I'm using two arduino boards that intercommunicate via SPI.
One regular UNO, second - Anarduino Wireless LoRa RF98W.
In the attached test sketches master sends a number to slave, slave modifies it and returns to master.
These programs work properly when Anarduino serves as a master, however when Anarduino becomes a slave, a master receives zeros.
What do I miss?