W19B(L)320ST/B
6.1.7 Output Disable Mode
When the #OE input is at VIH, output from the device is disabled. The output pins are set in the high
impedance state.
6.1.8 Autoselect Mode
The autoselect mode offers manufacturer and device identification, as well as sector protection
verification, through identifier codes output on DQ0−DQ7. This mode is primarily intended for
programming equipment to automatically match a device to be programmed with its corresponding
programming algorithm. However, the autoselect codes can also be accessed in-system through the
command register.
When using programming equipment, the autoselect mode requires VID (8.5 V to 12.5 V) on address
pins A9. Address pins A6, A1, and A0 must be as shown in table. In addition, when verifying sector
protection, the sector address must appear on the appropriate highest order address bits. When all
necessary bits have been set as required, the programming equipment may then read the
corresponding identifier code on DQ0−DQ7.
To access the autoselect codes in-system, the host system can issue the autoselect command
through the command register. This method does not require VID. Also refer to the Autoselect
Command Sequence section for more information.
6.1.9 Sector/Sector Block Protection and Unprotection
The hardware sector protection feature disables both program and erase operations in any sectors.
The hardware sector unprotection feature re-enables both program and erase operations in previously
protected sectors. Sector protection/unprotection can be implemented through two methods.
The primary method requires VID on the #RESET pin, and can be implemented either in-system or through
programming equipment. This method uses standard microprocessor bus cycle timing.
The alternate method intended only for programming equipment requires VID on address pin A9 and #OE It
is possible to determine whether a sector is protected or unprotected. See the Autoselect Mode section for
details.
6.1.10 Write Protect (
#WP
)
The Write Protect function provides a hardware method to protect the certain boot sectors without
using VID. This function is one of two features provided by the #WP/ACC pin.
When the #WP/ACC pin is set at VIL, the device disables program and erase functions in the two
outermost 8 Kbyte boot sectors independently of whether those sectors were protected or unprotected
using the method described in “Sector/Sector Block Protection and Unprotection.” The two outermost
8 Kbyte boot sectors are the two sectors containing either the lowest addresses in a bottom-boot-
configured device or the highest addresses in a top-boot-configured device.
When the #WP/ACC pin is set at VIH, the device reverts to the two outermost 8K Byte boot sectors
were last set either to be protected or unprotected. That is, sector protection or unprotection for these
two sectors depends on whether they were last protected or unprotected using the method described
in “Sector/Sector Block Protection and Unprotection”.
Please note that the #WP/ACC pin must not be left floating or unconnected; otherwise, the
inconsistent behavior of the device may occur.
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