From f0e686eaa959f1e0b796fd10cb051d4ba2691b9f Mon Sep 17 00:00:00 2001
From: jgromes <jan.gromes@gmail.com>
Date: Fri, 14 Mar 2025 20:14:52 +0100
Subject: [PATCH] [Si443x] Add CRC configuration (#1430)

---
 src/modules/Si443x/Si443x.cpp | 17 ++++++++++++++---
 src/modules/Si443x/Si443x.h   |  9 +++++++++
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/src/modules/Si443x/Si443x.cpp b/src/modules/Si443x/Si443x.cpp
index cf88f7a3..b121635a 100644
--- a/src/modules/Si443x/Si443x.cpp
+++ b/src/modules/Si443x/Si443x.cpp
@@ -54,10 +54,13 @@ int16_t Si443x::begin(float br, float freqDev, float rxBw, uint8_t preambleLen)
   state = packetMode();
   RADIOLIB_ASSERT(state);
 
-  state = setDataShaping(0);
+  state = setDataShaping(RADIOLIB_SHAPING_NONE);
   RADIOLIB_ASSERT(state);
 
-  state = setEncoding(0);
+  state = setEncoding(RADIOLIB_ENCODING_NRZ);
+  RADIOLIB_ASSERT(state);
+
+  state = setCRC(true);
   RADIOLIB_ASSERT(state);
 
   state = variablePacketLengthMode();
@@ -293,7 +296,8 @@ int16_t Si443x::startReceive() {
   this->mod->setRfSwitchState(Module::MODE_RX);
 
   // set interrupt mapping
-  this->mod->SPIwriteRegister(RADIOLIB_SI443X_REG_INTERRUPT_ENABLE_1, RADIOLIB_SI443X_VALID_PACKET_RECEIVED_ENABLED | RADIOLIB_SI443X_CRC_ERROR_ENABLED);
+  uint8_t irq = this->crcEnabled ? (RADIOLIB_SI443X_VALID_PACKET_RECEIVED_ENABLED | RADIOLIB_SI443X_CRC_ERROR_ENABLED) : RADIOLIB_SI443X_VALID_PACKET_RECEIVED_ENABLED;
+  this->mod->SPIwriteRegister(RADIOLIB_SI443X_REG_INTERRUPT_ENABLE_1, irq);
   this->mod->SPIwriteRegister(RADIOLIB_SI443X_REG_INTERRUPT_ENABLE_2, 0x00);
 
   // set mode to receive
@@ -654,6 +658,13 @@ int16_t Si443x::clearIrqFlags(uint32_t irq) {
   return(RADIOLIB_ERR_NONE);
 }
 
+int16_t Si443x::setCRC(bool enable, bool mode) {
+  this->crcEnabled = enable;
+  uint8_t crcEn = enable ? RADIOLIB_SI443X_CRC_ON : RADIOLIB_SI443X_CRC_OFF;
+  uint8_t crcCfg = mode ? RADIOLIB_SI443X_CRC_IBM_CRC16 : RADIOLIB_SI443X_CRC_CCITT;
+  return(this->mod->SPIsetRegValue(RADIOLIB_SI443X_REG_DATA_ACCESS_CONTROL, crcEn | crcCfg, 2, 0));
+}
+
 Module* Si443x::getMod() {
   return(this->mod);
 }
diff --git a/src/modules/Si443x/Si443x.h b/src/modules/Si443x/Si443x.h
index 42ddc9e7..a5e843dd 100644
--- a/src/modules/Si443x/Si443x.h
+++ b/src/modules/Si443x/Si443x.h
@@ -836,6 +836,14 @@ class Si443x: public PhysicalLayer {
     */
     int16_t clearIrqFlags(uint32_t irq) override;
 
+    /*!
+      \brief Enables/disables CRC of transmitted or received packets.
+      \param enable Enable (true) or disable (false) CRC.
+      \param mode Set CRC mode
+      \returns \ref status_codes
+    */
+    int16_t setCRC(bool enable, bool mode = false);
+
 #if !RADIOLIB_GODMODE && !RADIOLIB_LOW_LEVEL
   protected:
 #endif
@@ -858,6 +866,7 @@ class Si443x: public PhysicalLayer {
     size_t packetLength = 0;
     bool packetLengthQueried = false;
     uint8_t packetLengthConfig = RADIOLIB_SI443X_FIXED_PACKET_LENGTH_ON;
+    bool crcEnabled = false;
 
     bool findChip();
     void clearIrqStatus();