From 38ffacf80ed068f858a1054a4e1f7d1187679af3 Mon Sep 17 00:00:00 2001
From: Dominic Clifton <dominic.clifton@cleanflight.com>
Date: Tue, 24 Dec 2019 21:05:02 +0100
Subject: [PATCH] Prevent EXTI handler from crashing when EXTI lines 16-32 are
 used.

Refer to "EXTI Event Input mapping" table in MCU reference manuals.
---
 src/main/drivers/exti.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/main/drivers/exti.c b/src/main/drivers/exti.c
index a1726dc912..4e520ab0e1 100644
--- a/src/main/drivers/exti.c
+++ b/src/main/drivers/exti.c
@@ -229,9 +229,11 @@ void EXTIEnable(IO_t io, bool enable)
 #endif
 }
 
+#define EXTI_EVENT_MASK 0xFFFF // first 16 bits only, see also definition of extiChannelRecs.
+
 void EXTI_IRQHandler(void)
 {
-    uint32_t exti_active = EXTI_REG_IMR & EXTI_REG_PR;
+    uint32_t exti_active = (EXTI_REG_IMR & EXTI_REG_PR) & EXTI_EVENT_MASK;
 
     while (exti_active) {
         unsigned idx = 31 - __builtin_clz(exti_active);