Hi ,
Thanks alot Mr. Oleg Sergeev now in assembly program i'm getting the sharp pulse for both the external interrupts.
I want to use these interrupts to receive/transmit data using sync modem.
Now same i want same in C program using C51 compiler . Following is the C code i have written but
that is not working.I'm using evaluation version of Keil Compiler . I have following
doubts about ISR in C
1. Do we need to enable and disable the interrupt in its ISR to prohibit it to interrupt
unless its ISR is over.
2. It it necessary to specify the register bank ( using 1 ..... etc )
3. To set serial port baud rate do we need to set TCON regs , default C51 setting is
sufficient or not.
4. Do I need to modify startup.a51 file for this code.

Can anybody suggest me any other way to control sync modem ( source code or any url ) ?

thaks
Sanjay


/*;Program to Transmit data to GMSK CMX469 Modem
;Int0 -> Applied RxSync clock used for data sending P3.2
;Int1 -> Applied Txsync clock used for data receiving P3.3
;P1.0 -> Tx data
;P1.1 -> Rx data
;P1.2 -> Carrier Detect
*/
#include <reg51.h>
#include <stdio.h>
//void ReceiveData(void); //to be called by interrupt ISR
//void TransmitData(void); //to be called by interrupt ISR

void InitializeInterrupts(void);
void InitSerialPort(void);
static void INT0_ISR (void); //RX Sync clock
static void INT1_ISR (void); //TX sync clock
void main()
{
InitSerialPort();
InitializeInterrupts();
while(1)
{ P0=0xff; P2=0xff; }
}
static void INT1_ISR (void) interrupt 2 using 1 //for tx
{
EX1=0; //disable int1
P2=0x00; // making it zero to know whether intr has ocured on falling edge
// TransmitData(); //function to tranmit data
EX1=1; //enable int1
}
static void INT0_ISR (void) interrupt 0 using 1 //for receive
{
EX0=0; //disable int0
P0=0x00; // making it zero to know whether intr has ocured on falling edge
//ReceiveData(); //function to receive data
EX0=1; //enable int0
}
void InitializeInterrupts(void)
{
EX0=1;
IT0=1; //falling edge
EX1=1;
IT1=1; //falling edge
EA=1;
}
void InitSerialPort(void)
{
SCON = 0x52; /* SCON */ /* setup serial port control */
TMOD = 0x20; /* TMOD */ /* hardware (9600 BAUD @12MHZ) */
TCON = 0x69; /* TCON */
TH1 = 0xfd; /* TH1 */ //9600 baud rate
TR1=1;
printf("nModem Program is runningn");
}