MPC5748G chip reset

[VVolk]

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?

[petervlna]

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

[VVolk]

Hello

I can not connect

So I need to change it for new one ?

Thank you!

[petervlna]

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

[VVolk]

Hello, Peter

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

Best regards!

[petervlna]

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

[petervlna]

Hello,

Could you be more specific?

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

Best regards,

Peter

[VVolk]

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?!