Getting started with an IVT-S and Arduino Uno CAN bus shield

First of all, set up your Arduino Uno and CAN bus shield.

Once the data is coming in over CAN, we can write a simple program to read the current value from the IVT-S

Here's the code:

// IVT-S meter using CAN-BUS Shield // electric_dart 2020 #include <SPI.h> #include "mcp_can.h" /*SAMD core*/ #ifdef ARDUINO_SAMD_VARIANT_COMPLIANCE #define SERIAL SerialUSB #else #define SERIAL Serial #endif // the cs pin of the version after v1.1 is default to D9 // v0.9b and v1.0 is default D10 const int SPI_CS_PIN = 10; const int CAN_INT_PIN = 2; MCP_CAN CAN(SPI_CS_PIN); // Set CS pin unsigned char flagRecv = 0; unsigned char len = 0; unsigned char buf[8]; char str[20]; void setup() { SERIAL.begin(115200); while (!SERIAL) {  ; // wait for serial port to connect. Needed for native USB port only } while (CAN_OK != CAN.begin(CAN_1000KBPS)) { // init can bus SERIAL.println("CAN BUS Shield init fail"); SERIAL.println("Init CAN BUS Shield again"); delay(100); } SERIAL.println("CAN BUS Shield init ok!"); attachInterrupt(digitalPinToInterrupt(CAN_INT_PIN), MCP2515_ISR, FALLING); // start interrupt /* set receive mask */ CAN.init_Mask(0, 0, 0x7ff); // there are 2 masks in mcp2515, you need to set both of them CAN.init_Mask(1, 0, 0x7ff); // 0x7ff is '11111111111' in binary, so we are checking 11 of the CAN message ID bits /* set receive filter */ CAN.init_Filt(0, 0, 0x521); // there are 6 filters in mcp2515 CAN.init_Filt(1, 0, 0x521); // 0x521 is the CAN mssage ID for IVT-S Current value CAN.init_Filt(2, 0, 0x521); CAN.init_Filt(3, 0, 0x521); CAN.init_Filt(4, 0, 0x521); CAN.init_Filt(5, 0, 0x521); } void MCP2515_ISR() { flagRecv = 1; } void loop() { if (flagRecv) { // check if get data flagRecv = 0; // clear flag // iterate over all pending messages // If either the bus is saturated or the MCU is busy, // both RX buffers may be in use and reading a single // message does not clear the IRQ conditon. while (CAN_MSGAVAIL == CAN.checkReceive()) { // read data, len: data length, buf: data buf CAN.readMsgBuf(&len, buf); unsigned long canId = CAN.getCanId(); if (canId == 0x521) { SERIAL.print("Data received from IVT_Msg_Result_I"); SERIAL.print("\t"); // Convert individual big endian byte values to actual reading long reading = (buf[2] << 24) | (buf[3] << 16) | (buf[4] << 8) | (buf[5]); SERIAL.print(reading); } SERIAL.println(); } } }