CCS/TMDSCNCD280049C: What is the proper setup for external CAN signals to see?

I am using sn65hvd251 for CAN transeiver. this works fine when i use can_ex1_loopback both at CANTXA pin GPIO31 and after CAN transeiver.

Are you saying you are able to see the waveform with can_ex1_loopback but not with can_ex3_external_transmit? Can you post the waveforms?

Have you looked at SPRACE5? Specifically section 4.1 where I have explained how to configure the correct GPIO pins?

This is same problem with LAUNCHXL-F280049C in ticket: e2e.ti.com/.../787271 , which is not solved.

That post was closed due to lack of response from the original poster. We cannot solve a problem if we don’t hear back after our suggestions/debug tips.

Hi Hareesh,

the waveforms are like this at tx pin(gpio31)

i am able to see the frames in canalyser while using can_ex1_loopback. 

I dont see the same while using can_ex3_external_transmit.

BTW i looked into SPRACE5 sec 4.1. As per that i am using TMDSCNCD28004x_RevA_120cCARD_pinout.pdf for matching GPIO.

Thank you

Lakshmi

The fact that you are able to see the frames in canalyser while using can_ex1_loopback tells me that there are likely no H/W issues. For this specific testcase, are you able to see the ACK from the CANalyzer on the CANRX pin? That is the proof that the H/W path is good from start to finish. The mere appearance of frames on the analyzer cannot be construed as proof for this, since the CAN module is not really looking for an external ACK, being a self-test case. Please provide the waveform for both CANTX & CANRX pins. I would like to verify if the ACK signal is received in CANRX pin. The waveform that you capture should be exactly identical to Fig 4 in SPRACE5. 

BTW i looked into SPRACE5 sec 4.1. As per that i am using TMDSCNCD28004x_RevA_120cCARD_pinout.pdf for matching GPIO.

I don’t understand what you are trying to convey with the above statement. Section 4.1 does not refer to any particular H/W. It only talks about choosing the correct GPIO pins for CAN operation based on your H/W.

Hello Hareesh,

• This is my Connnection 

• There is no signal at RX pin
• The signal in yellow is Tx-Gnd and Blue is CAN_H vs CAN_L

• BTW i looked into SPRACE5 sec 4.1. As per that i am using TMDSCNCD28004x_RevA_120cCARD_pinout.pdf for matching GPIO.

Last point i wanted to conway was i have connected properly. 

Regards

LT

Which version of C2000ware are you using?

For can_ex1_loopback example (for which you confirmed you are able to see the signal on CANA_TX-GPIO31 pin), are you able to see the same signal in CANA_RX-GPIO30 pin)? If not, there is some H/W issue on your setup that you need to debug first.

Can you try the can_ex4_simple_transmit.c example in C:\ti\c2000\C2000Ware_2_00_00_03\driverlib\f2837xd\examples\cpu1\can? Though written for 2837x, it should be easy to port it for 280049.

Did you go through the Debug tips in SPRACE5 (section 3)?

Dear Hareesh,

1. I have gone through Debug tips.
2. I am using the lastest version of C2000ware
3. I am able to see on GPIO 31 but not GPIO 30 when using can_ex1_loopback.

4. I checked can_ex4_simple_transmit.c to port it. 

The errorFlag is set to 1 and status is set to 0x000000E5

Regards

LT

1. I am able to see on GPIO 31 but not GPIO 30 when using can_ex1_loopback.

You absolutely need to figure this out first before doing anything else. The CANRX pin activity must be exactly identical to CANTX pin with the exception of arbitration & ACK field (see Fig 4 in SPRACE5). Until you resolve this, it is pointless trying anything else. 

2. I checked can_ex4_simple_transmit.c to port it. 

The porting should be fairly straightforward. 

The errorFlag is set to 1 and status is set to 0x000000E5

It appears node is in bus-off.

Hi Hareesh,

This is the signal i am getting on GPIO 31 Tx and CAN_L vs CAN_H.

As clearly indicated (twice) in my previous posts, I need to see the signal on the CANRX pin, not CAN_H & CAN_L lines. Until you resolve this H/W issue at your end, I regret I cannot help further.