Re: Problem receiving > 8 byte UDS response when using istpsend

[Andre Naujoks <nautsch2@gmail.com>]

Am 21.11.22 um 13:08 schrieb Marvin Ludersdorfer:
> Hi,
> 
> I'm experiencing problems when trying to read out ECU parameters using istpsend when the response exceeds 8 bytes:
> 
> In one terminal, I run isotpdump -s 00000680 -d 00000780 -c -ta can0

Use isotprecv instead of isotpdump. isotpsend just sends the 3 bytes, 
you pass to it and then is done.

The FC should then be sent by the socket, which is opened by isotprecv.

E.g.
terminal 1: isotprecv -s 00000680 -d 00000780 vcan0  <anything else>
terminal 2: echo 22 f1 95 | isotpsend -s 00000680 -d 00000780 vcan0 
<anything else>

... your milage may vary though.

Regards
   Andre

> 
> In another terminal, I run echo 22 F1 95 | isotpsend -s 00000680 -d 00000780 can0 -p 0x00
> 
> In the first terminal, I receive only the FF, but no FC frame is sent (expected is a 11-byte response).
> 
> If I turn around the communication direction and run isotpsend -s 00000680 -d 0000780 can0 -D 255, the target ECU answers correctly by sending the expected FC frame.
> 
> 
> I would expect that isotpsend takes care of sending the FC frame in the first example as well to receive the full response - am I doing something wrong?
> 
> Any help would be highly appreciated!
> 
> Best regards,
> 
> Marvin Ludersdorfer
>