topic MPC5748G chip reset in MPC5xxx

MPC5748G chip reset

VVolk — Tue, 27 Jul 2021 23:15:17 GMT

Hello, I have problem, just set password for MPC5748G (JTAG). And now can not reset. How I can resell all information and password on this MPC5748G?

Re: MPC5748G chip reset

petervlna — Wed, 28 Jul 2021 08:19:37 GMT

Hello,

Could you be more specific?

Which steps you take to set password? Are you talking about censorship (JTAG passwords) ?

Best regards,

Peter

Re: MPC5748G chip reset

VVolk — Wed, 28 Jul 2021 15:55:20 GMT

Hello Peter, thanks for a quick response.

I try turn on password on Utest flash in pmicro. So I need reset all flash now. How do to that? Because it's not possible reset just password?!

Re: MPC5748G chip reset

petervlna — Thu, 29 Jul 2021 08:54:18 GMT

Hello,

UTEST is one time programmable memory. And Passwords are write only once. So you cant erase them once programmed from security reasons.

However if you know your passwords and are able to connect to micro, then you can add another censorship DCF record to disable censorship protection mechanism.

Censoring the device is delicate process, which require full understanding of censoring scheme before any programming. Otherwise you can esily brick the device.

Are you able to connect to the micro?

Best regards,
Peter

Re: MPC5748G chip reset

VVolk — Thu, 29 Jul 2021 20:23:05 GMT

Hello

I can not connect

So I need to change it for new one ?

Thank you!

Re: MPC5748G chip reset

petervlna — Fri, 30 Jul 2021 07:10:59 GMT

Hello,

Hmm, so you program the JTAG password and once you enter the password to debugger you cannot connect. Correct?

So you either forgot the password, or did not follow the procedure correctly.

One more thing comes to my mind is that you did not take care of SWT which will reset device after 20ms after reset and disconnect debugger.

Did you had any SW taking care of SWT in device when you censored it?

Best regards,

Peter

Re: MPC5748G chip reset

VVolk — Sun, 01 Aug 2021 23:37:47 GMT

Hello, Peter

Device working correctly, I want to do full reset ... And set everything like for new

Best regards!

Re: MPC5748G chip reset

petervlna — Tue, 03 Aug 2021 06:06:50 GMT

Hello,

Unfortunately this is not possible to achieve as the UTEST is one time programmable (OTP). So no erase is possible.

That you can do is to add new censorship DCF record where you disable censorship.

Best regards,

Peter