Hello all, I am new to the Forum and to the Teensy devices.
I am working on a CAN-ModbusTCP bridge, with a Teensy 4.1 and native PHY Ethernet.
Currently, I have this project working good with an Arduino Mega 2560, Ethernet shield W5500 and CAN shield MCP2515. Everything works and I have a cycle time of about 12 ms, which is good but I would like to improve.
I have ported the code to Teensy, using the libraries QNEthernet and FlexCAN_T4. The Modbus library is the same official one for Arduino "ArduinoModbus".
On the CAN side, it works flawless. Fast and reliable, using mailboxes and filtering.
BUT the ModbusTCP side, I have configured it as ModbusTCP server, and another device communicates as a client to it.
Each time there is a package received (especially when the external device writes holding registers), it delays a lot, making the whole thing unusable.
I have tried both NativeEthernet and QNEthernet libraries. The latter works better but still delays the communication.
This is the main part of the code. Please note MTCP_zz, MTCP_xx and so on are all very similar.
I am working on a CAN-ModbusTCP bridge, with a Teensy 4.1 and native PHY Ethernet.
Currently, I have this project working good with an Arduino Mega 2560, Ethernet shield W5500 and CAN shield MCP2515. Everything works and I have a cycle time of about 12 ms, which is good but I would like to improve.
I have ported the code to Teensy, using the libraries QNEthernet and FlexCAN_T4. The Modbus library is the same official one for Arduino "ArduinoModbus".
On the CAN side, it works flawless. Fast and reliable, using mailboxes and filtering.
BUT the ModbusTCP side, I have configured it as ModbusTCP server, and another device communicates as a client to it.
Each time there is a package received (especially when the external device writes holding registers), it delays a lot, making the whole thing unusable.
I have tried both NativeEthernet and QNEthernet libraries. The latter works better but still delays the communication.
This is the main part of the code. Please note MTCP_zz, MTCP_xx and so on are all very similar.
Code:
#include <SPI.h>
#include <NativeEthernet.h>
#include <ArduinoRS485.h> // ArduinoModbus depends on the ArduinoRS485 library
#include <ArduinoModbus.h>
#include <FlexCAN_T4.h>
FlexCAN_T4<CAN1, RX_SIZE_256, TX_SIZE_16> Can0;
CAN_message_t msgr;
#define NUM_RX_MAILBOXES 11
#define NUM_TX_MAILBOXES 3
#define NUMB 10
int16_t pv[NUMB];
bool pe[NUMB];
bool pp[NUMB];
bool pa[NUMB];
uint8_t mac[] = {
0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED
};
IPAddress ip(10,0,0,20); //bridge IP
EthernetServer ethServer(502);
ModbusTCPServer modbusTCPServer;
unsigned long previousMillis = 0;
const long interval = 1000;
uint32_t tcicloprev;
const int ledPin = 13;
void setup() {
pinMode(ledPin, OUTPUT);
digitalWrite(ledPin, LOW);
Serial.begin(115200);
Ethernet.begin(mac, ip);
// start the server
ethServer.begin();
if (!modbusTCPServer.begin()) {
while (1);
}
modbusTCPServer.configureCoils(0x00, 64);
modbusTCPServer.configureHoldingRegisters(0x00, 256);
Can0.begin();
Can0.setBaudRate(250000);
Can0.setMaxMB(NUM_TX_MAILBOXES + NUM_RX_MAILBOXES);
for (int i = 0; i<NUM_RX_MAILBOXES; i++){
Can0.setMB((FLEXCAN_MAILBOX)i,RX,STD);
}
for (int i = NUM_RX_MAILBOXES; i<(NUM_TX_MAILBOXES + NUM_RX_MAILBOXES); i++){
Can0.setMB((FLEXCAN_MAILBOX)i,TX,STD);
}
Can0.setMBFilter(REJECT_ALL);
Can0.enableMBInterrupts();
Can0.onReceive(MB0,canSniff);
Can0.onReceive(MB1,canSniff);
Can0.onReceive(MB2,canSniff);
Can0.onReceive(MB3,canSniff);
Can0.onReceive(MB4,canSniff);
Can0.onReceive(MB5,canSniff);
Can0.onReceive(MB6,canSniff);
Can0.onReceive(MB7,canSniff);
Can0.onReceive(MB8,canSniff);
Can0.onReceive(MB9,canSniff);
Can0.onReceive(MB10,canSniff);
Can0.setMBFilter(MB0,10);
Can0.setMBFilter(MB1,20);
Can0.setMBFilter(MB2,30);
Can0.setMBFilter(MB3,40);
Can0.setMBFilter(MB4,50);
Can0.setMBFilter(MB5,60);
Can0.setMBFilter(MB6,70);
Can0.setMBFilter(MB7,80);
Can0.setMBFilter(MB8,90);
Can0.setMBFilter(MB9,100);
Can0.setMBFilter(MB10,110);
Can0.mailboxStatus();
}
void canSniff(const CAN_message_t &msg) {
Serial.print("MB "); Serial.print(msg.mb);
Serial.print(" OVERRUN: "); Serial.print(msg.flags.overrun);
Serial.print(" LEN: "); Serial.print(msg.len);
Serial.print(" EXT: "); Serial.print(msg.flags.extended);
Serial.print(" TS: "); Serial.print(msg.timestamp);
Serial.print(" ID: "); Serial.print(msg.id, HEX);
Serial.print(" Buffer: ");
for ( uint8_t i = 0; i < msg.len; i++ ) {
Serial.print(msg.buf[i], HEX); Serial.print(" ");
}
Serial.println();
for (uint8_t i=1; i<NUMB+1; i++){
if (msg.id == (10+(i*10))){
if (msg.len == 2){
pp[i] = msg.buf[1];
pa[i] = msg.buf[0];
}
if (msg.len == 3){
pv[i] = (msg.buf[0]*256) + msg.buf[1];
if (msg.buf[2]==0x20) { pe[i] = true;}
else { pe[i] = false;}
}
}
}
}
void loop() {
EthernetClient client = ethServer.available();
if (client) {
modbusTCPServer.accept(client);
while (client.connected()) {
// poll for Modbus TCP requests, while client connected
modbusTCPServer.poll();
Can0.events();
MTCP_zz();
//MTCP_xx();
//MTCP_yy();
//MTCP_tt();
}//END WHILE
client.stop();
}//END MODBUS
}
void myCallback() {
Serial.println("FEED THE DOG SOON, OR RESET!");
}
void MTCP_zz(){
uint16_t zz = 0;
CAN_message_t msg;
msg.buf[0]=25;
zz = modbusTCPServer.holdingRegisterRead(0x04);
if(zz != 0){
for (int8_t i = 0; i<15; i++){
if (bitRead(zz,i) == 1)
{
msg.id = 0x101+(i*10);
Can0.write(MB12,msg);
bitClear(zz,i);
}
}
modbusTCPServer.holdingRegisterWrite(0x04, zz);
}
}
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