I've bought some time ago 8051 learning kit with monitor in ROM and 8k
external ram starting at 0x8000h, where programs in intel hex format are
load to external RAM via RS232
if i want to start this program i have to press 0 and type address 8000
(where the program is), then the program is running
Now i have a problem, i trying many things to make it come working like i
want, but i didn't make it.
Below i've pasted code. I want to run any of interrupts (1 or/and 3). In
belowe code it doesn't work, why?
Could someone show me my mistake which i doing? Perhaps I forgot about
someting or make it in wrong order?
Running this code i get nothng on LED display, if i remove lines from TMOD
to TR0 it will display a 0 on first LED display. Otherwise it will wont work
why?


#include "8051.h"

//adresses where are LED display
xdata at 0x4000 unsigned char liczba;
xdata at 0x4001 unsigned char wyswietlacz;

//digits definition
#define c0 0x01 | 0x02 | 0x04 | 0x08 | 0x10 | 0x20
#define c1 0x02 | 0x04
#define c2 0x01 | 0x02 | 0x40 | 0x10 | 0x08
#define c3 0x01 | 0x02 | 0x40 | 0x04 | 0x08
#define c4 0x20 | 0x40 | 0x02 | 0x04
#define c5 0x01 | 0x20 | 0x40 | 0x04 | 0x08
#define c6 0x01 | 0x20 | 0x40 | 0x04 | 0x08 | 0x10
#define c7 0x01 | 0x02 | 0x04
#define c8 0x01 | 0x02 | 0x04 | 0x08 | 0x10 | 0x20 | 0x40
#define c9 0x01 | 0x20 | 0x40 | 0x02 | 0x04 | 0x08 | 0x047
#define kr 0x80

char tab[11]={c0,c1,c2,c3,c4,c5,c6,c7,c8,c9,kr};
unsigned char zn,cnt;

void obsluga(void) interrupt 1; //handle of int T0
void obslug2(void) interrupt 3; //handle of int T1

void main(void)
{
cnt = 0; //setting starting LED segment
zn = 0; //setting starting digit
TMOD = 17; //T0 & T1 16bit

//seting timers T1 i T0
TH1 = 0x80;
TL1 = 0;
TH0 = 0;
TL0 = 0;
//***

ET1 = ET0 = EA = 1; //accept int from T0, T1 and globally
TR1 = 1; // 1 starting timer T1 - 0 stopping
TR0 = 1; // 1 starting timer T0 - 0 stopping


while(1) //loop to infinitive
{
wyswietlacz = cnt; //which LED to activate
liczba = tab[zn]; //which digit to display
liczba = 0; //turn off digit

}
}

void obsluga(void) interrupt 1
{

TR0 = 0; //stop timer T0
TH0 = 0; //set older bits
TL0 = 0; //set younger bits
zn++; //change on next
if (zn>9) zn=0;
TR0 = 1; //starts timer T0
}

void obslug2(void) interrupt 3
{
TR1 = 0; //stop timer T1
cnt++; //change display on which will by digit displayed

TH1 = 0x80; //set timet
TL1 = 0; //set timet
TR1 = 1; //starts timer T1
}

Lukas wrote:
-
Could you explain how these two instructions work?
Is there a specific protocol, why do you write
a 0 just after the digit?

Uzytkownik "Lanarcam" <lanarcam1@yahoo.fr> napisal w wiadomosci
news:1122215949.286600.24830@g49g2000cwa.googlegro ups.com...
this is for turn off the display
i know that this is done badly but i'll correct this when the iterrupts will
work
first i have to clear all LEDs display
2nd i have to write a digit wich i wat to display
then show the nr of diplay on wich it should aper

I was using 8051s before I move to AVR.

Anyway, I'm not sure, do interrupt 1 IS Timer0 overflow interrupt (or
interrupt 3 IS Timer1overflow interrupt) ? Usually I get that wrong
(so my interrupt handler handles wrong interrupt).

Another mistake that I usually had is forgetting not to activated
global/timer overflow interrupt. I see that you have done it, so
there's no mistakes.

Probably you need to read your monitor's firmware documentation.

Some monitors use timer overflow interrupt as switching task timer
tick. So it can switch from user program to monitors program. It's
quite normal in embedded OS.

If I may suggest, you should try bare development boards (where it has
no monitor firmware in it). You'll get much more experience and fun =D