init can bus

can_bus.h

@@ -0,0 +1,38 @@
+#include "boards/pico.h"
+#include "hardware/spi.h"
+#include "pico/stdlib.h"
+#include "pico/time.h"
+
+// 16MHz 125Kbps
+#define MCP_CFG1 (0x03)
+#define MCP_CFG2 (0xF0)
+#define MCP_CFG3 (0x86)
+
+typedef struct {
+  spi_inst_t *CHANNEL;
+  uint8_t CS_PIN;
+  // uint8_t TX_PIN;
+  // uint8_t RX_PIN;
+  // uint8_t SCK_PIN;
+  // uint32_t SPI_CLOCK;
+} mcp2515_config;
+
+struct can_frame {
+  uint32_t can_id; // 32 bit CAN_ID + EFF/RTR/ERR flags
+  char can_dlc;    //  frame payload length in byte (0 .. CAN_MAX_DLEN) */
+  char data[8];    // msg
+};
+
+enum MCP_ERROR {
+  ERROR_OK = 0,
+  ERROR_FAIL = 1,
+  ERROR_ALLTXBUSY = 2,
+  ERROR_FAILINIT = 3,
+  ERROR_FAILTX = 4,
+  ERROR_NOMSG = 5
+};
+
+void mcp2515_init(mcp2515_config *config, uint8_t cs_pin, uint8_t tx_pin,
+                  uint8_t rx_pin, uint8_t sck_pin, spi_inst_t *spi_inst);
+enum MCP_ERROR sendMessage(const struct can_frame *frame);
+enum MPC_ERROR readMessage(struct can_frame *frame);