Lora SX1278 with RADXA ZERO 3W

ROCK 3 Series ZERO 3W/3E
1

I’m trying to get a SX1278 LoRa module working with the Adafruit RFM9x but don’t succeed.
Have enabled the spi overlay, seems to work, lora modules are working on a raspberry but no joy on the radxa. Are there working setups, configs or specifics to deal with?
Latest I’ve tried this pin layout:
VCC Pin 1
GND Pin 6
SCK Pin 23
MISO Pin 21
MOSI Pin 19
NSS (CS) Pin 29
RESET Pin 31
DIO0 (IRQ) Pin 28
several different errors from RuntimeError: Failed to find rfm9x with expected version – check wiring
to busy…

2

a bit more detailed info:

I’ve successfully used the same module on a Raspberry Pi , but on the Radxa I consistently get:
RuntimeError: Failed to find rfm9x with expected version – check wiring
or : OSError: [Errno 16] Device or resource busy

What I’ve already done:

  • Enabled the SPI3 overlay: rk3568-spi3-m1-cs0-spidev.dtbo
  • /dev/spidev3.0 is available and working (tested with spidev)
  • Verified pinout multiple times, based on the Radxa GPIO docs and logic analyzer
  • Tried multiple SX1278 modules (known working on Pi)
  • Slowed SPI speed down to 10 kHz
  • Bypassed reset logic ( reset=None )
  • Manually read VERSION register ( 0x42 ) over SPI → always returns 0x00,
    only the first time a got a different anwer XX, 0. (can’t remember anymore)