@
SyRus, you’re right, MCP2515 works perfectly (correction – I mean not the shield, but the MCP2515 chip itself
).
My first mistake was to connect CAN bus directly to the board (CAN TX, RX).
Second fail was because TJA1050 that I tried was defective (infinite resistance between CAN Hi – CAN Lo).
Third – both TJA1050 and MCP2515 must be supplied with 5V to be able to send messages.
I’ve simplified the code by Phono to just send a message for test reasons:
// HardwareCAN_simplified_send1.ino
#include <HardwareCAN.h>
//#include "changes.h"
/*
* Example of use of the HardwareCAN library
* Please read the file changes.h to see the changes to be performed to the core in order to use this
*/
byte msgD0 ; // variable to be used in the example.
// Instanciation of CAN interface
HardwareCAN canBus(CAN1_BASE);
CanMsg msg ;
void CANSetup(void)
{
CAN_STATUS Stat ;
// Initialize CAN module
canBus.map(CAN_GPIO_PB8_PB9); // This setting is already wired in the Olimexino-STM32 board
Stat = canBus.begin(CAN_SPEED_125, CAN_MODE_NORMAL); // Other speeds go from 125 kbps to 1000 kbps. CAN allows even more choices.
canBus.filter(0, 0, 0);
canBus.set_irq_mode(); // Use irq mode (recommended), so the handling of incoming messages
// will be performed at ease in a task or in the loop. The software fifo is 16 cells long,
// allowing at least 15 ms before processing the fifo is needed at 125 kbps
Stat = canBus.status();
if (Stat != CAN_OK)
/* Your own error processing here */ ; // Initialization failed
}
// Send one frame. Parameter is a pointer to a frame structure (above), that has previously been updated with data.
// If no mailbox is available, wait until one becomes empty. There are 3 mailboxes.
CAN_TX_MBX CANsend(CanMsg *pmsg) // Should be moved to the library?!
{
CAN_TX_MBX mbx;
do
{
mbx = canBus.send(pmsg) ;
#ifdef USE_MULTITASK
vTaskDelay( 1 ) ; // Infinite loops are not multitasking-friendly
#endif
}
while(mbx == CAN_TX_NO_MBX) ; // Waiting outbound frames will eventually be sent, unless there is a CAN bus failure.
return mbx ;
}
// Send message
// Prepare and send a frame containing some value
void SendCANmessage(long id=0x001, byte d0=0x00, byte d1=0x00, byte d2=0x00, byte d3=0x00, byte d4=0x00, byte d5=0x00, byte d6=0x00, byte d7=0x00)
{
// Initialize the message structure
// A CAN structure includes the following fields:
msg.IDE = CAN_ID_STD; // Indicates a standard identifier ; CAN_ID_EXT would mean this frame uses an extended identifier
msg.RTR = CAN_RTR_DATA; // Indicated this is a data frame, as opposed to a remote frame (would then be CAN_RTR_REMOTE)
msg.ID = id ; // Identifier of the frame : 0-2047 (0-0x3ff) for standard idenfiers; 0-0x1fffffff for extended identifiers
msg.DLC = 8; // Number of data bytes to follow
// Prepare frame : send something
msg.Data[0] = d0 ;
msg.Data[1] = d1 ;
msg.Data[2] = d2 ;
msg.Data[3] = d3 ;
msg.Data[4] = d4 ;
msg.Data[5] = d5 ;
msg.Data[6] = d6 ;
msg.Data[7] = d7 ;
digitalWrite(PC13, LOW); // turn the onboard LED on
CANsend(&msg) ; // Send this frame
delay(180);
digitalWrite(PC13, HIGH); // turn the LED off
delay(100);
}
// The application program starts here
void setup() {
// put your setup code here, to run once:
CANSetup() ; // Initialize the CAN module and prepare the message structures.
pinMode(PC13, OUTPUT);
msgD0 = 0x01;
}
void loop() {
delay(1000);
long msgID = 0x101 ;
SendCANmessage(msgID, msgD0) ;
msgD0++;
}
