topic Re: Unsecure S12ZVC in S12 / MagniV Microcontrollers

Unsecure S12ZVC

yuntianlu — Wed, 23 Dec 2015 00:27:36 GMT

Hello, All

I am having trouble to unsecure S12ZVC controller using the ERASE_FLASH (0x95/d) command in BDC.

I tried ERASE_FLASH command on both secured and unsecured controllers, it doesn't work. The command was issued on BKGD pin through FPGA.

I am able to read the FSTAT register on unsecured controllers. The error flag ACCER in the FSTAT is set after ERASE_FLASH command is issued. Not sure if that is the reason. Not able to read the FSTAT register on secured controllers.

Any suggestion or code sample will be helpful.

Thank you

Re: Unsecure S12ZVC

RadekS — Tue, 29 Dec 2015 23:25:03 GMT

Hi yuntianlu,

Unfortunately I don’t have direct experience with ERASE_FLASH command. However chapter 3.4.4.19 ERASE_FLASH in RM mentioned several conditions:

This command must be sending twice in succession. Delay between these commands must be longer than 16 clock cycles (DLY) and shorter than 512 BDCSI clock cycles.
No ACK pulse is generated.
MCU must run on default clock settings (bus clock = 6.25MHz).
After calling ERASE_FLASH command we have to check BDCCSR_ERASE bit in wait loop until erase/unsecure finished.

I hope it helps you.

Have a great day,
RadekS

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Re: Unsecure S12ZVC

yuntianlu — Wed, 30 Dec 2015 01:16:07 GMT

Hello, RadekS

Thank you for the response.

I think my problem is the relay bounce at power up. Once I had a power on delay, everything works.

Have a great day,

Re: Unsecure S12ZVC

RadekS — Wed, 30 Dec 2015 07:42:48 GMT

Hi yuntianlu,

Thank you for let us know the result.

I am glad that it works now.

Best Regards

RdekS