From bfcd7a4762e407f52e492367ea6dcc1f87c9b168 Mon Sep 17 00:00:00 2001
From: Felix Rusu <felix@lowpowerlab.com>
Date: Fri, 17 Oct 2025 14:07:34 -0400
Subject: [PATCH] Default 433mhz to legal 433.92mhz

Solves #202
---
 RFM69.cpp        | 6 +++---
 RFM69registers.h | 4 ++++
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/RFM69.cpp b/RFM69.cpp
index f27cf52..f3d8a29 100644
--- a/RFM69.cpp
+++ b/RFM69.cpp
@@ -71,9 +71,9 @@ bool RFM69::initialize(uint8_t freqBand, uint16_t nodeID, uint8_t networkID) {
     /* 0x05 */ { REG_FDEVMSB, RF_FDEVMSB_50000}, // default: 5KHz, (FDEV + BitRate / 2 <= 500KHz)
     /* 0x06 */ { REG_FDEVLSB, RF_FDEVLSB_50000},
 
-    /* 0x07 */ { REG_FRFMSB, (uint8_t) (freqBand==RF69_315MHZ ? RF_FRFMSB_315 : (freqBand==RF69_433MHZ ? RF_FRFMSB_433 : (freqBand==RF69_868MHZ ? RF_FRFMSB_868 : RF_FRFMSB_915))) },
-    /* 0x08 */ { REG_FRFMID, (uint8_t) (freqBand==RF69_315MHZ ? RF_FRFMID_315 : (freqBand==RF69_433MHZ ? RF_FRFMID_433 : (freqBand==RF69_868MHZ ? RF_FRFMID_868 : RF_FRFMID_915))) },
-    /* 0x09 */ { REG_FRFLSB, (uint8_t) (freqBand==RF69_315MHZ ? RF_FRFLSB_315 : (freqBand==RF69_433MHZ ? RF_FRFLSB_433 : (freqBand==RF69_868MHZ ? RF_FRFLSB_868 : RF_FRFLSB_915))) },
+    /* 0x07 */ { REG_FRFMSB, (uint8_t) (freqBand==RF69_315MHZ ? RF_FRFMSB_315 : (freqBand==RF69_433MHZ ? RF_FRFMSB_433_92 : (freqBand==RF69_868MHZ ? RF_FRFMSB_868 : RF_FRFMSB_915))) },
+    /* 0x08 */ { REG_FRFMID, (uint8_t) (freqBand==RF69_315MHZ ? RF_FRFMID_315 : (freqBand==RF69_433MHZ ? RF_FRFMID_433_92 : (freqBand==RF69_868MHZ ? RF_FRFMID_868 : RF_FRFMID_915))) },
+    /* 0x09 */ { REG_FRFLSB, (uint8_t) (freqBand==RF69_315MHZ ? RF_FRFLSB_315 : (freqBand==RF69_433MHZ ? RF_FRFLSB_433_92 : (freqBand==RF69_868MHZ ? RF_FRFLSB_868 : RF_FRFLSB_915))) },
 
     // looks like PA1 and PA2 are not implemented on RFM69W/CW, hence the max output power is 13dBm
     // +17dBm and +20dBm are possible on RFM69HW
diff --git a/RFM69registers.h b/RFM69registers.h
index b02fbbb..dc26567 100644
--- a/RFM69registers.h
+++ b/RFM69registers.h
@@ -305,6 +305,10 @@
 #define RF_FRFMSB_433             0x6C
 #define RF_FRFMID_433             0x40
 #define RF_FRFLSB_433             0x00
+//center frequency: 433.92 - see https://github.com/LowPowerLab/RFM69/issues/202
+#define RF_FRFMSB_433_92          0x6C
+#define RF_FRFMID_433_92          0x7A
+#define RF_FRFLSB_433_92          0xE1
 #define RF_FRFMSB_434             0x6C
 #define RF_FRFMID_434             0x80
 #define RF_FRFLSB_434             0x00