diff --git a/libuavcan_drivers/stm32/driver/include/uavcan_stm32/can.hpp b/libuavcan_drivers/stm32/driver/include/uavcan_stm32/can.hpp
index e9fd446026..2e18e4c615 100644
--- a/libuavcan_drivers/stm32/driver/include/uavcan_stm32/can.hpp
+++ b/libuavcan_drivers/stm32/driver/include/uavcan_stm32/can.hpp
@@ -11,6 +11,19 @@
 
 namespace uavcan_stm32
 {
+/**
+ * Driver error codes.
+ * These values can be returned from driver functions negated.
+ */
+//static const uavcan::int16_t ErrUnknown               = 1000; ///< Reserved for future use
+static const uavcan::int16_t ErrNotImplemented          = 1001; ///< Feature not implemented
+static const uavcan::int16_t ErrInvalidBitRate          = 1002; ///< Bit rate not supported
+static const uavcan::int16_t ErrLogic                   = 1003; ///< Internal logic error
+static const uavcan::int16_t ErrUnsupportedFrame        = 1004; ///< Frame not supported (e.g. RTR, CAN FD, etc)
+static const uavcan::int16_t ErrMsrInakNotSet           = 1005; ///< INAK bit of the MSR register is not 1
+static const uavcan::int16_t ErrMsrInakNotCleared       = 1006; ///< INAK bit of the MSR register is not 0
+static const uavcan::int16_t ErrBitRateNotDetected      = 1007; ///< Auto bit rate detection could not be finished
+
 /**
  * RX queue item.
  * The application shall not use this directly.
@@ -287,7 +300,7 @@ public:
      * This overload simply configures the provided bitrate.
      * Auto bit rate detection will not be performed.
      * Bitrate value must be positive.
-     * @return  Negative value on error; non-negative on success.
+     * @return  Negative value on error; non-negative on success. Refer to constants Err*.
      */
     int init(uavcan::uint32_t bitrate)
     {
@@ -306,7 +319,7 @@ public:
      *                          If auto detection was used, the function will update the argument
      *                          with established bit rate. In case of an error the value will be undefined.
      *
-     * @return                  Negative value on error; non-negative on success.
+     * @return                  Negative value on error; non-negative on success. Refer to constants Err*.
      */
     template <typename DelayCallable>
     int init(DelayCallable delay_callable, uavcan::uint32_t& inout_bitrate = BitRateAutoDetect)
@@ -346,7 +359,7 @@ public:
                 }
             }
 
-            return -1;
+            return -ErrBitRateNotDetected;
         }
     }
 
diff --git a/libuavcan_drivers/stm32/driver/src/uc_stm32_can.cpp b/libuavcan_drivers/stm32/driver/src/uc_stm32_can.cpp
index 5db7288e29..d4de68496f 100644
--- a/libuavcan_drivers/stm32/driver/src/uc_stm32_can.cpp
+++ b/libuavcan_drivers/stm32/driver/src/uc_stm32_can.cpp
@@ -206,7 +206,7 @@ int CanIface::computeTimings(const uavcan::uint32_t target_bitrate, Timings& out
 {
     if (target_bitrate < 1)
     {
-        return -1;
+        return -ErrInvalidBitRate;
     }
 
     /*
@@ -263,7 +263,7 @@ int CanIface::computeTimings(const uavcan::uint32_t target_bitrate, Timings& out
     {
         if (bs1_bs2_sum <= 2)
         {
-            return -1;          // No solution
+            return -ErrInvalidBitRate;          // No solution
         }
         bs1_bs2_sum--;
     }
@@ -271,7 +271,7 @@ int CanIface::computeTimings(const uavcan::uint32_t target_bitrate, Timings& out
     const uavcan::uint32_t prescaler = prescaler_bs / (1 + bs1_bs2_sum);
     if ((prescaler < 1U) || (prescaler > 1024U))
     {
-        return -1;              // No solution
+        return -ErrInvalidBitRate;              // No solution
     }
 
     /*
@@ -334,7 +334,7 @@ int CanIface::computeTimings(const uavcan::uint32_t target_bitrate, Timings& out
     if ((target_bitrate != (pclk / (prescaler * (1 + solution.bs1 + solution.bs2)))) || !solution.isValid())
     {
         UAVCAN_ASSERT(0);
-        return -1;
+        return -ErrLogic;
     }
 
     UAVCAN_STM32_LOG("Timings: quanta/bit: %d, sample point location: %.1f%%",
@@ -352,7 +352,7 @@ uavcan::int16_t CanIface::send(const uavcan::CanFrame& frame, uavcan::MonotonicT
 {
     if (frame.isErrorFrame() || frame.dlc > 8)
     {
-        return -1;  // WTF man how to handle that
+        return -ErrUnsupportedFrame;
     }
 
     /*
@@ -462,7 +462,7 @@ uavcan::int16_t CanIface::configureFilters(const uavcan::CanFilterConfig* filter
     CriticalSectionLocker lock;
     (void)filter_configs;
     (void)num_configs;
-    return -1;
+    return -ErrNotImplemented;
 }
 
 bool CanIface::waitMsrINakBitStateChange(bool target_state)
@@ -503,7 +503,7 @@ int CanIface::init(const uavcan::uint32_t bitrate, const OperatingMode mode)
     if (!waitMsrINakBitStateChange(true))
     {
         UAVCAN_STM32_LOG("MSR INAK not set");
-        return -1;
+        return -ErrMsrInakNotSet;
     }
 
     /*
@@ -551,7 +551,7 @@ int CanIface::init(const uavcan::uint32_t bitrate, const OperatingMode mode)
     if (!waitMsrINakBitStateChange(false))
     {
         UAVCAN_STM32_LOG("MSR INAK not cleared");
-        return -1;
+        return -ErrMsrInakNotCleared;
     }
 
     /*