CAT93C56/57
Erase
Upon receiving an ERASE command and address, the
CS (Chip Select) pin must be deasserted for a minimum
of t
CSMIN
. The falling edge of CS will start the self clocking
clear cycle of the selected memory location. The clocking
of the SK pin is not necessary after the device has
entered the self clocking mode. The ready/busy status of
the CAT93C56/57 can be determined by selecting the
device and polling the DO pin. Once cleared, the content
of a cleared location returns to a logical “1” state.
Erase/Write Enable and Disable
The CAT93C56/57 powers up in the write disable state.
Any writing after power-up or after an EWDS (write
disable) instruction must first be preceded by the EWEN
(write enable) instruction. Once the write instruction is
enabled, it will remain enabled until power to the device
is removed, or the EWDS instruction is sent. The EWDS
instruction can be used to disable all CAT93C56/57
write and clear instructions, and will prevent any
accidental writing or clearing of the device. Data can be
read normally from the device regardless of the write
enable/disable status.
Erase All
Upon receiving an ERAL command, the CS (Chip Select)
pin must be deselected for a minimum of t
CSMIN
. The
falling edge of CS will start the self clocking clear cycle
of all memory locations in the device. The clocking of the
SK pin is not necessary after the device has entered the
self clocking mode. The ready/busy status of the
CAT93C56/57 can be determined by selecting the device
and polling the DO pin. Once cleared, the contents of all
memory bits return to a logical “1” state.
Write All
Upon receiving a WRAL command and data, the CS
(Chip Select) pin must be deselected for a minimum of
t
CSMIN
. The falling edge of CS will start the self clocking
data write to all memory locations in the device. The
clocking of the SK pin is not necessary after the device
has entered the self clocking mode. The ready/busy
status of the CAT93C56/57 can be determined by
selecting the device and polling the DO pin. It is not
necessary for all memory locations to be cleared before
the WRAL command is executed.
Figure 4. Erase Instruction Timing
SK
CS
AN
DI
1
1
1
tSV
HIGH-Z
DO
AN-1
A0
STATUS VERIFY
tCS
STANDBY
tHZ
BUSY
tEW
READY
HIGH-Z
Doc. No. 1088, Rev. M
6
CATALYST [ CATALYST SEMICONDUCTOR ]
