at49lw040 ATMEL Corporation, at49lw040 Datasheet - Page 11

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

Register-based
Locking and General-
purpose Input
Registers
3342A–FLASH–6/03
The new lock status will take place after the program or erase operation completes.
These pins function in combination with the register-based sector locking (to be
explained later). These pins, when active, will write-protect the appropriate sector(s),
regardless of the associated sector locking registers. (For example, when TBL is active,
writing to the top sector is prevented, regardless of the state of the Write Lock bit for the
top sector’s locking register. In such a case, clearing the write-protect bit in the register
will have no functional effect, even though the register may indicate that the sector is no
longer locked. The register may still be set to read-lock the sector, if desired.)
Device Memory Map with FWH Hardware Lock
Architecture
A series of registers are available in the FWH to provide software read and write locking
and GPI feedback. These registers are accessible through standard addressable mem-
ory space.
REGISTERS: The AT49LW040 has two types of registers: sector-locking registers and
general-purpose input registers. The two types of registers appear at their respective
address locations in the 4 GB system memory map.
SECTOR-LOCKING REGISTERS: The AT49LW040 has 8 (LR0 - LR7) sector-locking
registers. Each sector-locking register controls the lock protection for 64K bytes of mem-
ory as shown in Table 7. The sector-locking registers are accessible through the register
memory address shown in the third column of Table 7. The sector-locking registers are
read/write as shown in the last column of Table 7. Each sector has three dedicated lock-
ing bits as shown in Table 8 and Table 9.
Sector
SA0
SA1
SA2
SA3
SA4
SA5
SA6
SA7
Size (Bytes)
64K
64K
64K
64K
64K
64K
64K
64K
Address Range
00000 - 0FFFF
10000 - 1FFFF
20000 - 2FFFF
30000 - 3FFFF
40000 - 4FFFF
50000 - 5FFFF
60000 - 6FFFF
70000 - 7FFFF
Hardware Write-protect
AT49LW040
TBL
WP
WP
WP
WP
WP
WP
WP
Pin
11