The current demo code from git will fail on compile.
https://github.com/m5stack/M5Stack/blob/master/examples/Unit/CAN/CAN.ino
C:\Users\Sen\AppData\Local\Arduino15\packages\m5stack\hardware\esp32\2.1.3/tools/sdk/esp32s3/include/soc/esp32s3/include/soc/dport_reg.h:21,
from d:\Arduino\libraries\ESP32CAN\src\CAN.c:38:
d:\Arduino\libraries\ESP32CAN\src\CAN.c: In function 'CAN_init':
d:\Arduino\libraries\ESP32CAN\src\CAN.c:173:26: error: # 'DPORT_PERIP_CLK_EN_REG' undeclared (first use in this function); did you mean 'SYSTEM_PERIP_CLK_EN1_REG'?
DPORT_SET_PERI_REG_MASK(DPORT_PERIP_CLK_EN_REG, DPORT_CAN_CLK_EN);
^~~~~~~~~~~~~~~~~~~~~~
C:\Users\Sen\AppData\Local\Arduino15\packages\m5stack\hardware\esp32\2.1.3/tools/sdk/esp32s3/include/soc/esp32s3/include/soc/dport_access.h:75:67: note: in definition of macro '_DPORT_WRITE_PERI_REG'
#define _DPORT_WRITE_PERI_REG(addr, val) (((volatile uint32_t )(addr))) = (uint32_t)(val)

If use the sample code from here (by using driver/twai.h)
https://github.com/m5stack/M5AtomS3/issues/26
The build is passed but fail to send the message
[ 1000][I][esp32-hal-psram.c:96] psramInit(): PSRAM enabled
[ 1023][I][M5GFX.cpp:732] init_impl(): [M5GFX] [Autodetect] load from NVS : board:10
[ 1026][D][M5GFX.cpp:694] _read_panel_id(): [M5GFX] [Autodetect] read cmd:04 = 7f0000e3
[ 1027][I][M5GFX.cpp:1515] autodetect(): [M5GFX] [Autodetect] board_M5StackCoreS3
[ 1187][V][Touch_FT5x06.cpp:63] _check_init(): [FT5x06] CIPHER:0x64 / FIRMID:0x05 / VENDID:0x02
[ 1190][W][Power_Class.cpp:434] setExtOutput(): [Power] setExtPower(true) is canceled.
[ 1227][V][common.cpp:1403] writeBytes(): [LGFX] i2c write error : ack wait
[ 1228][V][common.cpp:1403] writeBytes(): [LGFX] i2c write error : ack wait
[ 1416][V][common.cpp:1403] writeBytes(): [LGFX] i2c write error : ack wait
[ 1417][V][common.cpp:1403] writeBytes(): [LGFX] i2c write error : ack wait
[ 1419][V][common.cpp:1403] writeBytes(): [LGFX] i2c write error : ack wait
[ 1426][V][common.cpp:1403] writeBytes(): [LGFX] i2c write error : ack wait
[ 1442][V][common.cpp:1403] writeBytes(): [LGFX] i2c write error : ack wait
[ 1452][V][common.cpp:1403] writeBytes(): [LGFX] i2c write error : ack wait
[ 1453][V][common.cpp:1403] writeBytes(): [LGFX] i2c write error : ack wait
[ 1464][V][common.cpp:1403] writeBytes(): [LGFX] i2c write error : ack wait
[ 1465][V][common.cpp:1403] writeBytes(): [LGFX] i2c write error : ack wait
[ 1468][V][common.cpp:1403] writeBytes(): [LGFX] i2c write error : ack wait
Driver installed
Driver started
CAN Alerts reconfigured
Message queued for transmission
Alert: TWAI controller has become error passive.
Alert: A (Bit, Stuff, CRC, Form, ACK) error has occurred on the bus.
Bus error count: 2
Alert: The Transmission failed.
TX buffered: 0 TX error: 136 TX failed: 1
Message queued for transmission
Alert: A (Bit, Stuff, CRC, Form, ACK) error has occurred on the bus.
Bus error count: 3
Alert: The Transmission failed.
TX buffered: 0 TX error: 144 TX failed: 2
Message queued for transmission
Alert: A (Bit, Stuff, CRC, Form, ACK) error has occurred on the bus.
Bus error count: 4
Alert: The Transmission failed.

This is the sample code modified for the CoreS3, PWRCAN jumper G17 and G18 are switch on. Do you have any working demo for CoreS3 + PWRCAN? Thanks!

#include "M5CoreS3.h"
#include "driver/twai.h"

// Pins used to connect to CAN bus transceiver:
#define RX_PIN 18
#define TX_PIN 17

// Interval:
#define TRANSMIT_RATE_MS 1000

#define POLLING_RATE_MS 1000

#define ARDUINO_USB_CDC_ON_BOOT 1

static bool driver_installed = false;

unsigned long previousMillis = 0;  // will store last time a message was send

void setup() {
    auto cfg = M5.config();
    CoreS3.begin(cfg);
    Serial.begin(115200);
    
    // 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_500KBITS();  // Look in the api-reference for other
                                        // speed sets.
    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 TX alerts and Bus-Off errors
    uint32_t alerts_to_enable = TWAI_ALERT_TX_IDLE | TWAI_ALERT_TX_SUCCESS |
                                TWAI_ALERT_TX_FAILED | TWAI_ALERT_ERR_PASS |
                                TWAI_ALERT_BUS_ERROR;
    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 send_message() {
    // Send message

    // Configure message to transmit
    twai_message_t message;
    message.identifier       = 0x0F6;
    message.data_length_code = 4;
    for (int i = 0; i < 4; i++) {
        message.data[i] = 0;
    }

    // Queue message for transmission
    if (twai_transmit(&message, pdMS_TO_TICKS(1000)) == ESP_OK) {
        printf("Message queued for transmission\n");
    } else {
        printf("Failed to queue message for transmission\n");
    }
}

void loop() {
    if (!driver_installed) {
        delay(1000);
        return;
    }

    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);

    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_TX_FAILED) {
        Serial.println("Alert: The Transmission failed.");
        Serial.printf("TX buffered: %lu\t", twaistatus.msgs_to_tx);
        Serial.printf("TX error: %lu\t", twaistatus.tx_error_counter);
        Serial.printf("TX failed: %lu\n", twaistatus.tx_failed_count);
    }
    if (alerts_triggered & TWAI_ALERT_TX_SUCCESS) {
        Serial.println("Alert: The Transmission was successful.");
        Serial.printf("TX buffered: %lu\t", twaistatus.msgs_to_tx);
    }

    unsigned long currentMillis = millis();
    if (currentMillis - previousMillis >= TRANSMIT_RATE_MS) {
        previousMillis = currentMillis;
        send_message();
    }
}