Urgent: Problem in Timer interrupt program using AT91SAM7SE512-EK]

Hi friend,

Thanks for your reply,
Actually this same source code is working prperly in IAR workbench Tool.
In keil tool only giving the problem.
i have downloaded this example source code from www.atmel.com/.../product_card.asp
website.

The problem is when i give the input to board,the receiver interrupt receive the data and transmit to the USART0.
After that the program is getting hang.
Means the control goes to receiver interrupt function only once and should not return from it.

Please help me to rectify this problem.

With regards,
Murthy.R

Hi friend,

Thanks for your reply,
Actually this same source code is working prperly in IAR workbench Tool.
In keil tool only giving the problem.
i have downloaded this example source code from www.atmel.com/.../product_card.asp
website.

The problem is when i give the input to board,the receiver interrupt receive the data and transmit to the USART0.
After that the program is getting hang.
Means the control goes to receiver interrupt function only once and should not return from it.

Please help me to rectify this problem.

With regards,
Murthy.R

Why looking for IAR examples instead of Keil examples?

Also, the code did not match the contents of the AT91SAM7SE512_IAR.zip file - that ISR do look as expected for a UART ISR.

In a UART ISR, you send characters by putting them in the transmit register of the UART - you don't call a PutChar function, unless the PutChar function specifically inserts a character into another UART's transmit queue, for that UART's ISR to later pick up and send.

Hi friend,
Thanks for your Reply.
I am new to this AT91SAM7SE512.So please help me on this UART RXD interrupt problem.
This is my UART0 initialization code.
Do i have to modify anything in this code.Because if i give this line "AT91C_BASE_AIC->AIC_IECR = 0x1 << AT91C_ID_US0;"the program(blink one LED) is not working.When i disable this line the LED blinking is working.And also the Transmission is working good.

Please advise me on this.

#define AT91C_US_ASYNC_MODE ( AT91C_US_USMODE_NORMAL + \ 
                        AT91C_US_NBSTOP_1_BIT + \ 
                        AT91C_US_PAR_NONE + \ 
                        AT91C_US_CHRL_8_BITS + \ 
                        AT91C_US_CLKS_CLOCK )
#define BAUD_VALUE(baud_rate) (((( MCK  / (baud_rate * 16)) * 10) % 10) < 5 ? \ 
                                                                                                        (MCK / (baud_rate * 16)) : \ 
                                                                                                        (MCK / (baud_rate * 16)) + 1  )



void uart0Init(void)
{
     // enable the clock of UART0
     AT91C_BASE_PMC->PMC_PCER = (1<<AT91C_ID_US0);
     // enable uart pins on PIO
     *AT91C_PIOA_PDR = AT91C_PA5_RXD0 | AT91C_PA6_TXD0;
     // select peripheral connection
     *AT91C_PIOA_ASR = AT91C_PA5_RXD0 | AT91C_PA6_TXD0;
     // disable I/O pullup
      *AT91C_PIOA_PPUDR = AT91C_PA5_RXD0;
     // reset the UART
     AT91C_BASE_US0->US_CR = AT91C_US_RSTRX | AT91C_US_RSTTX | AT91C_US_RXDIS |AT91C_US_TXDIS;
     // set serial line mode
     AT91C_BASE_US0->US_MR = AT91C_US_ASYNC_MODE;
     // set the baud rate
     AT91C_BASE_US0->US_BRGR = BAUD_VALUE(9600);
     // enable the uart
    AT91C_BASE_US0->US_CR = AT91C_US_RXEN | AT91C_US_TXEN;

        // enable reaction on different interrupt sources
        AT91C_BASE_US0->US_IDR = 0xFFFFFFFF;
        AT91C_BASE_US0->US_IER = AT91C_US_RXRDY;

        // configure USART0 interrupt
        AT91C_BASE_AIC->AIC_IDCR = 0x1 << AT91C_ID_US0;
        AT91C_BASE_AIC->AIC_SVR[AT91C_ID_US0] = (unsigned long) Usart0Int;
        AT91C_BASE_AIC->AIC_SMR[AT91C_ID_US0] = AT91C_AIC_SRCTYPE_HIGH_LEVEL |2;
        AT91C_BASE_AIC->AIC_IECR = 0x1 << AT91C_ID_US0;


}

With Regards and Thanks

Murthy.R

Because if i give this line "AT91C_BASE_AIC->AIC_IECR = 0x1 << AT91C_ID_US0;"the program(blink one LED) is not working.

This line actually "enables" the USART0 interrupt. If your program does not work when you do that, then your USART0 interrupt service routine is the most likely culprit.

Please help me to rectify this problem

With regards
Murthy.R

You posted a link to the Atmel site, but haven't mentioned exactly what code you decided to try to use.

Your posted code for the UART ISR does not look anything like the example code available - neither for IAR nor for Keil.

Where did you get it?

How have you modified it?

I did look at the code in "AT91SAM7SE512_IAR.zip" and "AT91SAM7SE512_KEIL.zip", and both contains UART ISR code that looks like I would expect them to. Your posted code looks very much like a criss/cross between polled and interrupt-driven operation with their GetChar and PutChar references.

I commented on it earlier, but didn't get a response about it.

hi,
i have downloaded the "AT91SAM7SE512_KEIL.zip"code.
i took a "AT91SAM7SE-Interrupt" as a example code and created a new project(using keil version 3.53).
Then I tried that code,the transmission has no problem,
but RXD is not working.

Those putchar and getchar are used ISR in that example code.

After that i have developed a new code without using the APIs(what i posted here).

Please advise me on this.

With regards,
Murthy.R

Your code is not identical to the one you quotes.
This is the code on the Atmel site:

void Usart_c_irq_handler(void)
{
        AT91PS_USART USART_pt = AT91C_BASE_US0;
        unsigned int status;
        //* get Usart status register
        status = USART_pt->US_CSR;
        if ( status & AT91C_US_RXRDY){
                //* Get byte and send
                AT91F_US_PutChar (USART_pt, AT91F_US_GetChar(USART_pt));
        }

        if ( status & AT91C_US_OVRE) {
                //* clear US_RXRDY
                 AT91F_US_GetChar(USART_pt);
                 AT91F_US_PutChar (USART_pt, 'O');
        }

        //* Check error
        if ( status & AT91C_US_PARE) {
                 AT91F_US_PutChar (USART_pt, 'P');
        }

        if ( status & AT91C_US_FRAME) {
                 AT91F_US_PutChar (USART_pt, 'F');
        }

        if ( status & AT91C_US_TIMEOUT){
                USART_pt->US_CR = AT91C_US_STTTO;
                 AT91F_US_PutChar (USART_pt, 'T');
        }

        //* Reset the satus bit
         USART_pt->US_CR = AT91C_US_RSTSTA;
}

It uses a USART_pt pointer, and doesn't have any acknowledge code for the interrupt. Also, maybe you should reset the status bit before acknowledning the interrupt?

Another thing - there is different example code for the UART in the USART_USB sample project. That ISR code looks like:

void Usart_c_irq_handler(void)
{
        AT91PS_USART USART_pt = COM0;
        unsigned int status;

        //* get Usart status register and active interrupt
        status = USART_pt->US_CSR ;
        status &= USART_pt->US_IMR;

        if ( status & AT91C_US_RXBUFF){
        //* Toggel LED
        Trace_Toggel_LED( AT91B_LED1) ;
        //* transfert the char to DBGU
         if ( first == 0){
             COM0->US_RPR = (unsigned int) buff_rx1;
             COM0->US_RCR = 100;
             pCDC.Write(&pCDC, buff_rx,100);
             first =1;
           }else{
             COM0->US_RPR = (unsigned int) buff_rx;
             COM0->US_RCR = 100;
             pCDC.Write(&pCDC, buff_rx1,100);
             first=0;
           }
        }
//* Check error

        if ( status & AT91C_US_TIMEOUT){
         Trace_Toggel_LED( AT91B_LED2) ;
         status = 100 - COM0->US_RCR;
         if  (status !=0){
           if ( first == 0){
                COM0->US_RPR = (unsigned int) buff_rx1;
                COM0->US_RCR = 100;
                pCDC.Write(&pCDC, buff_rx,status);
                first =1;
           }else{
                COM0->US_RPR = (unsigned int) buff_rx;
                COM0->US_RCR = 100;
                pCDC.Write(&pCDC, buff_rx1,status);
                first=0;
            }
            COM0->US_CR = AT91C_US_STTTO;
          }
        }
        //* Reset the satus bit for error
         USART_pt->US_CR = AT91C_US_RSTSTA;
}

Hi friend,

I have taken the first example(US0),
the second one is Debug port.

In the ISR i have included this lines(at the end).
The result is same(No receving).

        AT91C_BASE_AIC->AIC_EOICR = AT91C_BASE_US0->US_CSR;               /*  Interrupt Ack*/
        AT91C_BASE_AIC->AIC_ICCR  = (1 << AT91C_ID_US0);                       /*  Interrupt Ack*/
        AT91C_BASE_AIC->AIC_EOICR = 0;


        AT91C_BASE_US0->US_CR = AT91C_US_RSTSTA;

With regards,
Murthy.R

Hi friends,

Please give me any example code for USART receiver interrupt function(for KEIL uversion 3.53).

Please help me.

with regards,
Murthy.R