CAT93C86
Erase All
Erase
UponreceivinganERALcommand,theCS(ChipSelect)
pin must be deselected for a minimum of tCSMIN. 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
CAT93C86 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.
Upon receiving an ERASE command and address, the
CS (Chip Select) pin must be deasserted for a minimum
oftCSMIN.ThefallingedgeofCSwillstarttheselfclocking
clearcycleoftheselectedmemorylocation.Theclocking
of the SK pin is not necessary after the device has
enteredtheselfclockingmode.Theready/busystatusof
the CAT93C86 can be determined by selecting the
deviceandpollingtheDOpin. Oncecleared, thecontent
of a cleared location returns to a logical “1” state.
Write All
Erase/Write Enable and Disable
Upon receiving a WRAL command and data, the CS
(Chip Select) pin must be deselected for a minimum of
tCSMIN. 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 CAT93C86 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.
TheCAT93C86powersupinthewritedisablestate. Any
writing after power-up or after an EWDS (write disable)
instruction must first be preceded by the EWEN (write
enable)instruction.Oncethewriteinstructionisenabled,
itwillremainenableduntilpowertothedeviceisremoved,
or the EWDS instruction is sent. The EWDS instruction
can be used to disable all CAT93C86 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.
Figure 4. Erase Instruction Timing
SK
STANDBY
STATUS VERIFY
CS
t
CS
A
A
0
A
N
N-1
DI
1
1
1
t
t
SV
HZ
HIGH-Z
DO
BUSY
EW
READY
HIGH-Z
t
Doc. No. 1091, Rev. M
6
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