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Tester Present Problem in PCAN UDS

Posted: Thu 20. Aug 2020, 12:05
by Shail
Hello,

I am using the PCAN UDS API testDiagnosticSessionControl to send ECU to boot mode.

1) In the sample code of C++ PCAN UDS API where the tester present request send since we are not able to find any specific function which sending tester present?
printf(" Assert that Auto TesterPresent Frame is sent...\n");
Sleep(2000);
printf(" Should transmit an Auto TesterPresent Frame\n");

We do not want to use programming request to send ECU in boot mode but the problem is in programming request only tester present request is send.
2) If we do not want to use diagnostic request how we can send tester present service cyclically to make session alive? Should we can send dummy positive response of tester present from ECU to work?

3) Due to absent of tester present security service is not working. How to handle this to scenario?

Thanks in advance.

Re: Tester Present Problem in PCAN UDS

Posted: Thu 20. Aug 2020, 15:06
by K.Wagner
Hello,
Shail wrote:
Thu 20. Aug 2020, 12:05
1) In the sample code of C++ PCAN UDS API where the tester present request send since we are not able to find any specific function which sending tester present?
Note that entering a session other than the default (DSC_DS) activates an automatic mechanism designed to keep alive non-default diagnostic sessions without interaction of the user. This is part of the specifications and It is not possible to change this behavior.
Shail wrote:
Thu 20. Aug 2020, 12:05
2) If we do not want to use diagnostic request how we can send tester present service cyclically to make session alive? Should we can send dummy positive response of tester present from ECU to work?
you can use the function SvcTesterPresent within a default session, using a thread or a timer to do this periodically. Check the UDS documentation on page 153 for more information on SvcTesterPresent.
Shail wrote:
Thu 20. Aug 2020, 12:05
3) Due to absent of tester present security service is not working. How to handle this to scenario?
Send the TesterPresent for your own as described in point 2.

Re: Tester Present Problem in PCAN UDS

Posted: Thu 20. Aug 2020, 15:55
by K.Wagner
Hello,

regarding my answer on TesterPresent:
K.Wagner wrote:
Thu 20. Aug 2020, 15:06
Note that entering a session other than the default (DSC_DS) activates an automatic mechanism designed to keep alive non-default diagnostic sessions without interaction of the user. This is part of the specifications and It is not possible to change this behavior.
It is indeed possible to suppress the TesterPresent automatic sending on non-default sessions. You need to change the UDS session information using the function SetValue to be of type DSC_DS. This change affects only the API client, not the ECU. You will find an example on page 93 of the UDS documentation.

Thanks to F.Vergnaud for bringing this to my attention.