Microchip Technology 93LC56B-I/SN Memory IC SOIC-8 93LC56B-I/SN Data Sheet

Product codes
93LC56B-I/SN
Page of 36
 2003-2011 Microchip Technology Inc.
DS21794G-page 11
93AA56A/B/C, 93LC56A/B/C, 93C56A/B/C
2.9
Write All (WRAL)
The Write All (WRAL) instruction will write the entire
memory array with the data specified in the command.
For 93AA56A/B/C and 93LC56A/B/C devices, after the
last data bit is clocked into DI, the falling edge of CS
initiates the self-timed auto-erase and programming
cycle. For 93C56A/B/C devices, the self-timed auto-
erase and programming cycle is initiated by the rising
edge of CLK on the last data bit. Clocking of the CLK
pin is not necessary after the device has entered the
WRAL cycle. The WRAL command does include an
automatic ERAL cycle for the device. Therefore, the
WRAL
 instruction does not require an ERAL instruction,
but the chip must be in the EWEN status. 
The DO pin indicates the Ready/
Busy
 status of the
device if CS is brought high after a minimum of 250 ns
low (T
CSL
).
V
CC
 must be 
4.5V for proper operation of WRAL. 
FIGURE 2-10:
WRAL TIMING FOR 93AA AND 93LC DEVICES
FIGURE 2-11:
WRAL TIMING FOR 93C DEVICES
Note:
After the Write All cycle is complete,
issuing a Start bit and then taking CS low
will clear the Ready/
Busy
 status from DO.
CS
CLK
DI
DO
H
IGH
-Z
1
0
0
0
1
x
•••
x
Dx
•••
D0
High-Z
Busy
Ready
T
WL
V
CC
 must be 
4.5V for proper operation of WRAL.
T
CSL
T
SV
T
CZ
CS
CLK
DI
DO
H
IGH
-Z
1
0
0
0
1
x
•••
x
Dx
•••
D0
High-Z
Busy
Ready
T
WL
T
CSL
T
SV
T
CZ