Unable to hit inerrupt when changing the value in registers in debug mode.

satish kammili

I am using "TM4C123GH6PM" and written UART program using interrupt. When any key is pressed it will echo the key pressed.
The issue is i am unable to see the interrupt hit when i change the value in register "UART0_UART_DR" through register view in debug mode, but when i enter any key using hyper terminal it is working as expected.

over 10 years ago

0 Biser Gatchev-XID over 10 years ago

TI__Guru**** 393215 points

Moving this to the correct forum.

0 f. m. over 10 years ago

Guru 11940 points

I think you need to understand that debuggers are intrusive.

Most debuggers read memory/registers (who's view is open) upon hitting a breakpoint, or single stepping. And reading serial RX registers usually clears the associated interrupt flag. That can definitely alter your code path. Rather put a breakpoint after reading the DR register in your code.

0 Randy Ott over 10 years ago

Intellectual 750 points

What interrupt are you expecting to see? What interrupts are enabled, RX, TX, or both?

Randy

0 Amit Ashara over 10 years ago

TI__Guru**** 244400 points

Hello Satish,

The UART DR register is a Read register in the RX Path. So when a byte is written to it, the Read of the register will not show that byte in TXFIFO but the current byte in RXFIFO.

Regards
Amit

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Unable to hit inerrupt when changing the value in registers in debug mode.