topic Re: P89LPC922 Security bits in 8-bit Microcontrollers

P89LPC922 Security bits

rafal_obirek — Fri, 29 May 2020 22:11:49 GMT

Hi everybody,

I have microcontroller LPC922 and he has some sectors locked with security bits ( 0x07 ).

In the documentation is written ( as I understood ) that "global erase" shall clear these bits with 0x00 ( parallel programmer )

http://www.keil.com/dd/docs/datashts/philips/ps_900.pdf

I bought a programmer TOP2013 and during ERASE I have observed with logic analyzer what is written to.

As I expected there was written 0x72 order to FMCON register and than is few reads from FMCON to check if programming was successor not. This checking takes around 4ms and status is always F0 what tells that chip is BUSY ( probably erasing is in progress ). But programmer doesn't wait until the status is 0x70 and breaks VCC and return SUCCESS.

Later after reading security bits is still the same and nothing changes.

Writing 0x07 to other sectors which were 0x00 before works perfectly, but restoring it back by global erase not.

And my question is now :

1. When security bits for given sector is already 0x07 is it possible to restore it back with 0x00 via global erase at all?

2. How long can take the execution of GLOBAL ERASE for this chip ?

Regards

Rafael

Re: P89LPC922 Security bits

rafal_obirek — Mon, 01 Jun 2020 20:51:12 GMT

Update from yesterday :

I tok Nucleo board and I have generated sequence to send "global erase". Status was changed from BUSY to READY after around 7ms. Security bits were succesfully erased. That means it is a bug in programmer or programmer application TopAll8. After erasing all my microcontrollers with Nucleo board, I was able to program bootloader using TOP2013 and then access to uC via ISP. Everything works now.

Re: P89LPC922 Security bits

jacekgałuszczyń — Mon, 06 Jul 2020 22:02:42 GMT

Witam,czy mógłbyś udostępnić kod do Nucleo na global erase?

Pozdrawiam,

JacekG

Re: P89LPC922 Security bits

rafal_obirek — Tue, 07 Jul 2020 03:47:18 GMT

Hej.

Teraz jestem na urlopie do 28 lipca więc nie mam możliwości.

Ale jak wrócę to się podzielę. Wszystko chyba jest jako projekt w środowisku Cube. Spakuję i wyślę całość. Mogę dodatkowo dać bootloader do poprawnego działania isp.

Ustawiłem sobie przypomnienie na telefonie to nie zapomnę.

Regards/MfG/Pozdrawiam

Rafal Obirek

Re: P89LPC922 Security bits

jacekgałuszczyń — Tue, 07 Jul 2020 07:22:29 GMT

Dzięki, miłego urlopu.

Re: P89LPC922 Security bits

rafal_obirek — Tue, 28 Jul 2020 13:14:40 GMT

Wrzuciłem wszystko tutaj : GitHub - kociejsko/lpc922_erase_Nucleo