Hi guys,
Several months ago I accidentally stumble across interesting thing: if SPI bus initialised on ~8Mhz, then sx127x chips in FSK mode introduce delay. Cause invalid data transmitted between MCU and sx127x chip.
I did some analysis under different conditions:
- LoRa vs FSK mode. LoRa mode seems fine.
- Lower SPI frequencies: 2Mhz seems fine, some delay on 4Mhz and more than half tick delay on 8Mhz
- Same delay on Heltec V2 (ESP32) and on Ra-02 ( Raspberry PI).
- Mitigates only when long run of "1"s is transmitted (0xFF)
Seems like hardware bug? Anyone saw this before?
