gnupic: PIC18F47J53
Subject:
PIC18F47J53
From:
Luis de Arquer ####@####.####
Date:
12 Aug 2013 16:59:22 -0000
Message-Id: <CAD_DGvm7mpREfkaLqCfDQev1xh_4pqXxoCguyKoQ-i+e+bfWng@mail.gmail.com>
Gents,
I am using sdcc + gputils on a home-made board, with a PIC18F47J53
(44-pin TQFP microcontroller, and I am coming accross a few issues.
The fact that there are more than one issue, makes me think that maybe
something electrical is wrong.
However, just in case someone has experienced this before, I am
posting the most obvious of the problems.
I have tried a simple program blinking an LED. It does work, if I use
the instructions
PORTB &= 0x08
PORTB |= 0x08
for toggling the LED (see asm translation below).
However if I use
PORTB ^= 0x08
which translates to a BTG (bit toggle) instruction, it won't blink at
all -it will light the LED up though, but no blinking can be seen even
with the oscilloscope.
It looks to me that the C -> asm compilation is OK.
I know it sounds a bit ridiculous, and I think the chances are 50/50
that I am either making a very obvious error on the software side, or
there is some electronic issue on the board. However, after hours
messing around I couldn't find an explanation. Maybe the BTG
instruction is not available in the j-series, or coded in a different
way?
Below is the and/or-version asm code (the one that works), the
BTG-version asm code, and the gpasm/gplink command line.
BTW, has anyone succesfully used this microcontroller with gputils before?
Regards,
Luis de Arquer
********************* AND/OR version (works OK!)
******************************
; I code from now on!
; ; Starting pCode block
S_test__main code
_main:
; .line 26; test.c TRISB = ~0x08;
MOVLW 0xf7
MOVWF _TRISB
; .line 27; test.c PORTB = PORTB | 0x08;
BSF _PORTB, 3
_00132_DS_:
; .line 31; test.c sleep_a_while(0x20);
MOVLW 0x20
MOVWF POSTDEC1
CALL _sleep_a_while
MOVF POSTINC1, F
; .line 33; test.c PORTB &= ~0x08;
MOVF _PORTB, W
MOVWF r0x00
MOVLW 0xf7
ANDWF r0x00, W
MOVWF _PORTB
; .line 35; test.c sleep_a_while(0x20);
MOVLW 0x20
MOVWF POSTDEC1
CALL _sleep_a_while
MOVF POSTINC1, F
; .line 37; test.c PORTB |= 0x08;
BSF _PORTB, 3
BRA _00132_DS_
RETURN
********************* BTG version -not working :( ************************
; I code from now on!
; ; Starting pCode block
S_test__main code
_main:
; .line 26; test.c TRISB = ~0x08;
MOVLW 0xf7
MOVWF _TRISB
; .line 27; test.c PORTB = PORTB | 0x08;
BSF _PORTB, 3
_00132_DS_:
; .line 31; test.c sleep_a_while(0x20);
MOVLW 0x20
MOVWF POSTDEC1
CALL _sleep_a_while
MOVF POSTINC1, F
; .line 33; test.c PORTB ^= 0x08;
BTG _PORTB, 3
; .line 35; test.c sleep_a_while(0x20);
MOVLW 0x20
MOVWF POSTDEC1
CALL _sleep_a_while
MOVF POSTINC1, F
; .line 37; test.c PORTB ^= 0x08;
BTG _PORTB, 3
BRA _00132_DS_
RETURN
********************* Command line ******************************
+ /usr/local/bin/gpasm -DSTACK_MODEL_SMALL -D__STACK_MODEL_SMALL -o
test.o -c test.asm
+ /usr/local/bin/gplink -I/usr/local/bin/../share/sdcc/lib/pic16
-I/usr/local/share/sdcc/lib/pic16
-I/usr/local/bin/../share/sdcc/non-free/lib/pic16
-I/usr/local/share/sdcc/non-free/lib/pic16 -w -r -o test test.o
crt0.o libdev18f47j53.lib libsdcc.lib libc18f.lib
message: using default linker script
"/usr/local/share/gputils/lkr/18f47j53_g.lkr"
