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Use Packet RSSI formula from datasheet section 5.5.5
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@TheBlueMatt
TheBlueMatt committed Sep 26, 2019
1 parent 30a07a3 commit 68f403b
Showing 1 changed file with 6 additions and 0 deletions.
6 changes: 6 additions & 0 deletions LoRa.cpp
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Expand Up @@ -219,6 +219,12 @@ uint8_t LoRaClass::packetRssiRaw() {

int LoRaClass::packetRssi() {
int pkt_rssi = (int)readRegister(REG_PKT_RSSI_VALUE);
int8_t pkt_snr = ((int8_t)readRegister(REG_PKT_SNR_VALUE));
if pkt_snr < 0 {
pkt_rssi = pkt_rssi * 16 / 15;
} else {
pkt_rssi += pkt_snr / 4;
}
// TODO: change this to look at the actual model code
if (_frequency < 820E6) pkt_rssi -= 7;
pkt_rssi -= 157;
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1 comment on commit 68f403b

@markqvist
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Had to revert this pull request, since it seems that this is not how to do it according to the datasheet. The correction of adding PacketSNR*0.25 should only be applied when the packet is below the noise floor, hence when pkt_snr < 0, you have it the other way around in this code ;)

Also, as I read the datasheet, the 16/16*rssi slope correction in the datasheet should be applied only when RSSI is above -100 dBm, and here you do the correction when pkt_snr < 0.

But thanks so much for pointing it out anyway. I think I choose to forego the slope adjustment originally, since it's not adding that much precision anyways, but I'll add it now anyways, since I just looked it all through.

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