MCP2515 CAN Controller Driver for Arduino

` CANMessage Message ; Message.ext=true;

if (gBlinkLedDate < millis ()) { gBlinkLedDate += 1000 ; digitalWrite (LED_BUILTIN, !digitalRead (LED_BUILTIN)) ; Message.id = 0x542; const bool ok = can.tryToSend (Message) ; if (ok) { gSentFrameCount += 1 ; Serial.print ("Sent: ") ; Serial.println (gSentFrameCount) ; }else{ Serial.println ("Send failure") ; } } // if (can.available ()) { Message.ext=true; if (can.receive (Message)){ gReceivedFrameCount ++ ; Serial.println ("Received: ") ; Serial.print ("id: ");Serial.println (Message.id,HEX); Serial.print ("ext: ");Serial.println (Message.ext); Serial.print ("rtr: ");Serial.println (Message.rtr); Serial.print ("len: ");Serial.println (Message.len); Serial.print ("data: "); for(int x=0;x<Message.len;x++) { Serial.print(Message.data[x],HEX);Serial.print(":"); } Serial.println (""); Serial.println (gReceivedFrameCount) ; } }`

standart frame work good (sending and receving) 29bit frame work sending but not receving can.available method return false and can.receive method return false

Hello,

I am using this MKR CAN Shield for an Arduino MKR Wifi 1010. When I try your example "LoopBackDemo.ino" I get the following error:

Configuration error 0x1

This has to with a kTooFarFromDesiredBitRate-issue. But I haven't changed anything on the code and the bitrate is set to:

ACAN2515Settings settings (QUARTZ_FREQUENCY, 125UL * 1000UL) ;

Can this be a problem with the CAN shield itself? I would expect that the LoopBackDemo-code should not give this error.

Thanks in advance, Bart

What did I do wrong within this sketch on arduino UNO? it will send only 17 meassages , then I have "failure" in the serial interface .

< /* * */ #include <ACAN2515.h>

static const byte MCP2515_CS = 10 ; // CS input of MCP2515 (adapt to your design) static const byte MCP2515_INT = 3 ; // INT output of MCP2515 (adapt to your design)

ACAN2515 can (MCP2515_CS, SPI, MCP2515_INT) ;

static const uint32_t QUARTZ_FREQUENCY = 8UL * 1000UL * 1000UL ; // 8 MHz

void setup() {

Serial.begin (38400) ;

while (!Serial) { delay (50) ; digitalWrite (LED_BUILTIN, !digitalRead (LED_BUILTIN)) ; } SPI.begin () ;

ACAN2515Settings settings (QUARTZ_FREQUENCY, 500UL * 1000UL) ; // CAN bit rate 500 kb/s const uint16_t errorCode = can.begin (settings, [] { can.isr () ; }) ; if (errorCode == 0) { Serial.print ("Bit Rate prescaler: ") ; Serial.println (settings.mBitRatePrescaler) ; Serial.print ("Propagation Segment: ") ; Serial.println (settings.mPropagationSegment) ; Serial.print ("Phase segment 1: ") ; Serial.println (settings.mPhaseSegment1) ; Serial.print ("Phase segment 2: ") ; Serial.println (settings.mPhaseSegment2) ; Serial.print ("SJW: ") ; Serial.println (settings.mSJW) ; Serial.print ("Triple Sampling: ") ; Serial.println (settings.mTripleSampling ? "yes" : "no") ; Serial.print ("Actual bit rate: ") ; Serial.print (settings.actualBitRate ()) ; Serial.println (" bit/s") ; Serial.print ("Exact bit rate ? ") ; Serial.println (settings.exactBitRate () ? "yes" : "no") ; Serial.print ("Sample point: ") ; Serial.print (settings.samplePointFromBitStart ()) ; Serial.println ("%") ; }else{ Serial.print ("Configuration error 0x") ; Serial.println (errorCode, HEX) ; } } static uint32_t gBlinkLedDate = 0 ; static uint32_t gReceivedFrameCount = 0 ; static uint32_t gSentFrameCount = 0 ; byte msg[8] = {0, 0, 0, 0, 0, 0, 0, 0};

void loop() {

byte msg[8] = { 12, 23, 33, 44, 55, 66, 77, 28};

CANMessage frame ; frame.id = 31 ; frame.ext = true ; frame.rtr = false ; frame.idx = 0 ; frame.len = 8 ; for (int i=0 ; i<8 ; i++) { frame.data [i] = {msg[i]} ; }
/* frame.data [0] = {egt[1]} ; frame.data [1] = {egt[2]} ; frame.data [2] = 33 ; frame.data [3] = 44 ; frame.data [4] = 55 ; frame.data [5] = 66 ; frame.data [6] = 77 ; frame.data [7] = 88 ;
*/
if (gBlinkLedDate < millis ()) { gBlinkLedDate += 50 ; digitalWrite (LED_BUILTIN, !digitalRead (LED_BUILTIN)) ; const bool ok = can.tryToSend (frame) ; if (ok) { gSentFrameCount += 1 ; Serial.print ("Sent: ") ; Serial.println (gSentFrameCount) ; }else{ Serial.println ("Send failure") ; } } }

Pierre,

Just to let you know that your library works fine on the Raspberry Pi Pico with the 'unofficial' core: https://github.com/earlephilhower/arduino-pico

The Pico SPI peripherals can use any pins, and there are no defaults, so you need to explicitly set these before initialising the library. The Pico has two SPI peripherals, SPI and SPI1, so you could use either (or both).

#include <SPI.h>

static const byte PICO_INT = 1;
static const byte PICO_SCK = 2;
static const byte PICO_MOSI = 3;
static const byte PICO_MISO = 4;
static const byte PICO_CS = 5;

// configure SPI pins
SPI.setSCK(PICO_SCK);   // SCK
SPI.setTX(PICO_MOSI);   // MOSI
SPI.setRX(PICO_MISO);   // MISO
SPI.setCS(PICO_CS);     // CS

There was a minor bug in the core (NOT_AN_INTERRUPT was not #defined) but this has been fixed now.

Let me know if you want to support this board explicitly and I'd be happy to test any changes.

Work is in progress by the Arduino project on an 'official' core for the Pico.

Hi, Pierre

I got a question on RTR frames. I want to tell apart whether a received message is a RTR frame by the value of RTR bit. But when I sent a RTR frame with RTR bit == 1, and tried to use a filter to receive it, in the end the RTR bit of this received message becomes 0.

Then I notice that in the ACAN2515 document, section 9.2 on page 20, it says :

Filter remote and data frames. The MCP2515 filters do not handle the RTR bit: for example, you cannot specify you want to accept data frames and discard remote frames. This should be done by your code.

Does that mean a filter will set the RTR bit to 0 automatically, even I set it to 1 before sending? If that is true, to tell apart a RTR frame, do I have to manually dispatch the received messages as decribed in section 8 on page 18?

Bonjour Pierre,

Je teste votre bibliothèque avec un shield seeeds et un Arduino UNO sans aucun problème. Mais je n'arrive pas avec un MEGA.

Voici mes réglages

`//—————————————————————————————————————————————————————————————————————————————— // ACAN2515 Demo in loopback mode //——————————————————————————————————————————————————————————————————————————————

#include <ACAN2515.h> //—————————————————————————————————————————————————————————————————————————————— // MCP2515 connections: // - standard SPI pins for SCK, MOSI and MISO // - a digital output for CS // - interrupt input pin for INT //—————————————————————————————————————————————————————————————————————————————— // If you use CAN-BUS shield (http://wiki.seeedstudio.com/CAN-BUS_Shield_V2.0/) with Arduino Uno, // use B connections for MISO, MOSI, SCK, #9 or #10 for CS (as you want), // #2 or #3 for INT (as you want). //——————————————————————————————————————————————————————————————————————————————

#ifdef ARDUINO_AVR_MEGA2560

static const byte MCP2515_SCK = 52 ; // SCK input of MCP2515 static const byte MCP2515_SI = 51 ; // SI output of MCP2515 static const byte MCP2515_SO = 50 ; // S0 output of MCP2515

static const byte MCP2515_CS = 53 ; // CS input of MCP2515 static const byte MCP2515_INT = 2 ; // INT output of MCP2515

#endif

#ifdef ARDUINO_AVR_UNO

static const byte MCP2515_SCK = 13 ; // SCK input of MCP2515 static const byte MCP2515_SI = 11 ; // SI output of MCP2515 static const byte MCP2515_SO = 12 ; // S0 output of MCP2515

static const byte MCP2515_CS = 10 ; // CS input of MCP2515 static const byte MCP2515_INT = 2 ; // INT output of MCP2515

#endif`

Merci pour votre aide.

Christophe

Wanting to use your library on a Pi Pico, sitting on a prebuilt circuit board that has an SPI device (MCP2515) on the 'default' SPI pins of the Pi Pico module (GPIO 16 - 19)

Unfortunately, the 'standard' Arduino SPI library uses GPIO2 - GPIO5 - I've proved this by running an SPI 'loopback' test And I see your library uses this library <SPI.H> The default <SPI.H> doesn't appear to allow you to redefine the pins used

Any idea how I can resolve this? (I'd rather not cut pcb tracks to re-work the physical pins)

I did get the SPI test working on the 'default' pins using <mbed.h> instead of <SPI.H>, as <mbed.h> allows you to redefine the pins used, but the syntax of the SPI functions seems to be slightly different, and of course your library uses <SPI.H>, so I don't see how that helps

If it's any use, here's the build info for the working test I mentioned using <SPI.H>

` PLATFORMPLATFORM: Raspberry Pi RP2040 (1.5.0) > Raspberry Pi Pico HARDWARE: RP2040 133MHz, 264KB RAM, 2MB Flash DEBUG: Current (cmsis-dap) External (cmsis-dap, jlink, raspberrypi-swd)
PACKAGES:

• framework-arduino-mbed 2.6.1
• tool-rp2040tools 1.0.2
• toolchain-gccarmnoneeabi 1.90201.191206 (9.2.1) `

It would be very useful to be able to read the chip's error flag register (0x2D ?) This enables one to check for error states such as warning level, error passive, bus off, etc. A value of zero means 'no error' and the definitions of the individual bit values can be found in the datasheet.

It is present in the MCP_CAN library as the getError() method.

Can you check why This code can print standard can id but not ext can id. If I receive 11 bit ID then it can receive ok but if i receive 29 bit id then the loop function never print anything. Note that in my BUS have 11 bit ID and 29Bit ID too ` #include <ACAN2515.h> CANMessage canMsg_rx; static const byte MCP2515_CS1 = 10 ; // CS input of MCP2515 CAN1 static const byte MCP2515_INT1 = 2 ; // INT output of MCP2515 CAN1 ACAN2515 CAN1(MCP2515_CS1, SPI, MCP2515_INT1); static const uint32_t QUARTZ_FREQUENCY = 16UL * 1000UL * 1000UL; // 16 MHz void setup() { Serial.begin (115200) ; while (!Serial) { delay (50) ; } SPI.begin(); ACAN2515Settings settings (QUARTZ_FREQUENCY, 500 * 1000UL); settings.mTransmitBuffer0Size = 5 ; settings.mTransmitBuffer1Size = 0 ; settings.mTransmitBuffer2Size = 0 ; settings.mReceiveBufferSize = 5 ; settings.mRequestedMode = ACAN2515Settings::NormalMode; const uint16_t errorCode1 = CAN.begin(settings, [] {CAN.isr();}); if (errorCode1 != 0) { Serial.print ("Configuration CAN error 0x") ; Serial.println (errorCode1, HEX) ; } else { Serial.println ("Configuration CAN OK!") ; } }

void loop() { if (CAN.receive(canMsg_rx)) { Serial.println(canMsg_rx.id, HEX); } }

`

Sometimes, under heavy receive load, the RX0OVR bit in the error flag register get 'stuck' on. The errorFlagRegister() method returns 64. It's difficult to reproduce reliably.

RX0OVR: Receive Buffer 0 Overflow Flag bit Sets when a valid message is received for RXB0 and RX0IF (CANINTF[0]) = 1 - Must be reset by MCU

It does coincide with a 'lost' message at the application level (I track a message sequence number in my code). Only a power cycle or grounding the reset pin will resolve it.

I am not using interrupts and am polling frequently for new messages. Receive buffers = 8 but the high watermark is never above 2.

Any thoughts ? Thanks.

MCU is an AVR (1284P).

Using this with MKR Zero and MKR Can Shield. My program freezes randomly without crashing. I've tested on SRAM overflow, memory corruption etc and everything should work fine.

I'm currently suspecting it has todo with the ACAN2515::isr_core routine MCP2515 Datasheet says that one have to set every intflag to zero with BIT_MODIFY command. But in the isr_core routine if an Error Interrupt or Wake-Up Interrupt flag is set. It will never bet unset so the while loop will never exit.

I've probably missed something on why you do that. But can you explain me on how the while loop in ACAN2515::isr_core will exit when Error or Wakeup Intflag is set?

Hi Pierre

I am trying to use your library for an MCP2515 connected to a Raspberry Pi Pico. Using your LoopBackDemo sketch (among others), it seems that the configuration of the MCP2515 runs fine.

However, when it comes to transmitting and receiving frames, it only prints "Sent: 1" up to "Sent: 17". As you explain in the sketch's comments, this indicates to be a problem with the interrupt. I have checked the INT pin on the MCP2515 with an oscilloscope while running the sketch, and it doesn't generate an interrupt on that pin. Could there perhaps be something that is not configured correctly when the MCP2515 is initialised?

I see that in the function internalBeginOperation() you write the value 0x1F to register CANINTE, which enables the TX and RX interrupts, so I would expect the interrupt to work when the frames are sent. However, this doesn't happen.

My test is performed using a 12 MHz crystal and the Raspberry Pi Pico. The same test performed with an Arduino Due has the same result.

What could be the cause of this?

Thank you in advance.

I have a raspberry pi pico, using Arduino official mbed rp2040 core framework-arduino-mbed 2.6.1 tool-rp2040tools 1.0.2 When I test the 'generic' LoopBackDemo sketch, my pico crashes on the can.tryToSend call and the LED blinks 4 short and 4 long and repeat. (the "LoopBackDemoRaspberryPiPico" doesn't compile with the offical mbed core, it seems to use other 'SPI' commands)

The "Configure ACAN2515" section runs fine and prints out the expected results (attached below)

So, I'm assuming the SPI is talking to the MCP2515 just fine?

If I comment out the can.tryToSend (with a true return) the loop runs fine

I saw a similar previous issue here but that crashed at can.begin(), which isn't my issue (my code runs past this command), so although I tried their work around, not surprisingly it didn't help ` Any idea what I could try or what to look at to resolve this?

Bit Rate prescaler: 4 Propagation Segment: 5 Phase segment 1: 5 Phase segment 2: 5 SJW: 4 Triple Sampling: yes Actual bit rate: 125000 bit/s Exact bit rate ? yes Sample point: 62% `

I'm connecting 3 MCP2515 to esp32 each of which Initializing is done After that, some MCP2515 stops are available to esp32. I measure single CS and INT during not a response to esp32, CS always HIGH and INT always LOW.

My setup // Init CAN SPI.begin();

ACAN2515Settings settings1(QUARTZ_FREQUENCY, 500UL * 1000UL); // 500 kpbs
ACAN2515Settings settings2(QUARTZ_FREQUENCY, 500UL * 1000UL); // 500 kpbs
ACAN2515Settings settings3(QUARTZ_FREQUENCY, 500UL * 1000UL); // 500 kpbs

settings1.mRequestedMode = ACAN2515Settings::NormalMode;
settings1.mReceiveBufferSize = 100;
uint16_t errorCode1 = can1.begin(settings1, []
                                 { can1.isr(); });

delay(50);

settings2.mRequestedMode = ACAN2515Settings::NormalMode;
settings2.mReceiveBufferSize = 100;
uint16_t errorCode2 = can2.begin(settings2, []
                                 { can2.isr(); });

delay(50);

settings3.mRequestedMode = ACAN2515Settings::NormalMode;
settings3.mReceiveBufferSize = 100;
uint16_t errorCode3 = can3.begin(settings3, []
                                 { can3.isr(); });

delay(50);

Firstly thank you for this library it is very very useful.

I'm trying to understand the sleep function, would it be possible to add to your examples, that would be great.

At the moment I put the transiever in standby then change the mode to sleep. I have also enabled the interrupt pins wake on CAN function.

When there is traffic on the CAN the interrupt works, I then take the transiever out of standby and change the mode to normal. The return value from the changeModeOnTheFly function is 0, so appears good.

I then use CAN tryandsend (which returns true) but nothing appears on the CAN bus where as it did before I put the unit into sleep.

If I don't put the can transiever into stanby and only use sleep the same happens.

When I come out of sleep mode the can recieve message appears to be constanlty fired as if the read register bit is not being cleared anymore....

I could well be doing something wrong and thanks for any help.

Hi I have a raspberry pi pico, using Arduino offical mbed rp2040 board. When I test the LoopBackDemoRaspberryPiPICO sketch, my pico crashes and the LED blinks 4 short and 4 long and repeat. With some digging in(insert Serial.println into src/ACAN2515.cpp), I found that it crashes at the mSPI.beginTransaction (mSPISettings) ; line in fuction ACAN2515::beginWithoutFilterCheck, then I checked this line: mSPISettings (10UL * 1000UL * 1000UL, MSBFIRST, SPI_MODE0),, after reading the comment, I think maybe the "UL suffix" is incompatible with offical mbed rp2040 board, so I simply changed the frequency to 10000000, and uploaded the sketch, my pico never crashes! I don't know how to edit the cpp to adapt both AVR arduino and rpi pico, so I just report this bug. Thanks for your hardwork. qwec01