From 60ccd852e34f08c13f70c1339ba6606128c14460 Mon Sep 17 00:00:00 2001
From: Raphael Coeffic <raphaelcoeffic@users.noreply.github.com>
Date: Sat, 23 Sep 2023 06:45:15 +0200
Subject: [PATCH] fix: Prevent enabling USART IRQ if not supported (#4086)

Fixes #4073
---
 radio/src/targets/common/arm/stm32/stm32_usart_driver.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/radio/src/targets/common/arm/stm32/stm32_usart_driver.cpp b/radio/src/targets/common/arm/stm32/stm32_usart_driver.cpp
index c046f129c..71f513004 100644
--- a/radio/src/targets/common/arm/stm32/stm32_usart_driver.cpp
+++ b/radio/src/targets/common/arm/stm32/stm32_usart_driver.cpp
@@ -289,7 +289,9 @@ void stm32_usart_init(const stm32_usart_t* usart, const etx_serial_init* params)
 
   if (params->direction & ETX_Dir_RX) {
     // IRQ based RX
-    LL_USART_EnableIT_RXNE(usart->USARTx);
+    if ((int32_t)(usart->IRQn) >= 0) {
+      LL_USART_EnableIT_RXNE(usart->USARTx);
+    }
 
     // half-duplex: start in input mode
     if (usart->set_input)