S29PL-J55BAI011 datasheet(50/96 Pages) SPANSION

50 / 96 page

S29PL-J

S29PL-J_00_A9 September 22, 2006

Data

Sheet

(Adv an ce

Inf o r m a t io n)

13.3

Write Protect (WP#)

The Write Protect feature provides a hardware method of protecting the upper two and lower two sectors

without using VID. This function is provided by the WP# pin and overrides the previously discussed High

Voltage Sector Protection on page 48 method.

If the system asserts VIL on the WP#/ACC pin, the device disables program and erase functions in the two

outermost 4 Kword sectors on both ends of the flash array independent of whether it was previously protected

or unprotected.

If the system asserts VIH on the WP#/ACC pin, the device reverts the upper two and lower two sectors to

whether they were last set to be protected or unprotected. That is, sector protection or unprotection for these

sectors depends on whether they were last protected or unprotected using the method described in the High

Voltage Sector Protection on page 48.

Note that the WP#/ACC pin must not be left floating or unconnected; inconsistent behavior of the device may

result.

13.3.1

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

Unlock command is ignored in Persistent Protection Mode.

13.4

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 RESET# pin. Refer to Figure 13.1 on page 49 for details on

this procedure. Note that for sector unprotect, all unprotected sectors must first be protected prior to the first

sector write cycle.

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