PN7642 code read protect

[artem_pn]

Hello! 

I am using PN7642 in my project. I would like to ask, how to protect code from reading properly?

In the datasheet I found description of CRP Levels (CRP1, CRP2, CRP3).  In library the is function PN76_Status_t PN76_Sys_OTPConfigs_EnableCRP(). I would like to ask how to use it properly? Where in code it should be called? What level of code read protection it provides? How to check if it works? 

I called it from main() function, it returned 0x07 value (what can cause that? it seems like possible values are 0x00 and 0x08) and I still can read memory using JLink utility. 

Thank you in advance!

Artem 

[jimmychan · Accepted solution]

Please open the API User documentation.

Then go to the OTP (One Time Programable) calls:

You could find all kind of security features to protect the chip such as Read protection, SWD disable and so on.

[KB1]

I also am getting a 0x07 return code.  The API documentation you pointed to has no useful information about what code 7 "PN76_STATUS_AUTH_ERROR" means or how to deal with it.

Can you please provide more information on how to utilize the Code Read Protection functionality in the chip?

[artem_pn]

Hello!

The function PN76_Sys_OTPConfigs_EnableCRP() can be called only once. After that trying to debug it, I have got this 0x07 message, but it turned off an ability for me to run device in USB FW update mode by selecting boot from USB on evaluation board