Numonyxâ„¢ Wireless Flash Memory (W30)

Numonyx Wireless Flash Memory (W30) (W30)
Locking operations cannot occur during program suspend. Appendix A, “Write State
Machine” on page 86 shows valid commands during erase suspend.
13.1.6 Status Register Error Checking
Using nested locking or program command sequences during erase suspend can
introduce ambiguity into status register results.
Because locking changes require 2-cycle command sequences—for example, 60h
followed by 01h to lock a block—following the Configuration Setup command (60h) with
an invalid command produces a command sequence error (SR[5:4]=11b).
If a Lock Block command error occurs during erase suspend, the flash device sets
SR[4] and SR[5] to 1 even after the erase resumes. When erase is complete, possible
errors during the erase cannot be detected from the status register, because of the
previous locking command error. A similar situation occurs if a program operation error
is nested within an erase suspend.
13.1.7 WP# Lock-Down Control
The Write Protect signal, WP#, adds an additional layer of block security. WP# affects
only blocks that previously had the Lock-Down command written to them.
• After the lock-down status bit is set for a block, asserting WP# forces that block
into the lock-down state [011] and prevents it from being unlocked.
• After WP# is deasserted, the state of the block reverts to locked [111]. Software
commands can then unlock the block (for erase or program operations) and
subsequently re-lock it.
Only flash device reset or power-down can clear the lock-down status bit and render
WP# ineffective.
Datasheet November 2007
74 Order Number: 290702-13