Is it a good idea to use a usb-serial adapter for PPS? Yes, it is.

[Hans Petter Selasky]

On 2019-08-20 13:38, Per Hedeland wrote:
> 
> This sounds like a method to determine a fixed latency - or am I
> misunderstanding?

The HC sends out a timestamp, called SOF, to all USB devices every 1ms 
or 125us. This SOF mark is usually the beginning of the polling 
schedule. All USB endpoints are polled by the HC. The USB device can 
predict the time of the SOF and also completion on the HC and so I 
believe adjust the timestamp, so that it would appear to be received 
instantaneously.

--HPS