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freesat
Joined: 08 Feb 2011
Posts: 32
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| help! 16 bit array index not working |
 Posted: Thu Nov 24, 2011 7:41 pm |
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Hi guys,
I'm try to use array with 16 bit index but no success, when using 8 bit index its ok!
| Code: |
#include <18F4550.h>
#use delay(clock=20M)
#build( reset=0x1000, interrupt=0x1008 )
#org 0x0000,0x0FFF {}
int8 test_array[512];
void main() {
test_array[2] = 0x30;
test_array[500] = 0x30;
while ( 1) {
/* Works! */
if ( test_array[2] == 0x30 ) { output_toggle( PIN_B2 ); }
/* not working! pic just freeze! */
if ( test_array[500] == 0x30 ) { output_toggle( PIN_B2 ); }
delay_ms( 500 );
}
}
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Using compiler 4.124
The code is only for view! do not try to build.
My concept is not correct? or there is a problem with compiler ?
My real code is using usb_cdc & microchip bootloader! pic can start and works, except when use array index > 255.
| Code: |
CCS PCH C Compiler, Version 4.124, 5967 24-nov-11 23:35
Filename: D:\pic\test_array.lst
ROM used: 116 bytes (0%)
Largest free fragment is 28552
RAM used: 505 (25%) at main() level
506 (25%) worst case
Stack: 1 locations
*
1000: GOTO 1032
.................... #include <18F4550.h>
.................... //////// Standard Header file for the PIC18F4550 device ////////////////
.................... #device PIC18F4550
.................... #list
....................
.................... #use delay(clock=20M)
*
1008: MOVLW 02
100A: MOVWF FEA
100C: MOVLW 05
100E: MOVWF FE9
1010: MOVF FEF,W
1012: BZ 102E
1014: MOVLW 06
1016: MOVWF 01
1018: CLRF 00
101A: DECFSZ 00,F
101C: BRA 101A
101E: DECFSZ 01,F
1020: BRA 1018
1022: MOVLW 7B
1024: MOVWF 00
1026: DECFSZ 00,F
1028: BRA 1026
102A: DECFSZ FEF,F
102C: BRA 1014
102E: GOTO 1070 (RETURN)
....................
.................... #build( reset=0x1000, interrupt=0x1008 )
.................... #org 0x0000,0x0FFF {}
....................
.................... int8 test_array[512];
....................
.................... void main() {
1032: CLRF FF8
1034: BCF FD0.7
1036: CLRF FEA
1038: CLRF FE9
103A: MOVF FC1,W
103C: ANDLW C0
103E: IORLW 0F
1040: MOVWF FC1
1042: MOVLW 07
1044: MOVWF FB4
.................... test_array[2] = 0x30;
1046: MOVLW 30
1048: MOVWF 06
.................... test_array[500] = 0x30;
104A: MOVLB 1
104C: MOVWF xF8
....................
.................... while ( 1) {
.................... /* Works! */
.................... if ( test_array[2] == 0x30 ) { output_toggle( PIN_B2 ); }
104E: MOVF 06,W
1050: SUBLW 30
1052: BNZ 1058
1054: BCF F93.2
1056: BTG F8A.2
....................
.................... /* not working! pic just freeze! */
.................... if ( test_array[500] == 0x30 ) { output_toggle( PIN_B2 ); }
1058: MOVF xF8,W
105A: SUBLW 30
105C: BNZ 1062
105E: BCF F93.2
1060: BTG F8A.2
....................
.................... delay_ms( 500 );
1062: MOVLW 02
1064: MOVLB 2
1066: MOVWF x04
1068: MOVLW FA
106A: MOVWF x05
106C: MOVLB 0
106E: BRA 1008
1070: MOVLB 2
1072: DECFSZ x04,F
1074: BRA 1068
.................... }
1076: MOVLB 1
1078: BRA 104E
.................... }
107A: SLEEP
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Thanks.
edited to correct from 500 to 512 array size.
Last edited by freesat on Thu Nov 24, 2011 8:01 pm; edited 1 time in total |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Thu Nov 24, 2011 7:48 pm |
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| Quote: | int8 test_array[500];
void main() {
test_array[2] = 0x30;
test_array[500] = 0x30;
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This is a mistake. See this FAQ on common errors in C.
See section 2.4 on size of arrays.
http://www.drpaulcarter.com/cs/common-c-errors.php |
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freesat
Joined: 08 Feb 2011
Posts: 32
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| Posted: Thu Nov 24, 2011 7:59 pm |
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Im Sorry PCM!
the correct is...
| Code: |
int8 test_array[512];
void main() {
test_array[2] = 0x30;
test_array[500] = 0x30;
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i know array start at zero.
i will correct on original post. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Thu Nov 24, 2011 8:07 pm |
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I modified your test program so it would be better for MPLAB simulator.
I can't test with 4.124 at the moment, so I tested it with vs. 4.119.
It works:
| Quote: |
test_array[2] value: 0x30
test_array[500] value: 0x30
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I can test it with 4.124 later today or tomorrow, but I suspect that it will
still work.
| Code: |
#include <18F4550.h>
#fuses HS, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP
#use delay(clock=20M)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
#build( reset=0x1000, interrupt=0x1008 )
#org 0x0000,0x0FFF {}
int8 test_array[512];
void main()
{
test_array[2] = 0x30;
test_array[500] = 0x30;
if(test_array[2] == 0x30 )
printf("test_array[2] value: 0x30 \r");
if(test_array[500] == 0x30 )
printf("test_array[500] value: 0x30 \r");
while(1);
} |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19516
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| Posted: Fri Nov 25, 2011 4:30 am |
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Some comments:
The assembler posted works fine.
It just loads 0x30, into location 6, and also into location 0x1F8. These are the values it then tests.
Have you actually tested the code 'as posted', or is this cut out of something else?. If the latter, my guess would be that you have some other problem. Classic things would be:
1) Something walking over part of memory.
2) Using a 16bit array index, with a index value that is updated in an interrupt - remember if you do this, you _must_ disable interrupts round the point where you use the value, or provide some equivalent method of ensuring that the value doesn't update between accessing the first and second bytes of the value.
Also, how are you actually testing the output_toggle?. If (for instance), you have an LED on this line, then the double toggle if both tests are used, would never be visible - the LED would be on for about 1uSec, so with both toggles enabled, the chip would just sit doing apparently nothing....
Best Wishes |
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