M36DR432AD Datasheet, PDF (15/52 Pages) STMicroelectronics – 32 Mbit 2Mb x16, Dual Bank, Page Flash Memory and 4 Mbit 256Kb x16 SRAM, Multiple Memory Product

M36DR432AD, M36DR432BD
The command uses the two unlock cycles followed
by a write cycle to setup the command. A further
four cycles are required to latch the address and
data of the four Words and start the Program
Erase Controller.
The Quadruple Word Program command can be
executed in Bypass mode to skip the two unlock
cycles.
Note that the Quadruple Word Program command
cannot change a bit set to ’0’ back to ’1’. One of the
Erase Commands must be used to set all the bits
in a block or in the whole bank from ’0’ to ’1’. If the
Quadruple Word Program command is used to try
to set a bit from ‘0’ to ‘1’ Status Register Error bit
DQ5 will be set to ‘1’.
Enter Bypass Mode Command. The Bypass
mode is used to reduce the overall programming
time when large memory arrays need to be pro-
grammed.
The Enter Bypass Mode command uses the two
unlock cycles followed by one write cycle to set up
the command. Once in Bypass mode, it is impera-
tive that only the following commands be issued:
Exit Bypass, Program, Double Word Program or
Quadruple Word Program.
Exit Bypass Mode Command. The Exit Bypass
Mode command uses two write cycles to setup
and confirm the command. The unlock cycles are
not required. After the Exit Bypass Mode com-
mand, the device resets to Read mode.
Program in Bypass Mode Command. The
Program in Bypass Mode command can be is-
sued when the device is in Bypass mode (issue a
Enter Bypass Mode command). It uses the same
sequence of cycles as the Program command with
the exception of the unlock cycles.
Double Word Program in Bypass Mode Com-
mand. The Double Word Program in Bypass
Mode command can be issued when the device is
in Bypass mode (issue a Enter Bypass Mode com-
mand). It uses the same sequence of cycles as the
Double Word Program command with the excep-
tion of the unlock cycles.
Quadruple Word Program in Bypass Mode
Command. The Quadruple Word Program in By-
pass Mode command can be issued when the de-
vice is in Bypass mode (issue a Enter Bypass
Mode command). It uses the same sequence of
cycles as the Quadruple Word Program command
with the exception of the unlock cycles.
Block Lock Command. The Block Lock com-
mand is used to lock a block and prevent Program
or Erase operations from changing the data in it.
All blocks are locked at power-up or reset.
Three Bus Write cycles are required to issue the
Block Lock command.
s The first two bus cycles unlock the Command
Interface.
s The third bus cycle sets up the Block Lock
command and latches the block address.
The lock status can be monitored for each block
using the Auto Select command. Table 10 shows
the Lock Status after issuing a Block Lock com-
mand.
The Block Lock bits are volatile, once set they re-
main set until a hardware reset or power-down/
power-up. They are cleared by a Blocks Unlock
command. Refer to the section, Block Locking, for
a detailed explanation.
Block Unlock Command. The Blocks Unlock
command is used to unlock a block, allowing the
block to be programmed or erased.
Three Bus Write cycles are required to issue the
Blocks Unlock command.
s The first two bus cycles unlock the Command
Interface.
s The third bus cycle sets up the Block UnLock
command and latches the block address.
The lock status can be monitored for each block
using the Auto Select command. Table 10 shows
the lock status after issuing a Block Unlock com-
mand. Refer to the section, Block Locking, for a
detailed explanation.
Block Lock-Down Command. A locked or un-
locked block can be locked-down by issuing the
Block Lock-Down command. A locked-down block
cannot be programmed or erased, or have its pro-
tection status changed when WPF is Low, V_IL.
When WPF is High, V_IH, the Lock-Down function is
disabled and the locked blocks can be individually
unlocked by the Block Unlock command.
Three Bus Write cycles are required to issue the
Block Lock-Down command.
s The first two bus cycles unlock the Command
Interface.
s The third bus cycle sets up the Block Lock-
Down command and latches the block address.
The lock status can be monitored for each block
using the Auto Select command. Locked-Down
blocks revert to the locked (and not locked-down)
state when the device is reset on power-down. Ta-
ble 10 shows the Lock Status after issuing a Block
Lock-Down command. Refer to the section, Block
Locking, for a detailed explanation.
Block Erase Command. The Block Erase com-
mand can be used to erase a block. It sets all the
bits within the selected block to ’1’. All previous
data in the block is lost. If the block is protected
then the Erase operation will abort, the data in the
block will not be changed and the device will return
to Read Array mode. It is not necessary to pre-pro-
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