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Comments: AST-CAN485 Hookup Guide

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Looking for answers to technical questions?

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  • Member #1645551 / about a year ago / 1

    ON AST-CAN485, how do I check whether there is a message already received in the buffers/MOBs? The example code's shows how to receive the message, and it waits for a message to come in. In my application I'd like to check whether there is a message, process it if there is one, and perform other tasks if there is none, then loop.

  • stephan schulz / about 6 years ago / 1

    I installed board and libraries as per the guide on macos and windows. But both give me this following error message when trying to compile.

    WARNING: Category 'Communications' in library AST_CAN is not valid. Setting to 'Uncategorized'
WARNING: Category 'Communications' in library AST_RS485 is not valid. Setting to 'Uncategorized'
Sketch uses 1072 bytes (0%) of program storage space. Maximum is 130048 bytes.
Global variables use 9 bytes (0%) of dynamic memory, leaving 4087 bytes for local variables. Maximum is 4096 bytes.
avrdude: verification error, first mismatch at byte 0x0000
0x14 != 0x0c
avrdude: verification error; content mismatch
avrdude: verification error; content mismatch

    What am I doing wrong?

    • Member #1442119 / about 6 years ago / 1

      I was getting these same errors with two of these setup one as CAN transmitter, one as CAN receiver. On the receiver in void setup i entered pinMode(13, OUTPUT); to use the onboard LED to indicate it saw a change in a CAN packet byte. I think the problem was this is SCK, serial clock, pin also. Once I uploaded the program i wouldn't be able to load another program to it until i reburned the bootloader to the board with an Arduino. Arduino IDE would just give me content mismatch and say board is not connected.

      • Member #1001047 / about 4 years ago / 1

        Hi, I know this is an old topic but could you please leave me some information about this procedure?

  • Member #1458150 / about 6 years ago / 1

    How can I use the AST CAN as receiver and transmitter in one. I have to send messages in a CAN Network, but also have to answer.

    • Member #1442119 / about 6 years ago * / 0

      this is kind of a crude way to do it but I put this program on both can485 boards. the only difference is the message ID between the two. Each one is getting a pushbutton input to pin 2 that can turn on output pin 5 on the other board

      #include <ASTCanLib.h>  

#define MESSAGE_ID        250
#define MESSAGE_PROTOCOL  1
#define MESSAGE_LENGTH    8 
#define MESSAGE_RTR       0 

 st_cmd_t Msg;

 uint8_t Buffer[8] = {};

 void setup() {
  canInit(500000);                  // Initialise CAN port. must be before Serial.begin
  Serial.begin(1000000);             // start serial port
  Msg.pt_data = &Buffer[0];      // reference message data to transmit buffer
  pinMode(5, OUTPUT);
  Msg.ctrl.ide = MESSAGE_PROTOCOL;  // Set CAN protocol (0: CAN 2.0A, 1: CAN 2.0B)
  Msg.id.ext   = MESSAGE_ID;        // Set message ID
  Msg.dlc      = MESSAGE_LENGTH;    // Data length: 8 bytes
  Msg.ctrl.rtr = MESSAGE_RTR;       // Set rtr bit
  }

void loop() {
tx:
  int buttonState = digitalRead(2);
  if (buttonState == HIGH){

    Buffer[0] = 10;
  Msg.ctrl.ide = MESSAGE_PROTOCOL;  // Set CAN protocol (0: CAN 2.0A, 1: CAN 2.0B)
  Msg.id.ext   = MESSAGE_ID;        // Set message ID
  Msg.dlc      = MESSAGE_LENGTH;    // Data length: 8 bytes
  Msg.ctrl.rtr = MESSAGE_RTR;       // Set rtr bit
  Msg.cmd = CMD_TX_DATA;      
  while(can_cmd(&Msg) != CAN_CMD_ACCEPTED);
  while(can_get_status(&Msg) == CAN_STATUS_NOT_COMPLETED);
    goto tx;}
    else{Buffer[0] = 30;
           Msg.ctrl.ide = MESSAGE_PROTOCOL;  // Set CAN protocol (0: CAN 2.0A, 1: CAN 2.0B)
  Msg.id.ext   = MESSAGE_ID;        // Set message ID
  Msg.dlc      = MESSAGE_LENGTH;    // Data length: 8 bytes
  Msg.ctrl.rtr = MESSAGE_RTR;       // Set rtr bit
        Msg.cmd = CMD_TX_DATA;      
  while(can_cmd(&Msg) != CAN_CMD_ACCEPTED);
  while(can_get_status(&Msg) == CAN_STATUS_NOT_COMPLETED);
    }

Msg.cmd = CMD_RX_DATA;
while(can_cmd(&Msg) != CAN_CMD_ACCEPTED);
while(can_get_status(&Msg) == CAN_STATUS_NOT_COMPLETED);

if (Buffer[0] == 10){
    digitalWrite(5, HIGH);}
    else if (Buffer[0] == 30) {
    digitalWrite(5, LOW);}
}

  • Member #736640 / about 7 years ago / 1

    the software installation does not work,

    the board manager url does not exist:

    https://raw.githubusercontent.com/Atlantis-Specialist-Technologies/ast-arduino-boards/master/boards-manager-files/package_ast_boards_index.json

  • Member #736640 / about 7 years ago / 1

    the links you provided for schematic and datasheet are "dead": --> https://github.com/Atlantis-Specialist-Technologies-Admin/CAN485/blob/master/Documentation/Datasheet%20AT90CANXX.pdf --> https://github.com/Atlantis-Specialist-Technologies-Admin/CAN485/blob/master/Documentation/CAN485%201.0.0.pdf

    the referring github repo seems to be empty: --> https://github.com/Atlantis-Specialist-Technologies-Admin

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