[LinuxPPS] Problem: only clear edge is detected

[Rodolfo Giometti]

On 28/03/23 15:16, Charbonneau, André wrote:
> Hi,

Hello.

[snip]

> But as you can see from the output above, **only the clear edge is captured**, 
> not the assert edge.  I looked at the pulse with a scope and the pulse is a 
> positive pulse (leading edge is rising edge), 5.55Vpp.  I don’t understand why 
> it would detect the clear edge, but not the assert edge.

Which is the duty cycle?

> $ cat /etc/udev/rules.d/09-pps.rules
> 
> KERNEL=="pps0", OWNER="root", GROUP="root", MODE="0644"
> 
> KERNEL=="ttyS0", RUN+="/bin/setserial -v /dev/%k low_latency irq 4"

Take a look at irq 4 and check how many interrupts the system receives in a 
second. They should be 2 for both assert and clear events.

Ciao,

Rodolfo

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