From 86dfdfff895d0403f5d2259920dcca795fb1ebe9 Mon Sep 17 00:00:00 2001
From: dxl <64101226@qq.com>
Date: Thu, 20 Aug 2026 00:34:16 +0800
Subject: [PATCH] Fixed a bug in reading hitagU and hitagS on RDV4.

---
 common_arm/ticks/ticks_hw_at91.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/common_arm/ticks/ticks_hw_at91.c b/common_arm/ticks/ticks_hw_at91.c
index b1c186aa3..987bc95fd 100644
--- a/common_arm/ticks/ticks_hw_at91.c
+++ b/common_arm/ticks/ticks_hw_at91.c
@@ -272,10 +272,12 @@ uint16_t RAMFUNC GetLoEdgeCaptureCount(void) {
 }
 
 lo_edge_t RAMFUNC GetLoEdgeCaptureStatus(void) {
-    if (AT91C_BASE_TC1->TC_SR & INPUT_CAPTURE_EVT_RISING_EDGE) {
+    // Read Once Only: Reading TC_SR will simultaneously clear status bits such as LDRAS/LDRBS.
+    uint32_t sr = AT91C_BASE_TC1->TC_SR;
+    if (sr & INPUT_CAPTURE_EVT_RISING_EDGE) {
         return LO_EDGE_RISING;
     }
-    if (AT91C_BASE_TC1->TC_SR & INPUT_CAPTURE_EVT_FALLING_EDGE) {
+    if (sr & INPUT_CAPTURE_EVT_FALLING_EDGE) {
         return LO_EDGE_FALLING;
     }
     return LO_EDGE_NO;