s71gl128nc0 Meet Spansion Inc., s71gl128nc0 Datasheet - Page 79

• Manufacturer Part Number: s71gl128nc0
• Description: Stacked Multi-chip Product Mcp 512/256/128 Megabit 32/16/8 M X 16-bit Cmos 3.0 Volt-only Mirrorbittm Page-mode Flash Memory With 64 Megabit 4m X 16-bit Psram
• Manufacturer: Meet Spansion Inc.

December 15, 2004 S29GLxxxN_MCP_A1
Volatile Sector Protection Command Set
Reads and writes from the main memory are not allowed.
The PPB Lock Bit Set command is used to set the PPB Lock Bit to the “freeze state”
if it is cleared either at reset or if the Password Unlock command was successfully
executed. There is no PPB Lock Bit Clear command. Once the PPB Lock Bit is set
to the “freeze state”, it cannot be cleared unless the device is taken through a
power-on clear (for Persistent Protection Mode) or the Password Unlock command
is executed (for Password Protection Mode). If the Password Protection Mode Lock
Bit is programmed, the PPB Lock Bit status is reflected as set to the “freeze state”,
even after a power-on reset cycle.
The programming state of the PPB Lock Bit can be verified by executing a PPB
Lock Bit Status Read command to the device.
The Global Volatile Sector Protection Freeze Command Set Exit command
must be issued after the execution of the commands listed previously to reset the
device to read mode.
The Volatile Sector Protection Command Set permits the user to set the Dynamic
Protection Bit (DYB) to the “protected state”, clear the Dynamic Protection Bit
(DYB) to the “unprotected state”, and read the logic state of the Dynamic Protec-
tion Bit (DYB).
The Volatile Sector Protection Command Set Entry command sequence
must be issued prior to any of the commands listed following to enable proper
command execution.
Note that issuing the Volatile Sector Protection Command Set Entry com-
mand disables reads and writes from main memory.
The DYB Set and DYB Clear commands are used to protect or unprotect a DYB for
a given sector. The high order address bits are issued at the same time as the
code 00h or 01h on DQ7-DQ0. All other DQ data bus pins are ignored during the
data write cycle. The DYB bits are modifiable at any time, regardless of the state
of the PPB bit or PPB Lock Bit. The DYB bits are cleared to the “unprotected state”
at power-up or hardware reset.
—DYB Status Read Command
The programming state of the DYB bit for a given sector can be verified by writing
a DYB Status Read command to the device. This requires an initial access delay.
The Volatile Sector Protection Command Set Exit command must be issued
after the execution of the commands listed previously to reset the device to read
mode.
Note that issuing the Volatile Sector Protection Command Set Exit com-
mand re-enables reads and writes to the main memory.
PPB Lock Bit Set Command
PPB Lock Bit Status Read Command
DYB Set Command
DYB Clear Command
A d v a n c e
S29GLxxxN MirrorBit
I n f o r m a t i o n
TM
Flash Family
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