MBM29LV800TE/BE60/70/90
If hardware reset occurs during the programming operation, it is impossible to guarantee the data are being
written.
Programming is allowed in any sequence and across sector boundaries. Beware that a data “0” cannot be
programmed back to a “1”. Attempting to do so may either hang up the device or result in an apparent success
according to the data polling algorithm but a read from read/reset mode will show that the data is still “0”. Only
erase operations can convert “0”s to “1”s.
“Embedded ProgramTM Algorithm” in “■ FLOW CHART” illustrates the Embedded ProgramTM Algorithm using
typical command strings and bus operations.
Chip Erase
Chip erase is a six bus cycle operation. There are two “unlock” write cycles. These are followed by writing the
“set-up” command. Two more “unlock” write cycles are then followed by the chip erase command.
Chip erase does not require the user to program the device prior to erase. Upon executing the Embedded Erase
Algorithm command sequence the devices will automatically program and verify the entire memory for an all
zero data pattern prior to electrical erase (Preprogram function) . The system is not required to provide any
controls or timings during these operations.
The automatic erase begins on the rising edge of the last WE pulse in the command sequence and terminates
when the data on DQ7 is “1” (See Write Operation Status section.) at which time the device returns to read the
mode.
Chip Erase Time; Sector Erase Time × All sectors + Chip Program Time (Preprogramming)
“Embedded EraseTM Algorithm” in “■ FLOW CHART” illustrates the Embedded EraseTM Algorithm using typical
command strings and bus operations.
Sector Erase
Sector erase is a six bus cycle operation. There are two “unlock” write cycles. These are followed by writing the
“set-up” command. Two more “unlock” write cycles are then followed by the Sector Erase command. The sector
address (any address location within the desired sector) is latched on the falling edge of WE, while the command
(Data = 30h) is latched on the rising edge of WE. After time-out of “tTOW” from the rising edge of the last sector
erase command, the sector erase operation will begin.
Multiple sectors may be erased concurrently by writing the six bus cycle operations on “MBM29LV800TE/BE
Command Definitions” in “■ DEVICE BUS OPERATION”. This sequence is followed with writes of the Sector
Erase command to addresses in other sectors desired to be concurrently erased. The time between writes must
be less than “tTOW” otherwise that command will not be accepted and erasure will not start. It is recommended
that processor interrupts be disabled during this time to guarantee this condition. The interrupts can be re-
enabled after the last Sector Erase command is written. A time-out of “tTOW” from the rising edge of the last WE
will initiate the execution of the Sector Erase command (s) . If another falling edge of the WE occurs within the
“tTOW” time-out window the timer is reset. (Monitor DQ3 to determine if the sector erase timer window is still open,
see section DQ3, Sector Erase Timer.) Once execution has begun resetting the devices will corrupt the data in
the sector. In that case, restart the erase on those sectors and allow them to complete. (Refer to the Write
Operation Status section for Sector Erase Timer operation.) Loading the sector erase buffer may be done in any
sequence and with any number of sectors (0 to 18) .
Sector erase does not require the user to program the devices prior to erase. The devices automatically program
all memory locations in the sector (s) to be erased prior to electrical erase (Preprogram function) . When erasing
a sector or sectors the remaining unselected sectors are not affected. The system is not required to provide any
controls or timings during these operations.
The automatic sector erase begins after the “tTOW” time out from the rising edge of the WE pulse for the last
sector erase command pulse and terminates when the data on DQ7 is “1” (See Write Operation Status section.)
at which time the devices return to the read mode. Data polling must be performed at an address within any of
the sectors being erased. Multiple Sector Erase Time; [Sector Erase Time + Sector Program Time (Preprogram-
ming) ] × Number of Sector Erase
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FUJITSU [ FUJITSU ]
