topic Re: LPC5528 Simple CRP enable/disable in LPC Microcontrollers

LPC5528 Simple CRP enable/disable

bressan — Tue, 26 Apr 2022 08:14:11 GMT

I want to write a simple code read protection for LPC5528, which can be enabled/disabled via USB.

Until now, I have only LPC55S28.

Afraid of bricking the device, I tried writing in customer area first.

I tried writing on a LPC55S28 via FFR this way:

DisableIRQ(); setcpu100MHz(); Status = FLASH_Init(&flashInstance); //returns 0 Status = FFR_Init(&flashInstance); //returns 0=ok FLASH_GetProperty(&flashInstance, kFLASH_PropertyPflashPageSize, &PflashPageSize); Status = FFR_InfieldPageWrite(&flashInstance, iap_FlashRam, len); //returns 0x64. why?

iap_flashram contains a copy of the 0x09df00 region with modified data at offset 0x100. len is 32 bytes.

Re: LPC5528 Simple CRP enable/disable

bressan — Tue, 26 Apr 2022 09:04:14 GMT

I was able to write, if len==0x200.
It seems, like I must write the full page at once. So, why is there a parameter for the length?

Re: LPC5528 Simple CRP enable/disable

Alice_Yang — Wed, 27 Apr 2022 06:57:49 GMT

Hello Bressan,

Yes, the length must equal the page size.

There may be different length for other part flash page.

Alice

Re: LPC5528 Simple CRP enable/disable

bressan — Mon, 23 May 2022 14:24:36 GMT

For all users, which want to implement simple CRP (Code Read Protection) for LPC55xx / LPC55Sxx:

Disable debug, and fully read protection: CMPA cc_socu_pin / cc_socu_dflt to 0xFC0003FF / 0xFFFF0000

Reenable debug: CMPA cc_socu_pin / cc_socu_dflt to 0/0 and CFPA set all 0 and increase version.