USRP2: PPS interrupt handler?

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():

 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?

Thanks for any help!

John B.

john brzustowski wrote:


/* 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