Overview - Fujitsu 8FX Hardware Manual

CHAPTER 27 NON-VOLATILE REGISTER (NVR) INTERFACE

27.1 Overview

27.1 Overview
The NVR (Non-Volatile Register) area is a reserved area in the Flash that stores
system information and option settings. After a reset, data in the NVR Flash
area will be fetched and stored in registers in the NVR I/O area. In the
MB95630H Series, the NVR interface is used to store the following data:
• Coarse trimming value for main CR Clock (5 bits)
• Fine trimming value for main CR Clock (5 bits)
• Watchdog timer selection ID (16 bits)
• Temperature dependent adjustment value for main CR clock (5 bits)
■ Functions of NVR Interface
Functions of the NVR interface are as follows:
1. The NVR interface retrieves all data from the NVR Flash area and stores it in the registers
in the NVR I/O area after a reset. See Figure 27.1-1 and Figure 27.2-1.
2. The NVR interface enables the user to know the value of the initial CR trimming setting.
3. The NVR interface enables the user to select the hardware watchdog timer or software
watchdog timer by modifying the 16-bit watchdog timer selection ID. The watchdog timer
selection ID cannot be modified while the CPU is running.
Figure 27.1-1 shows the retrieval of NVR during a reset.
NVR Interface
(I/O Area)
NVR
(Flash Area)
582
Figure 27.1-1 Retrieval of NVR during Reset
0x0FE4
0x0FE5
0x0FE7
0x0FEB
0x0FEC
0xFFBB
0xFFBC
0xFFBD
0xFFBE
0xFFBF
Memory Map
FUJITSU SEMICONDUCTOR LIMITED
MB95630H Series
0bXXX01010
0bXXX00001
0bXXX10101
0b11111111
0b00000000
0bXXX10101
0bXXX01010
0bXXX00001
0b11111111
0b00000000
MN702-00009-2v0-E