SAM7X256_14 Datasheet, PDF (203/662 Pages) ATMEL Corporation – ARM-based Flash MCU

 NVPTYP and NVPSIZ - identifies the type of embedded non-volatile memory and its size
 ARCH - identifies the set of embedded peripheral
 SRAMSIZ - indicates the size of the embedded SRAM
 EPROC - indicates the embedded ARM processor
 VERSION - gives the revision of the silicon
The second register is device-dependent and reads 0 if the bit EXT is 0.
26.4.8 ICE Access Prevention
The Debug Unit allows blockage of access to the system through the ARM processor's ICE interface. This feature is
implemented via the register Force NTRST (DBGU_FNR), that allows assertion of the NTRST signal of the ICE Interface.
Writing the bit FNTRST (Force NTRST) to 1 in this register prevents any activity on the TAP controller.
On standard devices, the FNTRST bit resets to 0 and thus does not prevent ICE access.
This feature is especially useful on custom ROM devices for customers who do not want their on-chip code to be visible.
SAM7X Series [DATASHEET]
6120K–ATARM–11-Feb-14
203