PIC puzzle

[randy.day]

Okay, new PIC issue causing premature forcible hair removal. The code below
is supposed to put 1's on the PORTB pins (PIC16F690). It's not happening;
what am I missing?

BANKSEL 0x01
clrf TRISB ; PORTB all output
clrf TRISC ; PORTC all output
BANKSEL 0x00
bcf SSPCON, 5
movlw 0xFF
movwf PORTB
goto $

 

[Richard Seriani]

Okay, new PIC issue causing premature forcible hair removal. The code
below
is supposed to put 1's on the PORTB pins (PIC16F690). It's not happening;
what am I missing?

BANKSEL 0x01
clrf TRISB ; PORTB all output
clrf TRISC ; PORTC all output
BANKSEL 0x00
bcf SSPCON, 5
movlw 0xFF
movwf PORTB
goto $

Randy,

From the MPASM Help file: This directive is an instruction to the assembler
and linker to generate bank selecting code to set the bank to the bank
containing the designated label.

So, unless 0x01 is a label that somehow defines TRISB, it looks like you are
never setting PORTB or PORTC as outputs. You may want to try setting the
individual STATUS register bits to perform bank selection (see Example 4-3
in the datasheet). If not, use a valid label for banksel (for example,
TRISB, or any other Bank1 register). Same for coming back to Bank0. Check
out the examples in the MPASM help file.

You only provided a snippet of code, but you may also want to look at
whether your ports default to analog or digital on startup.

I hope this helps.

Richard

 

[Mike Wahler]

Okay, new PIC issue causing premature forcible hair removal. The code
below
is supposed to put 1's on the PORTB pins (PIC16F690). It's not happening;
what am I missing?

BANKSEL 0x01
clrf TRISB ; PORTB all output
clrf TRISC ; PORTC all output
BANKSEL 0x00
bcf SSPCON, 5
movlw 0xFF
movwf PORTB
goto $

banksel TRISB
clrf TRISB
movlw 0xFF
banksel PORTB
movwf PORTB

See your Microchip documentation for how to use
'banksel' properly.

-Mike