Lpc2000

Was Philips misleading us about Code Read Protection?

The preliminary user manual for LPC2119/2129/2194/2292/2294 dated 2004
May 03 in the section on CRP states:

> When the code read protection is enabled the JTAG debug
> port, external memory boot and the following ISP commands
> are disabled:
>
> • Read Memory
> • Write to RAM
> • Go
> • Copy RAM to Flash
>
> The ISP commands mentioned above terminate with return
> code CODE_READ_PROTECTION_ENABLED.
>
> The ISP erase command only allows erasure of all user
> sectors when the code read protection is enabled.

Philips stated (by way of poster dated Sat Dec 17, 2005  11:52 AM)
that the purpose of CRP as:

> Code Read Protection (CRP) was implemented with intention
> to protect on-chip Flash content from preying eyes.

It appears that Philips made these claims while it knew that CRP can
be defeated by other methods, including parallel programming or
booting from external memory.

1/  LPC parts without external memory interface support parallel
programming.  This method can be used to read and write on-chip flash.

2/  On LPC parts with external memory, it is possible to force the
part to boot on external memory.  Code in external memory can read and
write on-chip flash.

If the above claims are not true, it would be a simple matter for
Philips to say so.  The fact that Philips has chosen to go quiet on
this issue seems to suggest the claims are indeed true.

If this is the case, then clearly Philips has intentionally misled us.

Comments anyone?

Jaya