Trouble reading Motec ECU Can messages #12097
Description
Board
ESP32 s2 mini
Device Description
ESP32-S2-mini <-> CJMCU230 transceiver <-> Motec ECU <-> Motec USB to CAN module
Hardware Configuration
CAN H and CAN L connected to CJMCU230
CJMCU and ESP32 S2 mini as below :
RX_PIN <-> GPIO6
TX_PIN <-> GPIO7
GND <-> GND
3V3 <-> 3V3
Version
latest stable Release (if not listed below)
Type
Question
IDE Name
Arduino IDE
Operating System
Windows 11
Flash frequency
NC
PSRAM enabled
yes
Upload speed
NC
Description
Hello,
I'm trying to use esp32 and CJMCU-230 can transceiver to read data from a Motec car ECU
the ECU is connected to Motec USB to CAN module and to CJMCU-230 through RX and TX lines.
I'm using twisted pairs, the bus is around 50cm long and each device has a termination resistor
Everything works ok with the "TWAI receive" sketch below.
But sometimes, i have CAN bus errors (coming from Spark coil EMI, whereas my setup is in a metal box connected to ESP32 ground)
When those errors occurs, i have the following message in the Serial console, then nothing more :
....
Message is in Standard Format
ID: e8
Byte: 0 = 00, 1 = 02, 2 = 00, 3 = 00, 4 = 00, 5 = 00, 6 = 00, 7 = 00,
Alert: The RX queue is full causing a received frame to be lost.
RX buffered: 0 RX missed: 594651 RX overrun 0
For recovering CAN BUS reading, i have to POWER OFF then ON my Motec ECU.
The weird thing is that the CANBUS to USB module continues to receive data without the need of this restart (but maybe it works on another CAN channel).
How can i recover my program without restarting ECU please ?
And maybe someone have advices to avoid CAN errors ?
Sorry for my poor English
Thanks
Sketch
ESP32 TWAI receive example.
Receive messages and sends them over serial.
Connect a CAN bus transceiver to the RX/TX pins.
For example: SN65HVD230
TWAI_MODE_LISTEN_ONLY is used so that the TWAI controller will not influence the bus.
The API gives other possible speeds and alerts:
https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-reference/peripherals/twai.html
Example output from a can bus message:
-> Message received
-> Message is in Standard Format
-> ID: 604
-> Byte: 0 = 00, 1 = 0f, 2 = 13, 3 = 02, 4 = 00, 5 = 00, 6 = 08, 7 = 00
Example output with alerts:
-> Alert: A (Bit, Stuff, CRC, Form, ACK) error has occurred on the bus.
-> Bus error count: 171
-> Alert: The RX queue is full causing a received frame to be lost.
-> RX buffered: 4 RX missed: 46 RX overrun 0
created 05-11-2022 by Stephan Martin (designer2k2)
*/
#pragma GCC diagnostic ignored "-Wmissing-field-initializers"
#include "driver/twai.h"
// Pins used to connect to CAN bus transceiver:
#define RX_PIN 6
#define TX_PIN 7
// Interval:
#define POLLING_RATE_MS 1000
static bool driver_installed = false;
void setup() {
// Start Serial:
Serial.begin(500000);
//Serial.setTxTimeoutMs(0);
// Initialize configuration structures using macro initializers
twai_general_config_t g_config = TWAI_GENERAL_CONFIG_DEFAULT((gpio_num_t)TX_PIN, (gpio_num_t)RX_PIN, TWAI_MODE_NORMAL);
twai_timing_config_t t_config = TWAI_TIMING_CONFIG_1MBITS(); //Look in the api-reference for other speed sets.
twai_filter_config_t f_config = { .acceptance_code = (0xE8 << 21),
.acceptance_mask = ~(0x7FF << 21),
.single_filter = true };
//twai_filter_config_t f_config = TWAI_FILTER_CONFIG_ACCEPT_ALL();
// Install TWAI driver
if (twai_driver_install(&g_config, &t_config, &f_config) == ESP_OK) {
Serial.println("Driver installed");
} else {
Serial.println("Failed to install driver");
return;
}
// Start TWAI driver
if (twai_start() == ESP_OK) {
Serial.println("Driver started");
} else {
Serial.println("Failed to start driver");
return;
}
// Reconfigure alerts to detect frame receive, Bus-Off error and RX queue full states
uint32_t alerts_to_enable = TWAI_ALERT_RX_DATA | TWAI_ALERT_ERR_PASS | TWAI_ALERT_BUS_ERROR | TWAI_ALERT_RX_QUEUE_FULL;
if (twai_reconfigure_alerts(alerts_to_enable, NULL) == ESP_OK) {
Serial.println("CAN Alerts reconfigured");
} else {
Serial.println("Failed to reconfigure alerts");
return;
}
// TWAI driver is now successfully installed and started
driver_installed = true;
}
static void handle_rx_message(twai_message_t &message) {
// Process received message
if (message.extd) {
Serial.println("Message is in Extended Format");
} else {
Serial.println("Message is in Standard Format");
}
Serial.printf("ID: %lx\nByte:", message.identifier);
if (!(message.rtr)) {
for (int i = 0; i < message.data_length_code; i++) {
Serial.printf(" %d = %02x,", i, message.data[i]);
}
Serial.println("");
}
}
void loop() {
if (!driver_installed) {
// Driver not installed
Serial.println("Failed to install driver");
delay(1000);
return;
}
// Check if alert happened
uint32_t alerts_triggered;
twai_read_alerts(&alerts_triggered, pdMS_TO_TICKS(POLLING_RATE_MS));
twai_status_info_t twaistatus;
twai_get_status_info(&twaistatus);
// Handle alerts
if (alerts_triggered & TWAI_ALERT_ERR_PASS) {
Serial.println("Alert: TWAI controller has become error passive.");
}
if (alerts_triggered & TWAI_ALERT_BUS_ERROR) {
Serial.println("Alert: A (Bit, Stuff, CRC, Form, ACK) error has occurred on the bus.");
Serial.printf("Bus error count: %lu\n", twaistatus.bus_error_count);
}
if (alerts_triggered & TWAI_ALERT_RX_QUEUE_FULL) {
Serial.println("Alert: The RX queue is full causing a received frame to be lost.");
Serial.printf("RX buffered: %lu\t", twaistatus.msgs_to_rx);
Serial.printf("RX missed: %lu\t", twaistatus.rx_missed_count);
Serial.printf("RX overrun %lu\n", twaistatus.rx_overrun_count);
}
// Check if message is received
if (alerts_triggered & TWAI_ALERT_RX_DATA) {
// One or more messages received. Handle all.
twai_message_t message;
while (twai_receive(&message, 0) == ESP_OK) {
handle_rx_message(message);
}
}
}Debug Message
....
Message is in Standard Format
ID: e8
Byte: 0 = 00, 1 = 02, 2 = 00, 3 = 00, 4 = 00, 5 = 00, 6 = 00, 7 = 00,
Alert: The RX queue is full causing a received frame to be lost.
RX buffered: 0 RX missed: 594651 RX overrun 0
Other Steps to Reproduce
No response
I have checked existing issues, online documentation and the Troubleshooting Guide
- I confirm I have checked existing issues, online documentation and Troubleshooting guide.