From 02ac97b07ef4910aa41c162236bcf0fcb569aaff Mon Sep 17 00:00:00 2001
From: jgromes <jgromes@users.noreply.github.com>
Date: Sun, 29 Dec 2019 12:21:14 +0100
Subject: [PATCH] [SX126x] Added option to change sleep mode (cold/warm start)

---
 src/modules/SX126x/SX126x.cpp | 8 ++++++--
 src/modules/SX126x/SX126x.h   | 4 +++-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/modules/SX126x/SX126x.cpp b/src/modules/SX126x/SX126x.cpp
index ffd84d44..33d7fcb7 100644
--- a/src/modules/SX126x/SX126x.cpp
+++ b/src/modules/SX126x/SX126x.cpp
@@ -370,8 +370,12 @@ int16_t SX126x::scanChannel() {
   return(ERR_UNKNOWN);
 }
 
-int16_t SX126x::sleep() {
-  uint8_t data[] = {SX126X_SLEEP_START_COLD | SX126X_SLEEP_RTC_OFF};
+int16_t SX126x::sleep(bool retainConfig) {
+  uint8_t sleepMode = SX126X_SLEEP_START_WARM;
+  if(!retainConfig) {
+    sleepMode = SX126X_SLEEP_START_COLD;
+  }
+  uint8_t data[] = {sleepMode | SX126X_SLEEP_RTC_OFF};
   int16_t state = SPIwriteCommand(SX126X_CMD_SET_SLEEP, data, 1, false);
 
   // wait for SX126x to safely enter sleep mode
diff --git a/src/modules/SX126x/SX126x.h b/src/modules/SX126x/SX126x.h
index ff282cca..bfcccbfa 100644
--- a/src/modules/SX126x/SX126x.h
+++ b/src/modules/SX126x/SX126x.h
@@ -452,9 +452,11 @@ class SX126x: public PhysicalLayer {
     /*!
       \brief Sets the module to sleep mode.
 
+      \param retainConfig Set to true to retain configuration of the currently active modem ("warm start") or to false to discard current configuration ("cold start"). Defaults to true.
+
       \returns \ref status_codes
     */
-    int16_t sleep();
+    int16_t sleep(bool retainConfig = true);
 
     /*!
       \brief Sets the module to standby mode (overload for PhysicalLayer compatibility, uses 13 MHz RC oscillator).