem.

I have found referances about this define in the pbp manual, for some reason I thought that DEFINE OSC 4mhz was correct.

I assume that DEFINE OSCCAL_1K 1 means

org 0
movwf OSCCAL

Thanks for your time........Nick