Hi Fahmy,
RTFM ! Esp. 3.8 and 3.9.
Where is the ISR prototype in PROJECT1.C ?
Access to TICKS (why all CAPS?) is not made atomic.
Maarten
> Hi listers,
>
> I have problems polling volatile variable from "extern" main(). Here are
> details:
>
> Compiler:
> =======
> I use this distribution: (output from "sdcc -v")
> SDCC : mcs51/gbz80/z80/avr/ds390/pic16/pic14/TININative/xa51/ds400/hc08
> 2.5.6 #4264 (Jul 6 2006)
>
> OS:
> ===
> Win2000
>
> Chip:
> ====
> AT89S52
>
> Simulator:
> =======
> JSIM 4.05 (Freeware from Jens Altmann)
>
> Project files: (details are attached)
> =========
> sys.h
> sys.c
> project1.c
> project2.c
>
> Commands: ( -L and -I paths are stripped)
> =========
> x:/>sdcc -c sys.c
> x:/>sdcc project.c sys.rel
> x:/>packihx project.ihx > project.hex
>
> Problems:
> =======
> When I compiled the project1.c in modular way, with: ( -L and -I paths are
> stripped)
> x:/>sdcc -c sys.c
> x:/>sdcc project1.c sys.rel
> polling volatile variable TIMEOUT from main() is failed.
>
> When I merged "sys.h", "sys.c" in single file "project2.c" and do single
> file compilation,
> x:\sdcc project2.c
> polling volatile variable TIMEOUT from main() is successfull.
>
> Please anyone help me.
> I prefer modular compilation.
> I usually break source files in modules and build them with Borland's make.
>
> Regards,
> Fahmy
>
>
> =====
> SYS.H
> =====
> #define XTAL 11.0592e6
>
> #define TICK_PERIODE 50e-3
> #define RELOAD_VALUE -( TICK_PERIODE * XTAL / 12 )
> #define TMOD_CONF 0x51 // Timer 0: 16-bit timer,
> Timer 1: 16-bit counter
>
> // I stripped "extern" when I merged "sys.c" with "project2.c"
> extern void SystemTick ( void ) interrupt 1 using 1; // timer 0
> extern void LoadDelay ( unsigned int ticks );
> extern void Delay ( unsigned int ticks );
> extern void InitMcu ( void );
>
> volatile unsigned int TICKS; // system ticks
> volatile unsigned char TIMEOUT; // system timeout flag
>
>
> =====
> SYS.C
> =====
> #include <at89x52.h>
> #include "sys.h"
>
> void SystemTick( void ) interrupt 1 using 1 {
> TR0 = 0;
> TL0 = (unsigned char) RELOAD_VALUE;
> TH0 = (unsigned char) ((unsigned int) RELOAD_VALUE >> 8);
> TR0 = 1;
>
> /* system ticks */
> if ( TICKS ) {
> TICKS--;
> return;
> }
> TIMEOUT = 1;
> }
>
> void LoadDelay( unsigned int ticks ) {
> if ( ticks ) {
> TIMEOUT = 0;
> TICKS = ticks;
> }
> }
>
> void Delay( unsigned int ticks ) {
> LoadDelay( ticks );
> while ( !TIMEOUT );
> }
>
> void InitMcu( void ) {
> // Initialize GLOBAL VARs here !
> TICKS = 0;
> TIMEOUT = 1;
>
> // External Interrupt Setting
> IT0 = 0; // falling edge for INT0
> IT1 = 0; // falling edge for INT1
>
> // Interrupt Priority Setting
> PX0 = 0; // Priority to INT 0
> PT0 = 1; // Priority to Timer 0
> PX1 = 0;
> PT1 = 0;
> PS = 0;
> #ifdef AT89x52_H
> PT2 = 0;
> #endif
>
> // Enable specific interrupt(s)
> EX0 = 0; // External 0 interrupt
> ET0 = 1; // Timer 0 interrupt
> EX1 = 0; // External 1 interrupt
> ET1 = 0; // Timer 1 interrupt
> ES = 0; // Serial interrupt
> #ifdef AT89x52_H
> ET2 = 0; // Timer 2 interrupt
> #endif
> EA = 1; // Enable all interrupts
>
> // Timer Setup, see SYS.H
> TMOD = TMOD_CONF;
>
> TL0 = (unsigned char) RELOAD_VALUE;
> TH0 = (unsigned char) ((unsigned int) RELOAD_VALUE >> 8);
>
> TR0 = 1; // run Timer0
> }
>
>
> ==========
> PROJECT1.C
> ==========
> #include <at89x52.h>
> #include "sys.h"
>
> void main( void ) {
> InitMcu();
>
> while ( 1 ) {
> LoadDelay( 10 );
> P1 = 0xff; // leds off
> while( !TIMEOUT );
> LoadDelay( 10 );
> P1 = 0; // leds on
> while( !TIMEOUT );
> }
> }
>
>
> ==================
> PROJECT2.C
> ==================
> #include "sys.c"
>
> void main( void ) {
> InitMcu();
>
> while ( 1 ) {
> LoadDelay( 10 );
> P1 = 0xff; // leds off
> while( !TIMEOUT );
> LoadDelay( 10 );
> P1 = 0; // leds on
> while( !TIMEOUT );
> }
> }
>
>
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