93C46B-ESM Microchip Technology, 93C46B-ESM Datasheet - Page 6

• Manufacturer Part Number: 93C46B-ESM
• Description: 1K 5.0V Microwire Serial EEPROM
• Manufacturer: Microchip Technology

93C46B
3.6
The device powers up in the ERASE/WRITE Disable
(EWDS) state. All programming modes must be pre-
ceded by an Erase/Write Enable (EWEN) instruction.
Once the EWEN instruction is executed, programming
remains enabled until an EWDS instruction 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 operations. Execution of
a READ instruction is independent of both the EWDS
and EWEN instructions.
FIGURE 3-4:
FIGURE 3-5:
FIGURE 3-6:
DS21172D-page 6
CLK
CLK
CS
DO
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
Preliminary
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 16-bit output string. The output
data bits will toggle on the rising edge of the CLK and
are stable after the specified time delay (T
tial read is possible when CS is held high. The memory
data will automatically cycle to the next register and
output sequentially.
•••
•••
D0
Dx
READ
X
X
•••
T
T
CSL
CSL
D0
1997 Microchip Technology Inc.
Dx
•••
D0
PD
). Sequen-