at49sn6416 ATMEL Corporation, at49sn6416 Datasheet - Page 7

• Manufacturer Part Number: at49sn6416
• Description: 64-megabit 4m X 16 Burst/page Mode 1.8-volt Flash Memory
• Manufacturer: ATMEL Corporation

3.11
3.12
3.12.1
3.12.2
3464C–FLASH–2/05
Word Programming
Flexible Sector Protection
Softlock and Unlock
Hardlock and Write Protect (WP)
The device is programmed on a word-by-word basis. Programming is accomplished via the
internal device command register and is a two-bus cycle operation. The programming address
and data are latched in the second cycle. The device will automatically generate the required
internal programming pulses. Please note that a “0” cannot be programmed back to a “1”; only
erase operations can convert “0”s to “1”s.
The AT49SN6416(T) offers two sector protection modes, the Softlock and the Hardlock. The
Softlock mode is optimized as sector protection for sectors whose content changes frequently.
The Hardlock protection mode is recommended for sectors whose content changes infrequently.
Once either of these two modes is enabled, the contents of the selected sector is read-only and
cannot be erased or programmed. Each sector can be independently programmed for either the
Softlock or Hardlock sector protection mode. At power-up and reset, all sectors have their Soft-
lock protection mode enabled.
The Softlock protection mode can be disabled by issuing a two-bus cycle Unlock command to
the selected sector. Once a sector is unlocked, its contents can be erased or programmed. To
enable the Softlock protection mode, a two-bus cycle Softlock command must be issued to the
selected sector.
The Hardlock sector protection mode operates in conjunction with the Write Protection (WP) pin.
The Hardlock sector protection mode can be enabled by issuing a two-bus cycle Hardlock soft-
ware command to the selected sector. The state of the Write Protect pin affects whether the
Hardlock protection mode can be overridden.
To disable the Hardlock sector protection mode, the chip must be either reset or power cycled.
• When the WP pin is low and the Hardlock protection mode is enabled, the sector cannot be
• When the WP pin is high, the Hardlock protection mode is overridden and the sector can be
unlocked and the contents of the sector is read-only.
unlocked via the Unlock command.
AT49SN6416(T)
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