Not seeing TI_0 interrupt flag when sending serial data mode 0

Hi Anand,

Thank you for your reply.  ISR_UART0() is in a seperate c file (isr.c) due to the #pragma NOIV directive in periph.c.  I was assuming the compiler would generate the appropriate code automatically so the function would be called on interrupt 4 (0x0023) based on the function's definition:

void ISR_USART0(void) interrupt 4

Within TD_Init() I then set bit 4 (ES0) in IE to enable the serial port 0 interrupts.

The interrupt does seem to be working in some fashion, given that LED2 turns on, however in further testing, I've discovered that the device stops responsing over USB once I try sending data serially.  If I disable the serial interrupt, the issue goes away and the device responds normally after sending serial data.

I've attached the project code.  The EZ-USB Interface in CyConsole can be used to send a Vendor Request 0x40 to trigger the sending of the byte over serial.

Thanks,

Ben

Whoops, figures I would miss that.  It should be attached here.  I will try the bit addressable method and see what happens there.

-Ben

Hmm, file attachement didn't work a second time.  I'm this time with IE in case there's an odd issue using Firefox.

Crazy, the bit addressable method seems to have been the key.  Changing ISR_UART0() to the following produces the results I would expect, LED2 and LED4 turn on and the device continues to respond to USB commands.

void ISR_USART0(void) interrupt 4
{
    unsigned char temp;

    temp = LED2ON;

    if (RI != 0)
    {
        temp = LED3ON;
        RI = 0;
    }

    if (TI != 0)
    {
        temp = LED4ON;
        TI = 0;
    }
}

Is there any explanation for this kind of behaviour?  I was under the impression that the bit-addressable SFRs were there almost as a convience/save a few cycles kind of thing but not required.  In any case, it seems to be working now.  Thanks for your help Anand!

-Ben