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I've got a CAN network of 7 controllers which are communicating at 500Kbit/s baud rate successfully. The problem is when sometimes one or some of the controllers give up on communication until restarted. I'm observing the following behaviour - I start the power supply and all the controllers begin sending heartbeat packages at 2Hz rate. If I connect the JTAG to one of the controllers and if I catch it behaving strangely it goes like this: After a while on the CANES register I start to see some FE, SE and BE which I acknowledge by writing 1 to them via the Code composer studio debugger. After some more time I can see the EW and EP registers both got 1 and the CCE bit set to 1. The controller continues to work, but the CAN module stops sending or receiving anything. CANES looks like this - CCE = 1, EW = 1, EP = 1, everything else is 0. CCE = 1 is the default state after reset, so I'm wondering what is going on with the controllers.
Usually I can see them communicating more than 48 hours straight, but sometimes, usually when the PSU has been off for some time the CANbus nodes behaves strangely. After a couple of quick restarts of the PSU the nodes start communicating reliably. Only sometimes one of them gives up on communication.
Some thoughts: Maybe it is not OK to set some bits through the code composer studio directly in the ECanaRegs register and this is why I might get the CCE bit set unexpectedly, but when JTAG is disconnected I can observe the same behaviour.
The design is a copy of the respective Launchpad and I'm using the same CAN transceiver.
Here is my initialisation code if it matters:
void InitECana(void) // Initialize eCAN-A module
{
/* Create a shadow register structure for the CAN control registers. This is
needed, since only 32-bit access is allowed to these registers. 16-bit access
to these registers could potentially corrupt the register contents or return
false data. */
struct ECAN_REGS ECanaShadow;
EALLOW; // EALLOW enables access to protected bits
/* Configure eCAN RX and TX pins for CAN operation using eCAN regs*/
ECanaShadow.CANTIOC.all = ECanaRegs.CANTIOC.all;
ECanaShadow.CANTIOC.bit.TXFUNC = 1;
ECanaRegs.CANTIOC.all = ECanaShadow.CANTIOC.all;
ECanaShadow.CANRIOC.all = ECanaRegs.CANRIOC.all;
ECanaShadow.CANRIOC.bit.RXFUNC = 1;
ECanaRegs.CANRIOC.all = ECanaShadow.CANRIOC.all;
/* Configure bit timing parameters for eCANA*/
ECanaShadow.CANMC.all = ECanaRegs.CANMC.all;
ECanaShadow.CANMC.bit.CCR = 1 ; // Set CCR = 1
ECanaRegs.CANMC.all = ECanaShadow.CANMC.all;
// Wait until the CPU has been granted permission to change the configuration registers
do
{
ECanaShadow.CANES.all = ECanaRegs.CANES.all;
} while(ECanaShadow.CANES.bit.CCE != 1 ); // Wait for CCE bit to be set..
ECanaShadow.CANBTC.all = 0;
//500Kbit
ECanaShadow.CANBTC.bit.BRPREG = 9;
ECanaShadow.CANBTC.bit.TSEG1REG = 14;
ECanaShadow.CANBTC.bit.TSEG2REG = 1;
// 125Kbit
//ECanaShadow.CANBTC.bit.BRPREG = 39;
//ECanaShadow.CANBTC.bit.TSEG1REG = 14;
//ECanaShadow.CANBTC.bit.TSEG2REG = 1;
//ECanaShadow.CANBTC.bit.SAM = 1;
ECanaRegs.CANBTC.all = ECanaShadow.CANBTC.all;
ECanaShadow.CANMC.all = ECanaRegs.CANMC.all;
// Clear some bits first
ECanaShadow.CANMC.bit.CCR = 0;
ECanaShadow.CANMC.bit.PDR = 0;
ECanaShadow.CANMC.bit.DBO = 0;
ECanaShadow.CANMC.bit.WUBA = 0;
ECanaShadow.CANMC.bit.CDR = 0;
ECanaShadow.CANMC.bit.ABO = 0;
ECanaShadow.CANMC.bit.STM = 0;
ECanaShadow.CANMC.bit.SRES = 0;
ECanaShadow.CANMC.bit.MBNR = 0;
// self-test mode
//ECanaShadow.CANMC.bit.STM = 1;
// Enable HECC mode
ECanaShadow.CANMC.bit.SCB = 1;
ECanaRegs.CANMC.all = ECanaShadow.CANMC.all;
/* Initialize all bits of 'Message Control Register' to zero */
// Some bits of MSGCTRL register come up in an unknown state. For proper operation,
// all bits (including reserved bits) of MSGCTRL must be initialized to zero
ECanaMboxes.MBOX0.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX1.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX2.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX3.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX4.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX5.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX6.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX7.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX8.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX9.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX10.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX11.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX12.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX13.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX14.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX15.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX16.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX17.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX18.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX19.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX20.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX21.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX22.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX23.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX24.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX25.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX26.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX27.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX28.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX29.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX30.MSGCTRL.all = 0x00000000;
ECanaMboxes.MBOX31.MSGCTRL.all = 0x00000000;
// Wait until the CPU no longer has permission to change the configuration registers
do
{
ECanaShadow.CANES.all = ECanaRegs.CANES.all;
} while(ECanaShadow.CANES.bit.CCE != 0 ); // Wait for CCE bit to be cleared..
// TAn, RMPn, GIFn bits are all zero upon reset and are cleared again
// as a matter of precaution.
ECanaRegs.CANTA.all = 0xFFFFFFFF; /* Clear all TAn bits */
ECanaRegs.CANRMP.all = 0xFFFFFFFF; /* Clear all RMPn bits */
ECanaRegs.CANGIF0.all = 0xFFFFFFFF; /* Clear all interrupt flag bits */
ECanaRegs.CANGIF1.all = 0xFFFFFFFF;
/* Disable all Mailboxes */
ECanaRegs.CANME.all = 0; // Required before writing the MSGIDs
EDIS;
}I'm not using any interrupts. This is working in combination with Motorware and InstaspinMotion. The can mailboxes are read in the mainISR at the frequency of the mainloop - in my case - 15Khz. And I transmit at 3Hz rate.
This is how I transmit messages:
ECanaShadow.CANTA.all = ECanaRegs.CANTA.all;
// Wait for all TAn bits to be set..
if (msgPending && msgAck == false && ECanaShadow.CANTA.bit.TA1 == 1) {
ECanaShadow.CANTA.bit.TA1 = 1;
msgAck = true;
}
if (msgPending && msgAck && ECanaShadow.CANTA.bit.TA1 == 0) {
msgPending = false;
//msgAck = true;
}
ECanaRegs.CANTA.all = ECanaShadow.CANTA.all;
if (msgPending == false) {
ECanaMboxes.MBOX1.MDL.all = values.i_value;
ECanaMboxes.MBOX1.MDH.all = USER_ID;
// Set transmission flag
ECanaShadow.CANTRS.all = ECanaRegs.CANTRS.all;
ECanaShadow.CANTRS.bit.TRS1 = 1;
ECanaRegs.CANTRS.all = ECanaShadow.CANTRS.all;
msgPending = true;
msgAck = false;
MessageSentCount++;
}
