From fb60d6f7fd6e5e7ec788cbc0f4df6a29bbb436a0 Mon Sep 17 00:00:00 2001
From: Armel FAUVEAU <armel.fauveau@globalis-ms.com>
Date: Thu, 9 Apr 2026 02:44:20 +0200
Subject: [PATCH] Add WIDE/NARROW filter selection for AM RX

---
 App/app/action.c |  2 +-
 App/radio.c      | 10 ++++++++--
 App/radio.h      |  2 ++
 3 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/App/app/action.c b/App/app/action.c
index b621cf6f..560f278f 100644
--- a/App/app/action.c
+++ b/App/app/action.c
@@ -597,7 +597,7 @@ void ACTION_Wn(void)
 
     if (pVfo->Modulation == MODULATION_AM)
     {
-        BK4819_SetFilterBandwidth(BK4819_FILTER_BW_AM, true);
+        BK4819_SetFilterBandwidth(RADIO_GetAMFilterBandwidth(pVfo), true);
         return;
     }
 
diff --git a/App/radio.c b/App/radio.c
index 31556821..a1cc845e 100644
--- a/App/radio.c
+++ b/App/radio.c
@@ -771,6 +771,12 @@ void RADIO_SelectVfos(void)
     RADIO_SelectCurrentVfo();
 }
 
+BK4819_FilterBandwidth_t RADIO_GetAMFilterBandwidth(const VFO_Info_t *pVfo)
+{
+    // On BK4829, AM "wide" intentionally reuses the wider RF filter preset.
+    return (pVfo->CHANNEL_BANDWIDTH == BANDWIDTH_WIDE) ? BK4819_FILTER_BW_WIDE : BK4819_FILTER_BW_AM;
+}
+
 void RADIO_SetupRegisters(bool switchToForeground)
 {
     BK4819_FilterBandwidth_t Bandwidth = gRxVfo->CHANNEL_BANDWIDTH;
@@ -789,7 +795,7 @@ void RADIO_SetupRegisters(bool switchToForeground)
     BK4819_ToggleGpioOut(BK4819_GPIO6_PIN2_GREEN, false);
 
     if (gRxVfo->Modulation == MODULATION_AM)
-        BK4819_SetFilterBandwidth(BK4819_FILTER_BW_AM, true);
+        BK4819_SetFilterBandwidth(RADIO_GetAMFilterBandwidth(gRxVfo), true);
     else
     {
         switch (Bandwidth)
@@ -1153,7 +1159,7 @@ void RADIO_SetModulation(ModulationMode_t modulation)
                 BK4819_WriteRegister(0x55, 0x31a9);
             #endif
 
-            BK4819_SetFilterBandwidth(BK4819_FILTER_BW_AM, true);
+            BK4819_SetFilterBandwidth(RADIO_GetAMFilterBandwidth(gCurrentVfo), true);
             break;
         }
 
diff --git a/App/radio.h b/App/radio.h
index ee2c0efd..8fa28fa3 100644
--- a/App/radio.h
+++ b/App/radio.h
@@ -21,6 +21,7 @@
 #include <stdint.h>
 
 #include "dcs.h"
+#include "driver/bk4819.h"
 #include "frequencies.h"
 
 enum {
@@ -161,6 +162,7 @@ void     RADIO_SetupRegisters(bool switchToForeground);
 #ifdef ENABLE_NOAA
     void RADIO_ConfigureNOAA(void);
 #endif
+BK4819_FilterBandwidth_t RADIO_GetAMFilterBandwidth(const VFO_Info_t *pVfo);
 void     RADIO_SetTxParameters(void);
 void     RADIO_SetupAGC(bool listeningAM, bool disable);
 void     RADIO_SetModulation(ModulationMode_t modulation);