TMS570LS3137: TMS570LS3137 Hercules Launchpad CAN3 output problem.

Cevdet CIVIR

Part Number: TMS570LS3137
Other Parts Discussed in Thread: HALCOGEN,

Hi,

I wanted to send data via CAN1 CAN2 and CAN3 pins on Hercules Launchpad. I can send data from CAN1 and CAN2 pins properly with the "canTransmit()" command. But I could not observe the data I wanted to send over CAN3 pins with the logic analyzer. Is there a specific reason for this?

I can observe the data I want to send with the logic analyzer through the J2(DCAN1) and J3(DCAN2) terminal blocks on the Launchpad. At the same time, I read the data I want to send over the CAN1 and CAN2 pins on the J11 connector with the logic analyzer.

But when I wanted to send data over the "CAN3TX" pin on the J11 connector, I was not successful.

Best Regards.

over 2 years ago

0 QJ Wang over 2 years ago

TI__Guru**** 186256 points

Have you enabled CAN3 module?

I tried TX data on CAN3_TX pin, and saw the transmitted data on Pin 12 (CAN3_TX) of J11.

0 QJ Wang over 2 years ago in reply to QJ Wang

TI__Guru**** 186256 points

BTW, I think that the board you are using is HDK rather than launchpad.

0 Cevdet CIVIR over 2 years ago in reply to QJ Wang

Prodigy 70 points

Here you can see my Halcogen Configuration. Is there any mistake ?

My tx_ data is;

#define D_SIZE 8

uint8_t tx_data[D_SIZE] = {'a', 'b', 'c', 'd', 'e', 'f', 'g', 'g'};

I am using CAN3 Port, MessageBox 2

canTransmit(canREG3, canMESSAGE_BOX2, tx_data);

0 QJ Wang over 2 years ago in reply to Cevdet CIVIR

TI__Guru**** 186256 points

The configuration is correct.

I used the same configuration, and got the transmitted data on CAN bus:

There are only 2 CAN transceivers on HDK, and they are connected to DCAN1 and DCAN2. To test DCAN3, please connect pin 9 and pin 11, and connect pin 12 and pin 10 of J11, so the DCAN3 can use the DCAN transceiver on the HDK. Please disable CAN2 as well.

0 Cevdet CIVIR over 2 years ago in reply to QJ Wang

Prodigy 70 points

QJ Wang said:
There are only 2 CAN transceivers on HDK, and they are connected to DCAN1 and DCAN2. To test DCAN3, please connect pin 9 and pin 11, and connect pin 12 and pin 10 of J11, so the DCAN3 can use the DCAN transceiver on the HDK. Please disable CAN2 as well.

This solution worked. But I am wondering, I am using TMS570LS3137 MCU. Doesn't this MCU support CANBUS communication without CAN BUS transceiver? Under normal circumstances, don't I need to receive data from CAN3TX and CAN3RX pins without a CANBUS transceiver?

0 QJ Wang over 2 years ago in reply to Cevdet CIVIR

TI__Guru**** 186256 points

Please refer to this thread for CAN BUS communication without CAN transceiver:

https://e2e.ti.com/support/microcontrollers/arm-based-microcontrollers-group/arm-based-microcontrollers/f/arm-based-microcontrollers-forum/876831/tms570lc4357-tms570lc4357-without-can-transceiver-try-to-connect-the-can-bus-of-tms570lc4357

Arm-based microcontrollers

Arm-based microcontrollers forum

TMS570LS3137: TMS570LS3137 Hercules Launchpad CAN3 output problem.