Re: [Discuss-gnuradio] USRP2: PPS interrupt handler?

[Matt Ettus]

john brzustowski wrote:
> Does the current USRP2 FPGA/firmware release allow for a PPS interrupt
> handler?  I've tried adding these lines to the txrx.c firmware app:
>
>    static void
>    test_pps_handler(unsigned irq)
>    {
>      putstr("Got to PPS handler at time:");
>      puthex32_nl(timer_regs->time);
>      pic_regs->pending = PIC_PPS_INT;
>    }
>
>    ...
>      /* inside main() */
>      pic_register_handler(IRQ_PPS, test_pps_handler);
>      putstr("\nRegistered pps interrupt handler\n");
>
> Sending a pulse into the PPS SMA port doesn't trigger the handler.
> Based on fragments I found in the mailing lists, 
> I also tried including these lines inside main():

The pps interrupt is currently disabled in the FPGA, commented out in 
timing/time_sync.v

We can re-enable it if you need, or you can build your own fpga with 
that piece of logic included.

>      clocks_mimo_config(MC_WE_LOCK_TO_SMA);
>      timesync_regs->tick_control |= TSC_TRIGGER_EVERYPPS;
>
> but that changed nothing.  Am I doing something wrong, or is this
> unsupported?

Those won't affect what you're trying to do.

Matt