diff --git a/mcp2515.h b/mcp2515.h
index 604cc52..6398196 100644
--- a/mcp2515.h
+++ b/mcp2515.h
@@ -56,6 +56,12 @@ typedef struct {
     uint16_t cs_pin;
 } MCP2515_HandleTypeDef;
 
+typedef struct can_frame_s {
+    uint32_t can_id;  /* 32 bit CAN_ID + EFF/RTR/ERR flags */
+    uint8_t  can_dlc;
+    uint8_t  data[8];
+} can_frame_t;
+
 void MCP2515_Init(MCP2515_HandleTypeDef* hcan, SPI_HandleTypeDef* hspi, GPIO_TypeDef* cs_port, uint16_t cs_pin);
 CAN_Error MCP2515_Reset(MCP2515_HandleTypeDef* hcan);
 uint8_t MCP2515_Get_Status(MCP2515_HandleTypeDef* hcan);
diff --git a/mcp2515_consts.h b/mcp2515_consts.h
index 018761d..4d06fc4 100644
--- a/mcp2515_consts.h
+++ b/mcp2515_consts.h
@@ -4,6 +4,32 @@
 
 #include <stdint.h>
 
+/* special address description flags for the CAN_ID */
+#define CAN_EFF_FLAG 0x80000000UL /* EFF/SFF is set in the MSB */
+#define CAN_RTR_FLAG 0x40000000UL /* remote transmission request */
+#define CAN_ERR_FLAG 0x20000000UL /* error message frame */
+
+/* valid bits in CAN ID for frame formats */
+#define CAN_SFF_MASK 0x000007FFUL /* standard frame format (SFF) */
+#define CAN_EFF_MASK 0x1FFFFFFFUL /* extended frame format (EFF) */
+#define CAN_ERR_MASK 0x1FFFFFFFUL /* omit EFF, RTR, ERR flags */
+
+/*
+ * Controller Area Network Identifier structure
+ *
+ * bit 0-28 : CAN identifier (11/29 bit)
+ * bit 29   : error message frame flag (0 = data frame, 1 = error message)
+ * bit 30   : remote transmission request flag (1 = rtr frame)
+ * bit 31   : frame format flag (0 = standard 11 bit, 1 = extended 29 bit)
+ */
+
+#define CAN_SFF_ID_BITS     11
+#define CAN_EFF_ID_BITS     29
+
+/* CAN payload length and DLC definitions according to ISO 11898-1 */
+#define CAN_MAX_DLC 8
+#define CAN_MAX_DLEN 8
+
 /*
  *  Speed 8M
  */