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W39V040A Datasheet(PDF) 4 Page - Winbond

No. de Pieza. W39V040A
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Fabricante  WINBOND [Winbond]
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W39V040A Datasheet(HTML) 4 Page - Winbond

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block, it will not partially lock the 16Kbytes boot block. You can check the DQ2/DQ3 at the address
7FFF2 to see whether the #TBL/#WP pin is in low or high state. If the DQ2 is "0", it means the #TBL pin
is tied to high state. In such condition, whether boot block can be programmed/erased or not will depend
on software setting. On the other hand, if the DQ2 is "1", it means the #TBL pin is tied to low state, then
boot block is locked no matter how the software is set. Like the DQ2, the DQ3 inversely mirrors the #WP
state. If the DQ3 is "0", it means the #WP pin is in high state, then all the sectors except the boot block
can be programmed/erased. On the other hand, if the DQ3 is "1", then all the sectors except the boot
block are programmed/erased inhibited.
To return to normal operation, perform a three-byte command sequence (or an alternate single-byte
command) to exit the identification mode. For the specific code, see Command Codes for
Identification/Boot Block Lockout Detection.
Chip Erase Operation
The chip-erase mode can be initiated by a six-byte command sequence. After the command loading
cycle, the device enters the internal chip erase mode, which is automatically timed and will be completed
within fast 100 mS (max). The host system is not required to provide any control or timing during this
operation. If the boot block programming lockout is activated, only the data in the other memory sectors
will be erased to FF(hex) while the data in the boot block will not be erased (remains as the same state
before the chip erase operation). The entire memory array will be erased to FF(hex) by the chip erase
operation if the “boot block programming lockout feature” is not activated. The device will automatically
return to normal read mode after the erase operation completed. Data polling and/or Toggle Bits can be
used to detect end of erase cycle.
Sector/Page Erase Operation
Sector/page erase is a six-bus cycles operation. There are two "unlock" write cycles, followed by writing
the "set-up" command. Two more "unlock" write cycles then follows by the sector/page erase command.
The sector/page address (any address location within the desired sector/page) is latched on the rising
edge of R/C, while the command (30H/50H) is latched on the rising edge of #WE in programmer mode.
Sector/page erase does not require the user to program the device prior to erase. When erasing a
sector/page or sectors/pages the remaining unselected sectors/pages are not affected. The system is
not required to provide any controls or timings during these operations.
The automatic sector/page erase begins after the erase command is completed, right from the rising
edge of the #WE pulse for the last sector/page erase command pulse and terminates when the data on
DQ7, Data Polling, is "1" at which time the device returns to the read mode. Data Polling must be
performed at an address within any of the sectors/pages being erased.
Refer to the Erase Command flow Chart using typical command strings and bus operations.
Program Operation
The W39V040A is programmed on a byte-by-byte basis. Program operation can only change logical
data "1" to logical data "0." The erase operation, which changed entire data in main memory and/or boot
block from "0" to "1", is needed before programming.
The program operation is initiated by a 4-byte command cycle (see Command Codes for Byte
Programming). The device will internally enter the program operation immediately after the
byte-program command is entered. The internal program timer will automatically time-out (50
µS max. -
TBP) once it is completed and then return to normal read mode. Data polling and/or Toggle Bits can be
used to detect end of program cycle.

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