Additional pps-gpio

Hal Murray hmurray at
Sun Jan 28 07:37:05 UTC 2018

> But maybe I don't understand what you're after. 

I'm interested in learning whatever we can about the timing in the kernel PPS 

There is another approach that might be interesting.  Use a loopback on some 
modem control signals or gpio pins.  Then a test program can grab the time, 
flap the pin, and grab the time, then read the PPS time.

Things may get complicated by locks in the kernel.  If they get too ugly, we 
could use two machines and ping-pong back and forth.  It would take a bit of 
work to merge the data and correct for the time offset between the two 
systems.  That would work better with identical systems.

> Well, that assumes you do have a serial port available that even has these
> signals connected. 

I'm interested in both GPIO and modem signals on PCs with real serial ports.  
I have PCs with multiple serial ports.  It may be easier for me to work with 
them rather than learn how to drive the GPIO pins on a Raspberry Pi.

These are my opinions.  I hate spam.

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