W19B320ATB Datasheet, PDF (9/53 Pages) Winbond – 4M × 8/2M × 16 BITS 3V FLEXIBLE BANK FLASH MEMORY

W19B320AT/B
6.1.7 #RESET: Hardware Reset Pin
The #RESET pin provides a hardware method to reset the device to reading array data. When the
#RESET pin is set to low for at least a period of t_RP, the device will immediately terminate every
operation in progress, tri-states all output pins, and ignores all read/write commands for the duration
of the #RESET pulse. The device also resets the internal state machine to reading array data mode.
To ensure data integrity, the interrupted operation needs to be reinitiated when the device is ready to
accept another command sequence.
Current is reduced for the duration of the #RESET pulse. When #RESET is held at V_SS ± 0.3V, the
device initiates the CMOS standby current (I_CC4). If #RESET is held at V_IL but not within V_SS ± 0.3V,
the standby current will be greater.
The #RESET pin may be tied to the system-reset circuitry. Thus the system reset would also reset the
device, enabling the system to read the boot-up firmware from the device.
If #RESET is asserted during the program or erase operation, the RY/#BY pin will be at “0” (busy) until
the internal reset operation is complete. If #RESET is asserted when a program or erase operation is
not processing (RY/#BY pin is “1”), the reset operation is completed within a time of t_READY (not during
Embedded Algorithms). After the #RESET pin returns to V_IH, the system can read data t_RH.
6.1.8 Output Disable Mode
When the #OE input is at V_IH, output from the device is disabled. The output pins are set in the high
impedance state.
6.1.9 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 V_ID (8.5V to 12.5V) 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.
6.1.10 Sector/Sector Block Protection and Unprotection
The hardware sector protection feature disables both program and erasure operations in any sectors.
The hardware sector Unprotection feature re-enables both program and erasure operations in
previously protected sectors. Sector Protection/Unprotection can be implemented through two
methods.
The primary method requires V_ID 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 V_ID on address pin A9 and #OE. It
is possible to determine whether a sector is protected or unprotected. See the Application Note for detail
information.
Publication Release Date: December 27, 2005
-9-
Revision A4