TMS320F28335: f28335 ecan example rx/tx not output

user5913644

Part Number: TMS320F28335
Other Parts Discussed in Thread: SN65HVD232

i use example ecana_to_b_xmit . i just want to see rx tx signal but don't have any signal line even i used SN65HVD232 to change can signal . is it tx/rx a tinny signal ?

or did i Modify correct program?

another question i don't know how to check SN65HVD232 which normal or broken?

over 6 years ago

0 Hareesh Janakiraman over 6 years ago

TI__Guru* 95315 points

The resolution of the circuit diagram you attached is very poor. Besides, there is not a whole lot of detail in it for me to make any meaningful debug. Please attach the complete schematics (or at least the CAN signals from the DSP all the way to the bus).

What do Q6, Q7 & Q8 do?

What does R5 do? Why do you need a resistor in the supply line?

Have you checked the Debug tips in http://www.ti.com/lit/spra876 ?

0 Hareesh Janakiraman over 6 years ago in reply to Hareesh Janakiraman

TI__Guru* 95315 points

Please clarify what you mean by "tinny signal"

0 user5913644 over 6 years ago in reply to Hareesh Janakiraman

Prodigy 205 points

is rx/tx signal too small to catch?

0 user5913644 over 6 years ago in reply to Hareesh Janakiraman

Prodigy 205 points

q5~q8 just a i optical coupler

r5 r6 is 5v change to 3.3v

i confused why rx/tx signal i can't measure

0 Hareesh Janakiraman over 6 years ago in reply to user5913644

TI__Guru* 95315 points

CANTX signal level is 3.3v. You definitely should be able to measure it with a scope.

You should not use resistors on the supply line, which could potentially current-starve a device. You need to generate 3.3v for the transceiver or use 5v transceivers (after ensuring you don't violate VIH spec of the MCU).

It is likely there is some issue with your circuitry. Please refer to the Launchpad schematics that show proper connection for CAN.

0 user5913644 over 6 years ago in reply to Hareesh Janakiraman

Prodigy 205 points

i find the answer because i used too long

Dupont Line had a lot interference

0 Hareesh Janakiraman over 6 years ago in reply to user5913644

TI__Guru* 95315 points

OK, thanks for letting us know. Next time, when an issue is resolved, please close the post.

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TMS320F28335: f28335 ecan example rx/tx not output