I am currently in the process of writing some code for the PCAN-RS232 module, and I am having issues with the CAN communication. The function of the code is to:
- Get values from an incoming CAN message and encode it into a serial message as a setpoint for an RS232 device (MFC – mass flow controller)
- Request the feedback from the MFC via RS232, read the response, and encode it into a different outgoing CAN message
The CAN network is very lightly loaded, just the relevant incoming message is sent via PCAN-View every 100 ms. The issue I am having is that the reception of the CAN messages on the PCAN-RS232 is often showing:
- CAN messages received with the correct ID, but the wrong content
- CAN messages with fictitious IDs are being received
Here are some snippets of how the CAN driver is configured:
Code: Select all
//At startup
void CAN_UserInit ( void)
{
// init CAN1
CAN_ReferenceTxQueue ( CAN_BUS1, &TxQueueCAN1[0], CAN1_TX_QUEUE_SIZE); // Reference above Arrays as Queues
CAN_ReferenceRxQueue ( CAN_BUS1, &RxQueueCAN1[0], CAN1_RX_QUEUE_SIZE);
CAN_SetTimestampHandler ( CAN_BUS1, NULL);
VICVectAddr1 = (u32_t) CAN_GetIsrVector ( CAN1_TX_INTSOURCE);
VICVectAddr3 = (u32_t) CAN_GetIsrVector ( CAN1_RX_INTSOURCE);
VICVectCntl1 = 1 << 5 | CAN1_TX_INTSOURCE; // Setup VIC
VICVectCntl3 = 1 << 5 | CAN1_RX_INTSOURCE;
VICIntEnable = 1 << CAN1_TX_INTSOURCE | 1 << CAN1_RX_INTSOURCE;
CAN_SetErrorLimit ( CAN_BUS1, STD_TX_ERRORLIMIT);
CAN_SetTxErrorCallback ( CAN_BUS1, NULL); // Set ErrorLimit & Callbacks
CAN_SetRxCallback ( CAN_BUS1, NULL);
CAN_SetChannelInfo ( CAN_BUS1, NULL); // Textinfo is NULL
// Set Error Handler
VICVectAddr0 = (u32_t) CAN_GetIsrVector ( GLOBAL_CAN_INTSOURCE);
VICVectCntl0 = 1 << 5 | GLOBAL_CAN_INTSOURCE;
VICIntEnable = 1 << GLOBAL_CAN_INTSOURCE;
// Setup Filters
CAN_InitFilters(); // Clear Filter LUT
CAN_FilterAddId(CAN_BUS1, FILTER_11BIT_ID, CANMSG_SETPOINT_ID);
CAN_FilterAddId(CAN_BUS1, FILTER_11BIT_ID, CANMSG_SUPPLYPRESSURE_ID);
CAN_SetFilterMode ( AF_ON); // No Filters ( Bypassed)
// init CAN1
CAN_InitChannel ( CAN_BUS1, CAN_BAUD_500K);
//
CAN_SetTransceiverMode ( CAN_BUS1, CAN_TRANSCEIVER_MODE_NORMAL);
// Buses on
CAN_SetBusMode ( CAN_BUS1, BUS_ON); // CAN Bus On
}
Code: Select all
stCANStatus = CAN_UserRead ( CAN_BUS1, &RxMsg);
if (stCANStatus == CAN_ERR_OK)
{
#if DEBUG_MODE
ctsBufferLength = sprintf(txSerialBufferSend, "CAN message received, ID is %d\r\n",RxMsg.Id);
SER_Write(SER_PORT1, txSerialBufferSend, ctsBufferLength);
#endif
if (RxMsg.Id == CANMSG_SETPOINT_ID) {
tiLastSetpointMsgReceived = SYSTIME_NOW;
// message received from CAN1
LED_toggleCAN1 ^= 1;
if ( LED_toggleCAN1)
{
HW_SetLED ( HW_LED_CAN1, HW_LED_ORANGE);
}
else
{
HW_SetLED ( HW_LED_CAN1, HW_LED_GREEN);
}
// TODOConvert setpoint and send it to serial
// SG_ dmFuelFcmH2DesByp : 0|16@1+ (0.0009765625,0) [0|65535] "mg/s" Vector__XXX
dmSetpoint = (float)(RxMsg.Data16[0]*FLOW_CAN_SCALING); // ToDo we need to swap the bytes?
if (dmSetpoint > dmSetpointMax)
{
dmSetpoint = dmSetpointMax;
} else {
if (dmSetpoint < 0)
{
dmSetpoint = 0;
}
}
ctFlowSetpoint = (u16_t)(dmSetpoint*facDmSetpointToBronkhorstSetpoint);
#if DEBUG_MODE
ctsBufferLength = sprintf(txSerialBufferSend, "Flow setpoint received: %f, converted to %d\r\n", dmSetpoint,ctFlowSetpoint);
SER_Write(SER_PORT1, txSerialBufferSend, ctsBufferLength);
#endif
ctsBufferLength = sprintf(txtCtSetpoint, "%04x", ctFlowSetpoint); // FIXME - check formatting
ctsBufferLength = sprintf(txSerialBufferSend, ":0601010121%s\r\n", txtCtSetpoint); // FIXME THIS SHOULD CONTAIN THE SETPOINT
SER_Write(SER_PORT1, &txSerialBufferSend, ctsBufferLength);
// TODO add checking the response
} else {
if (RxMsg.Id == CANMSG_SUPPLYPRESSURE_ID)
{
// Just copy it across to another variable
ctPSpl = RxMsg.Data16[2];
#if DEBUG_MODE
ctsBufferLength = sprintf(txSerialBufferSend, "Pressure received: %d\r\n", ctPSpl);
SER_Write(SER_PORT1, txSerialBufferSend, ctsBufferLength);
#endif
} else {
// Do nothing
#if DEBUG_MODE
ctsBufferLength = sprintf(txSerialBufferSend, "Message %d not recognised\r\n",RxMsg.Id);
SER_Write(SER_PORT1, txSerialBufferSend, ctsBufferLength);
#endif
}
}
}
I have tried to use the highlighting as much in order to facilitate the interpretation.CAN message received, ID is 1903
Flow setpoint received: 3.203125, converted to 3422
:06010101210d5e
:06030401210120
:0401000000
CAN message received, ID is 4
Message 4 not recognised
:06030401210120
CAN message received, ID is 1
:06010101212485
:06030401210120
:0401000000
CAN message received, ID is 1903
Flow setpoint received: 8.750977, converted to 9349
:06010101212485
:06030401210120
:0401000000
CAN message received, ID is 1073745340
Message 1073745340 not recognised
:06030401210120
:0401000000
CAN message received, ID is 54648
Message 54648 not recognised
:06030401210120
CAN message received, ID is 0
:06010101210d5e
CAN message received, ID is 1903
Flow setpoint received: 8.750977, converted to 9349
:06010101212485
:06030401210120
- The messages highlighted in blue are sent by my laptop using RealTerm.
- Some incorrect messages are often showing (highlighted in red), plus the correct message (1903) often has the wrong content (3422 - yellow) rather than the correct one (9349 - green).
The further outputs on the serial are part of a different functionality on the code.
