From 14f33c963781daee6e899db6674385d8dd7c17d1 Mon Sep 17 00:00:00 2001
From: fredmcc <mccormackaj@gmail.com>
Date: Sun, 13 Jul 2025 19:15:40 +1000
Subject: [PATCH] Removed potential lock up conditions when sending a packet if
 the TX buffer is full or transmission does not complete

---
 src/ESP32SJA1000.cpp | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/src/ESP32SJA1000.cpp b/src/ESP32SJA1000.cpp
index 309e030..02adb02 100644
--- a/src/ESP32SJA1000.cpp
+++ b/src/ESP32SJA1000.cpp
@@ -168,9 +168,9 @@ int ESP32SJA1000Class::endPacket()
     return 0;
   }
 
-  // wait for TX buffer to free
-  while ((readRegister(REG_SR) & 0x04) != 0x04) {
-    yield();
+  // return if TX buffer is not free
+  if ((readRegister(REG_SR) & 0x04) != 0x04) {
+    return 0;
   }
 
   int dataReg;
@@ -203,15 +203,6 @@ int ESP32SJA1000Class::endPacket()
     modifyRegister(REG_CMR, 0x1f, 0x01);
   }
 
-  // wait for TX complete
-  while ((readRegister(REG_SR) & 0x08) != 0x08) {
-    if (readRegister(REG_ECC) == 0xd9) {
-      modifyRegister(REG_CMR, 0x1f, 0x02); // error, abort
-      return 0;
-    }
-    yield();
-  }
-
   return 1;
 }