S71PL129JC0 datasheet(39/153 Pages) SPANSION

39 / 153 page

October 28, 2005 S71PL129Jxx_00_A8

S71PL129JC0/S71PL129JB0/S71PL129JA0

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Informatio n

Persistent Protection Bit Lock

The Persistent Protection Bit (PPB) Lock is a volatile bit that reflects the state of

the Password Mode Locking Bit after power-up reset. If the Password Mode Lock

Bit is also set after a hardware reset (RESET# asserted) or a power-up reset, the

ONLY means for clearing the PPB Lock Bit in Password Protection Mode is to issue

the Password Unlock command. Successful execution of the Password Unlock

command clears the PPB Lock Bit, allowing for sector PPBs modifications. Assert-

ing RESET#, taking the device through a power-on reset, or issuing the PPB Lock

Bit Set command sets the PPB Lock Bit to a “1” when the Password Mode Lock Bit

is not set.

If the Password Mode Locking Bit is not set, including Persistent Protection Mode,

the PPB Lock Bit is cleared after power-up or hardware reset. The PPB Lock Bit is

set by issuing the PPB Lock Bit Set command. Once set the only means for clear-

ing the PPB Lock Bit is by issuing a hardware or power-up reset. The Password

Unlock command is ignored in Persistent Protection Mode.

High Voltage Sector Protection

Sector protection and unprotection may also be implemented using programming

equipment. The procedure requires high voltage (VID) to be placed on the RE-

SET# pin. Refer to Figure 1 for details on this procedure. Note that for sector

unprotect, all unprotected sectors must first be protected prior to the first sector

write cycle.

S71PL129JC0 Datasheet(PDF) 39 Page - SPANSION