From a2cece4d41ce8a03e32e401a18fe5cae09bfa7c0 Mon Sep 17 00:00:00 2001
From: Arduino Enigma <arduinoenigma@gmail.com>
Date: Sun, 6 Jul 2025 13:11:30 -0400
Subject: [PATCH 1/2] Update mcp2515.h

added One Shot Mode flag and enable / disable methods
---
 mcp2515.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/mcp2515.h b/mcp2515.h
index 48e5d57..a9374c8 100644
--- a/mcp2515.h
+++ b/mcp2515.h
@@ -449,6 +449,7 @@ class MCP2515
         uint8_t SPICS;
         uint32_t SPI_CLOCK;
         SPIClass * SPIn;
+        bool OSMflag;
 
     private:
 
@@ -496,6 +497,8 @@ class MCP2515
         void clearERRIF();
         uint8_t errorCountRX(void);
         uint8_t errorCountTX(void);
+        void enableOSM(void);
+        void disableOSM(void);
 };
 
 #endif

From e1c517fc210cc3b8daf816e0c0ae7a1ef2c7141c Mon Sep 17 00:00:00 2001
From: Arduino Enigma <arduinoenigma@gmail.com>
Date: Sun, 6 Jul 2025 13:21:49 -0400
Subject: [PATCH 2/2] added One Shot Mode support

---
 mcp2515.cpp | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/mcp2515.cpp b/mcp2515.cpp
index b942b55..648b0f2 100644
--- a/mcp2515.cpp
+++ b/mcp2515.cpp
@@ -26,6 +26,7 @@ MCP2515::MCP2515(const uint8_t _CS, const uint32_t _SPI_CLOCK, SPIClass * _SPI)
     SPI_CLOCK = _SPI_CLOCK;
     pinMode(SPICS, OUTPUT);
     digitalWrite(SPICS, HIGH);
+    OSMflag = false;
 }
 
 void MCP2515::startSPI() {
@@ -179,7 +180,7 @@ MCP2515::ERROR MCP2515::setNormalMode()
 
 MCP2515::ERROR MCP2515::setMode(const CANCTRL_REQOP_MODE mode)
 {
-    modifyRegister(MCP_CANCTRL, CANCTRL_REQOP, mode);
+    modifyRegister(MCP_CANCTRL, CANCTRL_REQOP | CANCTRL_OSM, OSMflag ? mode | CANCTRL_OSM : mode & ~(CANCTRL_OSM));
 
     unsigned long endTime = millis() + 10;
     bool modeMatch = false;
@@ -777,3 +778,13 @@ uint8_t MCP2515::errorCountTX(void)
 {
     return readRegister(MCP_TEC);
 }
+
+// these merely set the OSM flag
+// setMode(...) or the other setXxxxMode() i.e: setNormalMode() must be called afterwards to set the correct mode with OSM
+void MCP2515::enableOSM(void) {
+    OSMflag = true;
+}
+
+void MCP2515::disableOSM(void) {
+    OSMflag = false;
+}