TFE-4/RV-1
Company Confidential
TF4 Technical Information
Nokia Customer Care
Page 8b-28
Copyright
©
2005
Nokia Corporation.
Issue 2.0 Mar/2005
Company Confidential
Lock-down block.
Locked-down blocks are protected from program and erase operations (just like locked
blocks), but software commands alone cannot change their protection status. A locked-
down block can only be unlocked when the WP-signal is high. When the WP-signal goes
low, all locked-down blocks revert to locked. A locked or unlocked block can be locked-
down by writing a "Lock-Down Block command" sequence. Locked-down blocks revert to
the locked state at device reset or power-down.
AMD:
All blocks have a locking latch and upon power up all blocks are locked. To unlock
a block a command sequence must be written, once the command unlock sequence is
written the SW can unlock as many blocks as required by entering the block address
while keeping a specific address high. If the address is taken to low, the block will be
locked instead of unlocked. The SW locking is similar to the Intel SW locking.
The AMD flash does also have the same hardware lock as Intel. The signal or pin is called
WP (write protect). The blocks are locked if WP is set to low. If the WP-signal is set high
then the SW can control the locking of the blocks. Finally, if the VPP pin is set to low all
blocks are locked.
Read While Write (RWW).
The device is capable of reading data from one Bank of the memory while programming
or erasing in the other Bank of the memory. An erase operation may also be suspend to
read from or program to another location within the same Bank (except the sector being
erased).
Burst mode.
The flash device supports burst-mode. The purpose is to improve the date rate between
the flash and the UPP. The burst-mode can only be used for read operations. It is possible
to access the memory in burst-mode over the entire memory except for the 8 x 8 Kbytes
sectors. When using burst-mode at least 4 word (4*16bits) is read from the flash. A read
operation from the flash, normally first set-up the address, and then the UPP will get the
data from this particular address. The address has to be set-up or sent to the flash ever
time the UPP wants to read from the flash. By using burst-mode the address only needs
to be sent one time, then flash will keep sending data as long as there is a clock-signal.
Figure 14: Description of Burst-Mode access