I’m attempting to use a Heltec lora ESP32 dev kit v2 with oled to receive data from an ESP32 connected to a RYLR896 module. Arduino IDE.
The Heltec code is based on the Heltec example OLED_LORA_Receiver sketch.
The ESP32 with the RYLR module sketch uses Hardware serial port 2 to send AT commands to the RYLR896, and doesn’t use a LoRa library.
So far, I’m not able to receive data on the heltec module that is sent by the RYLR896.
The RYLR896 Frequency Band, Spreading factor, Bandwidth, and coding rate are set at 915E6, SF7, 125kHz, and coding rate 1 (which appears to be CRC4/5). The “Preprogrammed Preamble” is set to 4.
Since the heltec receive sketch uses Lora.h, I used the following methods:
LoRa.setCodingRate4(4); //I believe this is CRC4/5
LoRa.setPreambleLength(128);// - have also tried 16,32,64, 65536
LoRa.setSignalBandwidth(125E3);
LoRa.setSpreadingFactor(7);
LoRa.setSyncWord(0);
The RYLR has settings for NetworkID and device Address – which seems to be a LoRaWAN thing, not lower level LoRa. network address is set to 0 (“public”), and I’m sending with a destination address of 0 (broadcast). I haven’t been able to find these setting on the Heltec Lora module. My guess is that the RYLR protocol is somewhere between LoRa and LoRaWAN.
There are (at least) two other things that don’t seem to match up:
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“Preprogrammed Preamble” with valid range 4-7 on the RYLR896 and Preamble length with valid range 6-65535 on the Heltec module implementation. The semtech datasheet says the preamble length should be set the same on Tx and RX or the window needs to be larger on the receiver than on the tx in order to decode it. How does Preprogrammed Preamble corelate to Preamble Length? Surely Reyax isn’t changing the bit sequence 10101010… of the preamble…? Is this the number of bits in Reyax’s Preamble length? Is there a way to get to the sx1276 registers directly to read them or write to them?
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Syncword is not a published setting in the RYLR AT command set. The SX1276 (used in RYLR896) has default syncword=0x00, so I think these are set the same.
Apart from - “don’t use Reyax,” any suggestions for making these dudes talk?