From 83f097e5c31175d2698c2c72a79d1ba2800cd4a1 Mon Sep 17 00:00:00 2001
From: Manvendra Singh <16uec063@lnmiit.ac.in>
Date: Fri, 20 Sep 2019 13:39:32 +0530
Subject: [PATCH] RSSI when snr>0

Due to linearity issues, we do (RSSI=-139+16/15*PacketRssi) [https://www.mouser.com/ds/2/761/sx1276-1278113.pdf, Section 5.5.5 Note-3]
---
 src/LoRa.cpp | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/LoRa.cpp b/src/LoRa.cpp
index 6eb3d22..2371559 100644
--- a/src/LoRa.cpp
+++ b/src/LoRa.cpp
@@ -256,9 +256,17 @@ int LoRaClass::parsePacket(int size)
 
 int LoRaClass::packetRssi()
 {
-  return (readRegister(REG_PKT_RSSI_VALUE) - (_frequency < 868E6 ? 164 : 157));
+int8_t snr =  ((int8_t)readRegister(REG_PKT_SNR_VALUE)) * 0.25;
+int8_t rssi =  readRegister(REG_PKT_RSSI_VALUE);
+
+  if(snr>0)
+  return (rssi + ( rssi >> 4 ) + snr - (_frequency < 868E6 ? 164 : 157)); 
+  
+  else
+  return (rssi + (rssi >> 4) - (_frequency < 868E6 ? 164 : 157));
 }
 
+
 float LoRaClass::packetSnr()
 {
   return ((int8_t)readRegister(REG_PKT_SNR_VALUE)) * 0.25;