diff --git a/libraries/AP_CANManager/AP_CANDriver.h b/libraries/AP_CANManager/AP_CANDriver.h
index f93e96cec0e7a..5f1c4f74a2a76 100644
--- a/libraries/AP_CANManager/AP_CANDriver.h
+++ b/libraries/AP_CANManager/AP_CANDriver.h
@@ -40,5 +40,5 @@ class AP_CANDriver
     virtual bool add_11bit_driver(CANSensor *sensor) { return false; }
 
     // handler for outgoing frames for auxillary drivers
-    virtual bool write_aux_frame(AP_HAL::CANFrame &out_frame, const uint64_t timeout_us) { return false; }
+    virtual bool write_aux_frame(AP_HAL::CANFrame &out_frame, const uint32_t timeout_us) { return false; }
 };
diff --git a/libraries/AP_CANManager/AP_CANSensor.cpp b/libraries/AP_CANManager/AP_CANSensor.cpp
index e86ef31992475..ffa9bf3cc6d9f 100644
--- a/libraries/AP_CANManager/AP_CANSensor.cpp
+++ b/libraries/AP_CANManager/AP_CANSensor.cpp
@@ -135,7 +135,7 @@ bool CANSensor::add_interface(AP_HAL::CANIface* can_iface)
     return true;
 }
 
-bool CANSensor::write_frame(AP_HAL::CANFrame &out_frame, const uint64_t timeout_us)
+bool CANSensor::write_frame(AP_HAL::CANFrame &out_frame, const uint32_t timeout_us)
 {
     if (!_initialized) {
         debug_can(AP_CANManager::LOG_ERROR, "Driver not initialized for write_frame");
@@ -171,12 +171,12 @@ void CANSensor::loop()
 #endif
 
     while (true) {
-        uint64_t timeout = AP_HAL::micros64() + LOOP_INTERVAL_US;
+        uint64_t deadline_us = AP_HAL::micros64() + LOOP_INTERVAL_US;
 
         // wait to receive frame
         bool read_select = true;
         bool write_select = false;
-        bool ret = _can_iface->select(read_select, write_select, nullptr, timeout);
+        bool ret = _can_iface->select(read_select, write_select, nullptr, deadline_us);
         if (ret && read_select) {
             uint64_t time;
             AP_HAL::CANIface::CanIOFlags flags {};
diff --git a/libraries/AP_CANManager/AP_CANSensor.h b/libraries/AP_CANManager/AP_CANSensor.h
index 7afd1bbea0fa5..b5ac4ee3b0b0f 100644
--- a/libraries/AP_CANManager/AP_CANSensor.h
+++ b/libraries/AP_CANManager/AP_CANSensor.h
@@ -43,7 +43,7 @@ class CANSensor : public AP_CANDriver {
     virtual void handle_frame(AP_HAL::CANFrame &frame) = 0;
 
     // handler for outgoing frames
-    bool write_frame(AP_HAL::CANFrame &out_frame, const uint64_t timeout_us);
+    bool write_frame(AP_HAL::CANFrame &out_frame, const uint32_t timeout_us);
 
 #ifdef HAL_BUILD_AP_PERIPH
     static void set_periph(const uint8_t i, const AP_CAN::Protocol protocol, AP_HAL::CANIface* iface) {
diff --git a/libraries/AP_DroneCAN/AP_Canard_iface.cpp b/libraries/AP_DroneCAN/AP_Canard_iface.cpp
index 7382f57033c9d..fd38e303c4253 100644
--- a/libraries/AP_DroneCAN/AP_Canard_iface.cpp
+++ b/libraries/AP_DroneCAN/AP_Canard_iface.cpp
@@ -456,7 +456,7 @@ bool CanardInterface::add_11bit_driver(CANSensor *sensor)
 }
 
 // handler for outgoing frames for auxillary drivers
-bool CanardInterface::write_aux_frame(AP_HAL::CANFrame &out_frame, const uint64_t timeout_us)
+bool CanardInterface::write_aux_frame(AP_HAL::CANFrame &out_frame, const uint32_t timeout_us)
 {
     const uint64_t tx_deadline_us = AP_HAL::micros64() + timeout_us;
     bool ret = false;
diff --git a/libraries/AP_DroneCAN/AP_Canard_iface.h b/libraries/AP_DroneCAN/AP_Canard_iface.h
index 43d786639fdf0..671722028dffc 100644
--- a/libraries/AP_DroneCAN/AP_Canard_iface.h
+++ b/libraries/AP_DroneCAN/AP_Canard_iface.h
@@ -54,7 +54,7 @@ class CanardInterface : public Canard::Interface {
     bool add_11bit_driver(CANSensor *sensor);
 
     // handler for outgoing frames for auxillary drivers
-    bool write_aux_frame(AP_HAL::CANFrame &out_frame, const uint64_t timeout_us);
+    bool write_aux_frame(AP_HAL::CANFrame &out_frame, const uint32_t timeout_us);
     
 #if AP_TEST_DRONECAN_DRIVERS
     static CanardInterface& get_test_iface() { return test_iface; }
diff --git a/libraries/AP_DroneCAN/AP_DroneCAN.cpp b/libraries/AP_DroneCAN/AP_DroneCAN.cpp
index 21243e5d08c40..639e017e82cb6 100644
--- a/libraries/AP_DroneCAN/AP_DroneCAN.cpp
+++ b/libraries/AP_DroneCAN/AP_DroneCAN.cpp
@@ -1956,7 +1956,7 @@ bool AP_DroneCAN::add_11bit_driver(CANSensor *sensor)
 }
 
 // handler for outgoing frames for auxillary drivers
-bool AP_DroneCAN::write_aux_frame(AP_HAL::CANFrame &out_frame, const uint64_t timeout_us)
+bool AP_DroneCAN::write_aux_frame(AP_HAL::CANFrame &out_frame, const uint32_t timeout_us)
 {
     if (out_frame.isExtended()) {
         // don't allow extended frames to be sent by auxillary driver
diff --git a/libraries/AP_DroneCAN/AP_DroneCAN.h b/libraries/AP_DroneCAN/AP_DroneCAN.h
index 2d6e5ae2b7f78..9a7ae54c6639c 100644
--- a/libraries/AP_DroneCAN/AP_DroneCAN.h
+++ b/libraries/AP_DroneCAN/AP_DroneCAN.h
@@ -95,7 +95,7 @@ class AP_DroneCAN : public AP_CANDriver, public AP_ESC_Telem_Backend {
     bool add_11bit_driver(CANSensor *sensor) override;
 
     // handler for outgoing frames for auxillary drivers
-    bool write_aux_frame(AP_HAL::CANFrame &out_frame, const uint64_t timeout_us) override;
+    bool write_aux_frame(AP_HAL::CANFrame &out_frame, const uint32_t timeout_us) override;
     
     uint8_t get_driver_index() const { return _driver_index; }