TMS320F28388D: using CM core for CAN Communication

Hi Swapnil,

We'll have our DCAN expert to look into this in detail but wanted to check one quick thing - By default CANx modules are assigned to CPU1 and you need to configure PALLOCATE register bit (refer "Table 3-43. PALLOCATE0 Register Field Descriptions" in TRM) to assign this IP to CM. This need to be done by CPU1 code only. Please if you are doing this already.

Regards,

Vivek Singh

Hi Vivek,

Thank you for reply. 

yes, I am doing that already. 

    //
    // Allocate Shared Peripheral CAN A to the CM Side.
    //
    SysCtl_disablePeripheral(SYSCTL_PERIPH_CLK_CANA);
    SysCtl_allocateSharedPeripheral(SYSCTL_PALLOCATE_CAN_A,0x1U);
    SysCtl_enablePeripheral(SYSCTL_PERIPH_CLK_CANA);

I have also looked at the CmConfgRegs to verify it the bit is set for CAN_A peripheral. 

Swapnil

Good. Thank you. Our Can expert will get back to you.

Regards,

Vivek Singh

Hi Swapnil,

I am assuming that you used the CAN_ex3_transmit in the cm example folder.  I think what is missing is the configuration of the CAN pins.  If you look at the c28 example, you have these lines of code:

    //
    // Initialize GPIO and configure GPIO pins for CANTX/CANRX
    // on module A and B
    //
    Device_initGPIO();
    GPIO_setPinConfig(DEVICE_GPIO_CFG_CANRXA);
    GPIO_setPinConfig(DEVICE_GPIO_CFG_CANTXA);
    GPIO_setPinConfig(DEVICE_GPIO_CFG_CANRXB);
    GPIO_setPinConfig(DEVICE_GPIO_CFG_CANTXB);

For whatever DCAN module you are using, can you run this code in c28 first to ensure that the CAN pins are mapped before running the transmit pattern in cm?

Regards,

Joseph

Hi Joseph, 

Thank you for your response! 

This is my setup code on C28X side. 

    //
    // Configuring the GPIOs for CAN A.
    //
    GPIO_setPinConfig(DEVICE_GPIO_CFG_CANRXA);
    GPIO_setPinConfig(DEVICE_GPIO_CFG_CANTXA);

    //
    // Allocate Shared Peripheral CAN A to the CM Side.
    //
    SysCtl_disablePeripheral(SYSCTL_PERIPH_CLK_CANA);
    SysCtl_allocateSharedPeripheral(SYSCTL_PALLOCATE_CAN_A,0x1U);
    SysCtl_enablePeripheral(SYSCTL_PERIPH_CLK_CANA);

and my pinmux is configured as, 

//
// CANA
//
#define DEVICE_GPIO_PIN_CANTXA      4U  // GPIO number for CANTXA
#define DEVICE_GPIO_PIN_CANRXA      5U  // GPIO number for CANRXA

#define DEVICE_GPIO_CFG_CANRXA      GPIO_5_CANRXA  // "pinConfig" for CANA RX
#define DEVICE_GPIO_CFG_CANTXA      GPIO_4_CANTXA  // "pinConfig" for CANA TX

Swapnil

Hi Swapnil,

Ok, looks like you have taken care of this in your code.  What external CAN logger do you use, PCAN?  Does the logger display the CAN frame that was last transmitted?  Just trying to understand if the error status in CAN_ES is a result of missing ACKnowledge signal.  If you use PCAN, I think it has a feature to send an ACK signal to the transmitting node.

 Regards,

Joseph

Hi,

I am using Kvaser Memorator PRo 2xHS v2 which has feature to send same ACK signal. 

When I ran the only C28x version from the example codes, I had no problem seeing it on CANLab. 

I have exported CAN register information with CAN running on C28x and on CM core. I have attached that if that helps. 

CAN_register_info.xlsx

Hi Swapnil,

Yes, the CAN register dumps would help a lot.  Unfortunately, I may have to try this out on my setup to see if I can duplicate what you are seeing.  I do not have immediate access to a F2838x setup because of the prevailing conditions but I can work this out and may take me a day.  In the meantime, I will go through the register dumps you sent and see if there is any outstanding issues I see on the CM dumps...

Regards,

Joseph

Hi Joesph,

Thank you for your help. I look forward to hearing from you.

Swapnil

Hi Swapnil,

I had a chance to do a quick validation on my setup, however i do not have an access to an external CAN logger similar to what you are using.  On the C28 side, I  enabled the CAN GPIO pins using exactly what you have (GPIO5 for RX and GPIO4 for TX), assigned CANA to CM and on the CM side, I ran the can_ex3 example without the receive and ISR functions.  I have an access to a scope that is able to decode DCAN frames so that is what I am using to observe the signals in the CANTX pin and the CAN bus.

I am able to observe the correct CAN frame on the TX pin as well as on the CAN bus.  CANA is set to 500Kbps and payload is set to 4 bytes as in the example.  Here is the scope capture of the can transmit code initiated from CM side:

Not sure why your CAN logger is not able to detect the CAN frames that are initiated on the CM side.  Do you have an access to a scope to see if you can observe the signals coming out of the CAN pins?

Regards,

Joseph

Hi Joseph,

Unfortunately I do not have access to the scope right now because of current situation. I will check with a scope as soon as I can get back to the office and get back to you.

Thank you for your help again.

Swapnil