MBM29F160TE Ver la hoja de datos (PDF) - Fujitsu
Número de pieza
componentes Descripción
Fabricante
MBM29F160TE Datasheet PDF : 53 Pages
| |||
MBM29F160TE-55/-70/-90/MBM29F160BE-55/-70/-90
Write
Device erasure and programming are accomplished via the command register. The command register serve as
inputs to the internal state machine. The state machine outputs dictate the function of the device.
The command register itself does not occupy any addressable memory location. The register is latch used to
store the commands, along with the address and data information needed to execute the command. The
command register is written by bringing WE to VIL, while CE is at VIL and OE is at VIH. Addresses are latched on
the falling edge of CE or WE, whichever occurs later, while data is latched on the rising edge of CE or WE pulse,
whichever occurs first. Standard microprocessor write timings are used.
Refer to AC Write Characteristics and the Erase/Programming Waveforms for specific timing parameters.
Write Protect (WP)
The write Protect function provides a hardware method of protecting certain boot sectors without using VID.
If the system asserts VIL on the WP pin, the device disables program and erase functions in the "outermost" 16K
byte boot sectors independently of whether this sector was protected or unprotected using the method described
in "Sector / Sector Block Protection and Unprotection". The outmost 16K byte boot sector is the sector containing
the lowest addresses in a bottom-boot-configured devices, or the sector containing the highest addresses in a
top-boot-configured device.
If the system asserts VIH on the WP pin, the devices reverts to whether the outmost 16K byte boot sector was
last set to be protected or unprotected. That is, sector protection or unprotection for this sector depends on
whether it was last protected or unprotected using the method describe in "Sector / Sector Block Protection and
Unprotection".
Sector Protection
The MBM29F160TE/BE features hardware sector protection. This feature will disable both program and erase
operations in any number of sectors (0 through 34). The sector protection feature is enabled using programming
equipment at the user’s site. The device is shipped with all sectors unprotected.
To activate this mode, the programming equipment must force VID on address pin A9 and control pin OE, (suggest
VID = 11.5V), CE = VIL, and A6 = VIL. The sector addresses (A19, A18, A17, A16, A15, A14, A13, and A12) should be set
to the sector to be protected. Tables 5 and 6 define the sector address for each of the thirty five (35) individual
sectors. Programming of the protection circuitry begins on the falling edge of the WE pulse and is terminated
with the rising edge of the same. Sector addresses must be held constant during the WE pulse. See figures 16
and 24 for sector protection waveforms and algorithm.
To verify programming of the protection circuitry, the programming equipment must force VID on address pin A9
with CE and OE at VIL and WE at VIH. Scanning the sector addresses (A19, A18, A17, A16, A15, A14, A13, and A12)
while (A6, A1, A0) = (0, 1, 0) will produce a logical “1” code at device output DQ0 for a protected sector. Otherwise
the devices will read 00H for unprotected sector. In this mode, the lower order addresses, except for A0, A1, and
A6 are DON’T CARES. Address locations with A1 = VIL are reserved for Autoselect manufacturer and device
codes. A-1 requires to apply to VIL in byte mode.
It is also possible to determine if a sector is protected in the system by writing an Autoselect command. Performing
a read operation at the address location XX02H, where the higher order addresses pins (A19, A18, A17, A16, A15,
A14, A13, and A12) represents the sector address will produce a logical “1” at DQ0 for a protected sector. See
Tables 4.1 and 4.2 for Autoselect codes.
Temporary Sector Unprotection
This feature allows temporary unprotection of previously protected sectors of the MBM29F160TE/BE devices
in order to change data. The Sector Unprotection mode is activated by setting the RESET pin to high voltage
(12 V). During this mode, formerly protected sectors can be programmed or erased by selecting the sector
addresses. Once the 12 V is taken away from the RESET pin, all the previously protected sectors will be protected
again. Refer to Figures 18 and 25.
14
Share Link: 