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Vincent_F's avatar
Vincent_F
Icon for New Contributor rankNew Contributor
1 year ago

UART gets stuck when enabling IRQ (NIOS II)

Hi, I'm reopening an old post from 2013 that apparently never got a reply. I'm facing the same problem. I have a small NIOS II system (used as a demo for my students) that features a jTAG UART an...
Nios Cpu
tehjingy_Altera's avatar
tehjingy_Altera
Icon for Regular Contributor rankRegular Contributor
1 year ago

Hi


Sorry for the slow response.

Kept going through your code and it looks fine.

I found out that you are accessing the JTAG UART.

It is slightly different from the UART IP.


The control registers are different compared to the UART IP.

https://www.intel.com/content/www/us/en/docs/programmable/683130/24-1/control-register-17391.html


Could you try the following code to register the interrupt ?


sp->irq_enable = ALTERA_AVALON_JTAG_UART_CONTROL_RE_MSK;

IOWR_ALTERA_AVALON_JTAG_UART_CONTROL(sp->base, sp->irq_enable);

alt_ic_isr_register(irq_controller_id, irq, altera_avalon_jtag_uart_irq, sp, NULL);



Regards

Jingyang, Teh


  • Vincent_F's avatar
    Vincent_F
    Icon for New Contributor rankNew Contributor
    1 year ago

    Hi Jingyang, Teh,

    No worries, we're all busy.

    Thanks for your reply! Yet, the problem has nothing to do with the JTAG UART (i.e. the IRQ for this IP is never registered nor unregistered) I use it as my stdio interface.

    The problem occurs on the RS232 UART (RFS2 UART in my project), i.e. when I enable/disable the IRQ on this interface.

    Best regards

    Vincent