RS232 interrupt problems

[jchait]

Can anybody see what is wrong with this program?
It should toggle the RB1 every 1msec or so.
If I assign port D pins as inputs, it works fine, but if I assigned as outputs, it does not.
I’m using version 3.179

Any ideas?

Thanks

Jaime

///////////////////////////////////////////////////////////////////////////
#include <18F452.H>

#device *=16
#device ADC=10
#fuses H4, NOWDT, NOPROTECT, PUT , NOLVP

#use delay(clock=40000000)
#use rs232(baud=9600,xmit=PIN_C6,rcv=PIN_C7)

#bit TST_PT = 0xF81.1

char RX_buffer[256];
int endbuf, startbuf;

#int_rda
void serial_isr() {
TST_PT = !TST_PT;
RX_buffer[endbuf++]=getc();
endbuf &= 0xFF;
}

void main(void)
{
set_tris_b(0x00); // All outputs
set_tris_c(0xBF); // All inputs except TX (RC6)

set_tris_d(0xFF); // Port D as input (WORKS)
// set_tris_d(0x00); // Port D as output (DOES NOT WORK)

endbuf = 0; // SETUP RX_RS232
startbuf = 0;

enable_interrupts(int_rda);
enable_interrupts(global);
while (1) {
}

}

[Haplo]

Just a quick note: The binary NOT operator in C is ~ not !. Also, you can use the function output_toggle(). Try the following lines and see if it makes a difference:

TST_PT = ~TST_PT;

And

output_toggle(PIN_D1);

[PCM programmer]

[jchait]

Thanks Haplo, but using “~” nor out_toggle() helped. (It is a good practice to start using the right operator though).

To PCM programmer.
1) Yes, I send a long file (300K) via RS232 using a terminal program (Tera-term and the Send function). So I can see the 500 Hz square wave as long as the file is being transferred.
2) Nothing is connected to port D
3) Good idea
4) Good idea.

I did replace the 452 by a 458 and things started working the way it supposed to.
I compared the LST files and they do not match 100% but very close (I’m including these parts bellow). So I don’t know if there was something wrong with that particular 452 or ?????

Any ways.

Thanks for your input.

Jaime



PIC18F452
.................... void main(void)
.................... {
00BE: NOP(FFFF)
00C0: CLRF FF8
00C2: BCF FD0.7
00C4: BSF 0D.7
00C6: CLRF FEA
00C8: CLRF FE9
00CA: MOVLW 06
00CC: MOVWF FC1
00CE: MOVLW 40
00D0: MOVWF FAF
00D2: MOVLW 22
00D4: MOVWF FAC
00D6: MOVLW 90
00D8: MOVWF FAB
.................... set_tris_b(0x00); // All outputs
00DA: MOVLW 00
00DC: MOVWF F93
.................... set_tris_c(0xBF); // All inputs except TX (RC6)
00DE: MOVLW BF
00E0: MOVWF F94
....................
.................... // set_tris_d(0xFF); // Port D as input (OK)
.................... set_tris_d(0x00); // Port D as output (not OK)
00E2: MOVLW 00
00E4: MOVWF F95
....................
.................... endbuf = 0; // SETUP RX_RS232
00E6: MOVLB 1
00E8: CLRF x17
.................... startbuf = 0;
00EA: CLRF x18
....................
.................... enable_interrupts(int_rda);
00EC: BSF F9D.5
.................... enable_interrupts(global);
00EE: MOVLW C0
00F0: IORWF FF2,F
.................... while (1) {
.................... }
00F2: GOTO 00F2
....................
.................... }
....................
00F6: SLEEP

Configuration Fuses:
Word 1: 2600 H4 NOOSCSEN
Word 2: 0E0E BROWNOUT WDT128 NOWDT BORV20 PUT
Word 3: 0100 CCP2C1
Word 4: 0081 STVREN NODEBUG NOLVP
Word 5: C00F NOPROTECT NOCPD NOCPB
Word 6: E00F NOWRT NOWRTD NOWRTB NOWRTC
Word 7: 400F NOEBTR NOEBTRB


PIC18F458
.................... void main(void)
.................... {
00BE: NOP(FFFF)
00C0: CLRF FF8
00C2: BCF FD0.7
00C4: BSF 0D.7
00C6: CLRF FEA
00C8: CLRF FE9
00CA: MOVLW 06
00CC: MOVWF FC1
00CE: MOVLW 07
00D0: MOVWF FB4
00D2: MOVLW 40
00D4: MOVWF FAF
00D6: MOVLW 22
00D8: MOVWF FAC
00DA: MOVLW 90
00DC: MOVWF FAB
.................... set_tris_b(0x00); // All outputs
00DE: MOVLW 00
00E0: MOVWF F93
.................... set_tris_c(0xBF); // All inputs except TX (RC6)
00E2: MOVLW BF
00E4: MOVWF F94
....................
.................... // set_tris_d(0xFF); // Port D as input (OK)
.................... set_tris_d(0x00); // Port D as output (not OK)
00E6: MOVLW 00
00E8: MOVWF F95
....................
.................... endbuf = 0; // SETUP RX_RS232
00EA: MOVLB 1
00EC: CLRF x17
.................... startbuf = 0;
00EE: CLRF x18
....................
.................... enable_interrupts(int_rda);
00F0: BSF F9D.5
.................... enable_interrupts(global);
00F2: MOVLW C0
00F4: IORWF FF2,F
.................... while (1) {
.................... }
00F6: GOTO 00F6
....................
.................... }
....................
00FA: SLEEP

Configuration Fuses:
Word 1: 2600 H4 NOOSCSEN
Word 2: 0E0E BROWNOUT WDT128 NOWDT BORV20 PUT
Word 3: 0000
Word 4: 0081 STVREN NODEBUG NOLVP
Word 5: C00F NOPROTECT NOCPD NOCPB
Word 6: E00F NOWRT NOWRTD NOWRTB NOWRTC
Word 7: 400F NOEBTR NOEB