at49lw040 ATMEL Corporation, at49lw040 Datasheet - Page 12

• Manufacturer Part Number: at49lw040
• Description: At49lw040 4-megabit Firmware Hub Flash Memory
• Manufacturer: ATMEL Corporation

Table 7. Sector-locking Registers for AT49LW040
Table 8. Function of Sector-locking Bits
Table 9. Register-based Locking Value Definitions
Note:
12
Register Name
LR0
LR1
LR2
LR3
LR4
LR5
LR6
LR7
FGPI-REG
Bit
7:3
2
1
0
Data
00
01
02
03
04
05
06
07
1. The Write Lock bit must be set to the desired protection state prior to starting a program or erase operation since it is sam-
AT49LW040
pled at the beginning of the operation. Changing the state of the Write Lock bit during a program or erase operation may
cause unpredictable results. The new lock status will take place after the program or erase operation completes. The individ-
ual bit functions are described in the following sections.
Reserved
Data 7 - 3
Function
Reserved
Read Lock
1 = Prevents read operations in the sector where set.
0 = Normal operation for reads in the sector where clear. This is the default state.
Lock-down
1 = Prevents further set or clear operations to the Write Lock and Read Lock bits. Lock-down can only be set, but not cleared. The
sector will remain locked-down until reset (with RST or INIT), or until the device is power-cycled.
0 = Normal operation for Write Lock and Read Lock bits altering in the sector where clear. This is the default state.
Write Lock
1 = Prevents program or erase operations in the sector where set. This is the default state.
0 = Normal operation for programming and erase in the sector where clear.
00000
00000
00000
00000
00000
00000
00000
00000
Sector Size
64K
64K
64K
64K
64K
64K
64K
64K
Read Lock,
Data 2
0
0
0
0
1
1
1
1
Lock-down,
Data 1
Register Memory Address
0
0
1
1
0
0
1
1
FFBC0002H
FFBD0002H
FFBC0100H
FFB80002H
FFB90002H
FFBA0002H
FFBB0002H
FFBE0002H
FFBF0002H
Write Lock,
Data 0
0
1
0
1
0
1
0
1
Resulting Sector State
Full access
Write locked. Default state at power-up
Locked open (full access locked down)
Write locked down
Read locked
Read and write locked
Read locked down
Read and write locked down
Default Value
01H
01H
01H
01H
01H
01H
01H
01H
N/A
(1)
3342A–FLASH–6/03
Type
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
RO