From 7fcdfe5b5c795da19d7d8db03eacf7d4a811d709 Mon Sep 17 00:00:00 2001
From: 3djc <5167938+3djc@users.noreply.github.com>
Date: Mon, 16 Feb 2026 09:39:13 +0100
Subject: [PATCH] feat(radio): bluetooth audio KCX mod support for TX16S MK3
 (#7056)

---
 radio/src/boards/rm-h750/audio_driver.cpp |  2 +-
 radio/src/drivers/kcx_btaudio.cpp         |  6 +++++-
 radio/src/targets/tx16smk3/CMakeLists.txt | 15 +++++++++++++--
 radio/src/targets/tx16smk3/hal.h          |  6 ++++++
 4 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/radio/src/boards/rm-h750/audio_driver.cpp b/radio/src/boards/rm-h750/audio_driver.cpp
index ee83c1fc8..732288da7 100644
--- a/radio/src/boards/rm-h750/audio_driver.cpp
+++ b/radio/src/boards/rm-h750/audio_driver.cpp
@@ -163,7 +163,7 @@ static void audio_update_dma_buffer(uint8_t tc)
 bool audioHeadphoneDetect()
 {
 #if defined(KCX_BTAUDIO)
-  return gpio_read(AUDIO_HP_DETECT_PIN) || gpio_read(BTAUDIO_LINKED_GPIO);
+  return gpio_read(AUDIO_HP_DETECT_PIN) || btAudioLinked();
 #else
   return gpio_read(AUDIO_HP_DETECT_PIN);
 #endif
diff --git a/radio/src/drivers/kcx_btaudio.cpp b/radio/src/drivers/kcx_btaudio.cpp
index 4c2dc3075..e848bfe56 100644
--- a/radio/src/drivers/kcx_btaudio.cpp
+++ b/radio/src/drivers/kcx_btaudio.cpp
@@ -26,6 +26,10 @@
 
 void btAudioInit()
 {
+#if defined(BTAUDIO_POWER_GPIO)
+  gpio_init(BTAUDIO_POWER_GPIO, GPIO_OUT, GPIO_PIN_SPEED_LOW);
+  gpio_set(BTAUDIO_POWER_GPIO);
+#endif
   gpio_init(BTAUDIO_LINKED_GPIO, GPIO_IN, GPIO_PIN_SPEED_LOW);
   gpio_init(BTAUDIO_CONNECT_GPIO, GPIO_OUT, GPIO_PIN_SPEED_LOW);
   gpio_set(BTAUDIO_CONNECT_GPIO);
@@ -33,7 +37,7 @@ void btAudioInit()
 
 bool btAudioLinked()
 {
-  return gpio_read(BTAUDIO_LINKED_GPIO);
+  return gpio_read(BTAUDIO_LINKED_GPIO) != 0;
 }
 
 void btAudioConnect()
diff --git a/radio/src/targets/tx16smk3/CMakeLists.txt b/radio/src/targets/tx16smk3/CMakeLists.txt
index 61080fc12..8c3e21442 100644
--- a/radio/src/targets/tx16smk3/CMakeLists.txt
+++ b/radio/src/targets/tx16smk3/CMakeLists.txt
@@ -8,6 +8,7 @@ option(MODULE_SIZE_STD "Standard size TX Module" ON)
 option(LUA_MIXER "Enable LUA mixer/model scripts support" ON)
 option(DISK_CACHE "Enable SD card disk cache" ON)
 option(INTERNAL_GPS "Support for internal GPS" ON)
+option(KCX_BTAUDIO "KCX_BTAUDIO audio emitter installed" OFF)
 
 set(FIRMWARE_QSPI YES)
 set(FIRMWARE_FORMAT_UF2 YES)
@@ -71,8 +72,11 @@ set(SOFTWARE_KEYBOARD ON)
 set(FUNCTION_SWITCHES ON)
 set(USB_CHARGER YES)
 set(AUX_SERIAL YES)
-set(AUX2_SERIAL YES)
-
+if(KCX_BTAUDIO)
+  set(AUX2_SERIAL NO)
+else()
+  set(AUX2_SERIAL YES)
+endif()
 add_definitions(
   -DSTM32H750XBTx -DSTM32H750xx
   -DSDRAM -DCCMRAM
@@ -208,5 +212,12 @@ if (MULTIMODULE)
     )
 endif()
 
+if(KCX_BTAUDIO)
+  set(SRC ${SRC}
+    drivers/kcx_btaudio.cpp
+  )
+  add_definitions(-DKCX_BTAUDIO)
+endif()
+
 # Make malloc() thread-safe
 add_definitions(-DTHREADSAFE_MALLOC)
diff --git a/radio/src/targets/tx16smk3/hal.h b/radio/src/targets/tx16smk3/hal.h
index 9f0797d3e..0178280a0 100644
--- a/radio/src/targets/tx16smk3/hal.h
+++ b/radio/src/targets/tx16smk3/hal.h
@@ -541,6 +541,7 @@ USART6: INTMODULE_USART
 #define AUX_SERIAL_DMA_RX_CHANNEL           LL_DMAMUX1_REQ_UART5_RX
 #define AUX_SERIAL_PWR_GPIO                 GPIO_PIN(GPIOB, 7) // PB.07
 
+#if defined(AUX2_SERIAL)
 #define AUX2_SERIAL_TX_GPIO                 GPIO_PIN(GPIOB, 10) // PB.10
 #define AUX2_SERIAL_RX_GPIO                 GPIO_PIN(GPIOB, 11) // PB.11
 #define AUX2_SERIAL_USART                   USART3
@@ -553,6 +554,11 @@ USART6: INTMODULE_USART
 #define AUX2_SERIAL_DMA_RX_STREAM           LL_DMA_STREAM_6
 #define AUX2_SERIAL_DMA_RX_CHANNEL          LL_DMAMUX1_REQ_USART3_RX
 #define AUX2_SERIAL_PWR_GPIO                GPIO_PIN(GPIOC, 13) // PC.13
+#elif defined(KCX_BTAUDIO)
+#define BTAUDIO_POWER_GPIO                  GPIO_PIN(GPIOC, 13)
+#define BTAUDIO_LINKED_GPIO                 GPIO_PIN(GPIOB, 11)
+#define BTAUDIO_CONNECT_GPIO                GPIO_PIN(GPIOB, 10)
+#endif
 
 // Touch
 #define TOUCH_I2C_BUS                   I2C_Bus_1