Hi there. Im trying to do a simple project on CAN bus system using ESP32
im having a simple problem when trying to compile a code for CAN bus for ESP32, it seems it is unable understand the library I used
Here is the link of the library I used for my code from arduino
It is unable to compile but if I change to Arduino board, it can compile. Please help 
#include <CAN.h>
#define TX_GPIO_NUM 21 // Connects to CTX
#define RX_GPIO_NUM 22 // Connects to CRX
//==================================================================================//
void setup() {
Serial.begin (115200);
while (!Serial);
delay (1000);
Serial.println ("CAN Receiver/Receiver");
// Set the pins
CAN.setPins (RX_GPIO_NUM, TX_GPIO_NUM);
// start the CAN bus at 500 kbps
if (!CAN.begin (500E3)) {
Serial.println ("Starting CAN failed!");
while (1);
}
else {
Serial.println ("CAN Initialized");
}
}
//==================================================================================//
void loop() {
// canSender();
canReceiver();
}
//==================================================================================//
void canSender() {
// send packet: id is 11 bits, packet can contain up to 8 bytes of data
Serial.print ("Sending packet ... ");
CAN.beginPacket (0x12); //sets the ID and clears the transmit buffer
// CAN.beginExtendedPacket(0xabcdef);
CAN.write ('1'); //write data to buffer. data is not sent until endPacket() is called.
CAN.write ('2');
CAN.write ('3');
CAN.write ('4');
CAN.write ('5');
CAN.write ('6');
CAN.write ('7');
CAN.write ('8');
CAN.endPacket();
//RTR packet with a requested data length
CAN.beginPacket (0x12, 3, true);
CAN.endPacket();
Serial.println ("done");
delay (1000);
}
//==================================================================================//
void canReceiver() {
// try to parse packet
int packetSize = CAN.parsePacket();
if (packetSize) {
// received a packet
Serial.print ("Received ");
if (CAN.packetExtended()) {
Serial.print ("extended ");
}
if (CAN.packetRtr()) {
// Remote transmission request, packet contains no data
Serial.print ("RTR ");
}
Serial.print ("packet with id 0x");
Serial.print (CAN.packetId(), HEX);
if (CAN.packetRtr()) {
Serial.print (" and requested length ");
Serial.println (CAN.packetDlc());
} else {
Serial.print (" and length ");
Serial.println (packetSize);
// only print packet data for non-RTR packets
while (CAN.available()) {
Serial.print ((char) CAN.read());
}
Serial.println();
}
Serial.println();
}
}