93LC66A-IP Microchip Technology, 93LC66A-IP Datasheet - Page 6

• Manufacturer Part Number: 93LC66A-IP
• Description: 4K 2.5V Microwire Serial EEPROM
• Manufacturer: Microchip Technology

93LC66A/B
3.6
The 93LC66A/B powers up in the ERASE/WRITE Dis-
able (EWDS) state. All programming modes must be
preceded by an ERASE/WRITE Enable (EWEN)
instruction. Once the EWEN instruction is executed,
programming remains enabled until an EWDS instruc-
tion is executed or Vcc is removed from the device. To
protect against accidental data disturbance, the EWDS
instruction can be used to disable all ERASE/WRITE
functions and should follow all programming opera-
tions. Execution of a READ instruction is independent
of both the EWDS and EWEN instructions.
FIGURE 3-4:
FIGURE 3-5:
FIGURE 3-6:
DS21209C-page 6
CLK
CLK
DO
CS
CS
DI
CLK
DI
CS
DI
ERASE/WRITE Disable and Enable
(EWDS/EWEN)
HIGH-Z
1
EWDS TIMING
EWEN TIMING
READ TIMING
1
1
1
0
0
0
0
0
An
0
1
•••
0
A0
1
0
Dx
X
X
•••
3.7
The READ instruction outputs the serial data of the
addressed memory location on the DO pin. A dummy
zero bit precedes the 8-bit (93LC66A) or 16-bit
(93LC66B) output string. The output data bits will tog-
gle on the rising edge of the CLK and are stable after
the specified time delay (T
sible when CS is held high. The memory data will auto-
matically cycle to the next register and output
sequentially.
•••
•••
D0
Dx
READ
X
X
•••
T
T
CSL
CSL
D0
 1998 Microchip Technology Inc.
PD
Dx
). Sequential read is pos-
•••
D0