Openwifi crystal ppm needed

[18959263172]

I have design a ad9361/zynq020 board and successful run openwifi with it. on a board with 0.1ppm crystal it works fine. . but with same sdcard, different board with 30PPM crystal.I can't work. does openwifi need high precision crystal,If so ,how precise it need??

[JiaoXianjun]

It is better < 15ppm. In 2.4GHz the frequency offset is around 36kHz. ppm = fo/fc. We haven't tested further than that.
If you turn on the rx dmesg, the last elements represent frequency offset related number: phase_offset.
To calculate actual fo based on that phase_offset number, please refer to

openwifi/user_space/side_ch_ctl_src/iq_capture_freq_offset.py

Line 45 in 7efd067

freq_offset = (20.0e6*phase_offset/LUT_SIZE)/(2.0*3.14159265358979323846)