Re: [Discuss-gnuradio] Using USRP Clock for Timers

2016-06-09 Thread Marcus Müller
Hi Devin, On 09.06.2016 15:27, devin kelly wrote: > A different approach makes sense. What I need this for is doing some > book keeping when certain frame/slots occur. This sounds a lot like you should be doing this based on when a certain sample flies by – and not at a certain "CPU time". > Sinc

Re: [Discuss-gnuradio] Using USRP Clock for Timers

2016-06-09 Thread devin kelly
A different approach makes sense. What I need this for is doing some book keeping when certain frame/slots occur. Since I have a TDMA system, I need to make sure the metadata (e.g. tx_time tag) I apply to my packets is in sync with the radio time. Additionally, the receive time is important to m

Re: [Discuss-gnuradio] Using USRP Clock for Timers

2016-06-08 Thread Marcus Müller
Hi Devin, this won't work out for the simple reason that timed commands happen in the FPGA on the USRP, and C++ happens in your PC, and the coupling between both is loose at best – there's always some random latency bus (network, USB,…) between the USRP and the host, and hence, these two clocks ne

[Discuss-gnuradio] Using USRP Clock for Timers

2016-06-08 Thread devin kelly
Hello, For my applications the MAC layer of my waveform requires me to implement a few timers (e.g. for slot and frame times, etc). What I'd like to do is exclusively use the USRP clock for these timers. I've tried mixing the system clock and the USRP clock before (see a few messages on this list