eCan transmit problem

Hi Masky,

Do the examples files work or not?

Regards,

Gautam

Hi Gautan,

nop, the programme is always running in the do/while loop, waiting for TA to be set. 

                    ECanaShadow.CANTRS.all = 0;

                    ECanaShadow.CANTRS.bit.TRS25 = 1;     // Set TRS for mailbox under test
                    ECanaRegs.CANTRS.all = ECanaShadow.CANTRS.all;

                    do
                    {
                          ECanaShadow.CANTA.all = ECanaRegs.CANTA.all;
                    } while(ECanaShadow.CANTA.bit.TA25 == 0 );   // Wait for TA bit to be set..

Hi,

Something seems to be missing here! The example code does work fine... Can you please check with the loopback connections?

Regards,

Gautam

Hello Gautam,

I disconnected pin 7 (CANTXA) and CAN transceiver, and I got the signal with the oscilloscope. Now I have 3V, but any frames is sent. So....maybe there is something in the wrong in the initialization? The code is as follow:

void InitECanaGpio(void)

{

GpioCtrlRegs.GPAPUD.bit.GPIO30 = 0; // Enable pull-up for GPIO30 (CANRXA)
GpioCtrlRegs.GPAPUD.bit.GPIO31 = 0; // Enable pull-up for GPIO31 (CANTXA)
GpioCtrlRegs.GPAQSEL2.bit.GPIO30 = 3; // Asynch qual for GPIO30 (CANRXA)
GpioCtrlRegs.GPAMUX2.bit.GPIO30 = 1; // Configure GPIO30 for CANTXA operation
GpioCtrlRegs.GPAMUX2.bit.GPIO31 = 1; // Configure GPIO31 for CANRXA operation

}

void InitECana(void) // Initialize eCAN-A module
{
long i;

EALLOW; // EALLOW enables access to protected bits

/* Configure eCAN RX and TX pins for eCAN transmissions 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 eCAN for HECC mode - (reqd to access mailboxes 16 thru 31) */
// HECC mode also enables time-stamping feature

ECanaShadow.CANMC.all = ECanaRegs.CANMC.all;
ECanaShadow.CANMC.bit.SCB = 1;
ECanaRegs.CANMC.all = ECanaShadow.CANMC.all;

/* Initialize all bits of 'Master Control Field' 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;

// 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;

/* 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;

while(ECanaRegs.CANES.bit.CCE != 1 ) {} // Wait for CCE bit to be set..

ECanaShadow.CANBTC.all = 0;
// ECanaShadow.CANBTC.bit.BRPREG = 9;
ECanaShadow.CANBTC.bit.BRPREG = 19; // para SYSCLKOUT = 20 ns => 1/(20 Mhz *5 /2) BRP+1 =20
ECanaShadow.CANBTC.bit.TSEG2REG = 1;
ECanaShadow.CANBTC.bit.TSEG1REG = 6;
ECanaShadow.CANBTC.bit.SAM = 1;
ECanaRegs.CANBTC.all = ECanaShadow.CANBTC.all;

ECanaShadow.CANMC.all = ECanaRegs.CANMC.all;
ECanaShadow.CANMC.bit.CCR = 0 ; // Set CCR = 0
ECanaRegs.CANMC.all = ECanaShadow.CANMC.all;

while(ECanaRegs.CANES.bit.CCE == !0 ) {} // Wait for CCE bit to be cleared..

/* Disable all Mailboxes */
ECanaRegs.CANME.all = 0; // Required before writing the MSGIDs

EDIS;

/* Write to the MSGID field */

ECanaMboxes.MBOX25.MSGID.all = 0x00000700; // 0x700 <<10

/* Configure Mailbox 25 as a Transmit mailbox and 20 as a receive*/

ECanaShadow.CANMD.all = ECanaRegs.CANMD.all;
ECanaShadow.CANMD.bit.MD25 = 0;
ECanaShadow.CANMD.bit.MD20 = 1;
ECanaRegs.CANMD.all = ECanaShadow.CANMD.all;

/* Enable Mailbox under test */

ECanaShadow.CANME.all = ECanaRegs.CANME.all;
ECanaShadow.CANME.bit.ME25 = 1;
ECanaShadow.CANME.bit.ME20 = 1;
ECanaRegs.CANME.all = ECanaShadow.CANME.all;

/* Write to DLC field in Master Control reg */

ECanaMboxes.MBOX25.MSGCTRL.bit.DLC = 8;

/* Write to the mailbox RAM field */

ECanaMboxes.MBOX25.MDL.all = 0x55555555;
ECanaMboxes.MBOX25.MDH.all = 0x55555555;

// Since this write is to the entire register (instead of a bit
// field) a shadow register is not required.
EALLOW;
ECanaRegs.CANMIM.all = 0xFFFFFFFF;

// Configure the eCAN for self test mode
// Enable the enhanced features of the eCAN.
EALLOW;
ECanaShadow.CANMC.all = ECanaRegs.CANMC.all;
ECanaShadow.CANMC.bit.STM = 1; // Configure CAN for self-test mode
ECanaRegs.CANMC.all = ECanaShadow.CANMC.all;
EDIS;

/* Begin transmitting */


for(i=0; i < 3;)
{
ECanaShadow.CANTRS.all = 0;
ECanaShadow.CANTRS.bit.TRS25 = 1; // Set TRS for mailbox under test
ECanaRegs.CANTRS.all = ECanaShadow.CANTRS.all;

while(ECanaRegs.CANTA.bit.TA25 == 0 ) {} // Wait for TA5 bit to be set..

ECanaShadow.CANTA.all = 0;
ECanaShadow.CANTA.bit.TA25 = 1; // Clear TA5
ECanaRegs.CANTA.all = ECanaShadow.CANTA.all;

// loopcount ++;
}

}

P.D: sorry, but I didn't understand the meaning of loopback (I think in spanish there isn't a translation for this).

Thank you.

Hi,

Loop back connection means connect CANTXA -> CANRXA; and then checking values of CANRXA whether it matches with the transmitted data or not!

Regards,

Gautam

Hello Gautam,

I did this, but I can't receive anything. I always get a stuff bit error, Maybe this depends on how TSEG1 & TSEG2 are configured?

Hi Masky,

But then the sample code is enough for this loopback test, you must not face an issue here. I guess only the documentation would shed some light to your problem.

Regards,

Gautam

Hi Masky,

Both MBOX20 and 25 must be configured with the same Message ID. Looks like you have configured only MBOX25 but have forgotten to configure MBOX20with the same message ID.

ECanaMboxes.MBOX25.MSGID.all = 0x00000700; // 0x700 <<10         // Done

ECanaMboxes.MBOX20.MSGID.all = 0x00000700; // 0x700 <<10        // Forgotten

Thanks,

Vivek