PIC16F62X outputs

All,

Im programming a PIC16F628 pic.
I have a problem where I need a lot of outputs and I don’t know how to stop some ports from performing there alternate function.

Ports in question are
RA4
RB6
RB7

Although I am specifying

CMCON = 7 ' PortA = digital I/O
VRCON = 0 ' A/D Voltage reference disabled
TRISA=%00000000 ' Or TRISA = 0 sets all the PORTA pins to outputs
TRISB=%01000000

They are still randomly setting the pins to be there other function.

Anyone know the command or how I can just make them OUTPUT pins.

Thanks

What about the whole code?

this is very roufe. Im still debugging and playing.


'
' PIC Defines
' -----------
@ DEVICE pic16F628, INTRC_OSC_NOCLKOUT ' System Clock Options Saves A6, A7
@ DEVICE pic16F628, WDT_ON ' Watchdog Timer
@ DEVICE pic16F628, PWRT_ON ' Power-On Timer
@ DEVICE pic16F628, MCLR_OFF ' Master Clear Options (Internal) Saves A5
@ DEVICE pic16F628, BOD_ON ' Brown-Out Detect
@ DEVICE pic16F628, LVP_OFF ' Low-Voltage Programming
@ DEVICE pic16F628, CPD_OFF ' Data Memory Code Protect
@ DEVICE pic16F628, PROTECT_OFF ' Program Code Protection

VRCON = 0 ' A/D Voltage reference disabled
CMCON = 7 ' disable analog comparators on almost any PIC so equipped


TRISA=%00000000 ' Or TRISA = 0 sets all the PORTA pins to outputs
TRISB=%01000000

Include "modedefs.bas" ' Include serial modes

' Ports
pLcd_dat var PORTA ' LCD 8 bit data bus
pRS Var PORTB.0 ' RS
pE VAR PORTB.4 ' E
pCs1 VAR PORTB.7 ' Cable Select 1
pLed Var PORTB.3 ' Status LED

GoTo init '****** jump past the routines below ******



send:

pCs1 = 0 ' TODO Change
'pause 1
pRS = gRS
pause 2
'pause 42
pLcd_dat = glcd_dat
PORTB.6 = glcd_dat.4
PORTB.5 = glcd_dat.5

'pause 1
pE = 1
'pauseUS 10
'pause 100

pause 2
'pause 60

pE = 0
'pause 1
pRS = 0
pCs1 = 1
'pCs2 = 1
'pCs3 = 1
pause 7
'pause 140
Return




init: 'Initialization


' H
for i=0 to 4
LOOKUP2 i,[$7F,$08,$08,$08,$7F],glcd_dat
GoSub send
Next

goto init

mmm what about if you use HIGH/LOW instead of Myvar=0, Myvar=1???

Don't forget port A.5 is always an input port. It is not possible to get it as an output port even if you say trisa = %00000000

>> Ports in question are
>> RA4
>> RB6
>> RB7

---
RA4 is multiplexed with T0CKI and CMP2. You've already taken care of CMP2 with the CMCON = 7. The T0CKI input is controlled by the T0CS bit in the OPTION_REG which defaults to 1 (Timer0 input is T0CKI). You can turn this off by setting OPTION_REG.5 = 0. However This will not affect the operation of RA4 as an output, which appears to be the problem.

RA4 is an open collector type output. It requires a Pull-Up resistor on the output to be used as a normal digital output.

---
RB6 is multiplexed with T1OSO, T1CKI and PGC. T1OSO and T1CKI are controlled by T1CON bits 1 (TMR1CS) and 3 (T1OSCEN). Both of these bits default to 0, which means that the multiplexed functions are disabled. PGC is only used during programming, but if you leave a programmer connected during operation, you may have problems.

However, in your program you have ...

TRISB=%01000000

With a 1 in the bit 6 position, RB6 is set to INPUT. As we found out in your other thread, you want RB6 to be an output.

---
RB7 is multiplexed with T1OSO and PGD. Again, T1OSO is disabled by default (T1OSCEN). and the previous mention of the programmer applies here too.

It may be that you grabbed an old file for this post. But the correction from the "other" thread is incorrect in this listing.

pLcd_dat = glcd_dat
PORTB.6 = glcd_dat.4
PORTB.5 = glcd_dat.5

change to

pLcd_dat = glcd_dat
PORTB.6 = glcd_dat.6
PORTB.5 = glcd_dat.7

---
Also, like mat says, RA5 is input only, so it will have to be moved to a different pin.

HTH,
   Darrel

thanks so much for your help.

I found a sample that had a pull up on A5. This i tested and it fixed the problem.

The TRISB=%01000000 was a mistake on my part. I thought it was %01234567 and i your saying that it should be 76543210
I need B1 as a input so i chnaged to TRISB=%00000010

Oviously i have much to learn.