N25Q128 Datasheet, PDF (32/185 Pages) Numonyx B.V – 128-Mbit, 1.8 V, multiple I/O, 4-Kbyte subsector erase on boot sectors, XiP enabled, serial flash memory with 108 MHz SPI bus interface

Volatile and Non Volatile Registers
6
Volatile and Non Volatile Registers
N25Q128 - 1.8 V
The device features many different registers to store, in volatile or non volatile mode, many
parameters and operating configurations:
„ Legacy SPI Status Register
„ 3 configuration registers:
– Non Volatile Configuration Register (NVCR), 16 bits
– Volatile Configuration Register (VCR), 8 bits
– Volatile Enhanced Configuration Register (VECR), 8 bits
The Non Volatile Configuration Register (NVCR) affects the memory configuration starting
from the successive power-on. It can be used to make the memory start in a determined
condition.
The VCR and VECR affect the memory configuration after every execution of the related
Write Volatile configuration Register (WRVCR) and Write Enhanced Volatile Configuration
register (WRVECR) instructions. These instructions overwrite the memory configuration set
at POR by NVCR.
As described in Figure 8.: Non Volatile and Volatile configuration Register Scheme, the
working condition of the memory is set by an internal configuration register, which is not
accessible by the user. The working parameters of the internal configuration register are
loaded from the NVCR during the boot phase of the device. In this sense the NVCR can be
seen as having the default settings of the memory.
During the normal life of the application, every time a write volatile or enhanced volatile
configuration register instruction is performed, the new configuration parameters set in the
volatile registers are also copied in the internal configuration register, thus instantly affecting
the memory behavior. Please note that on the next power on the memory will start again in
the working protocol set by the Non Volatile Register parameters.
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