93AA66A/B/C, 93LC66A/B/C, 93C66A/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 93AA66A/B/C and 93LC66A/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 93C66A/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
).
Note:
Issuing a Start bit and then taking CS low
will clear the Ready/Busy status from DO.
V
CC
must be
≥
4.5V for proper operation of WRAL.
FIGURE 2-10:
CS
WRAL TIMING FOR 93AA AND 93LC DEVICES
T
CSL
CLK
DI
1
0
0
0
1
x
•••
x
Dx
•••
D0
T
SV
DO
High-Z
T
CZ
Ready
High-Z
Busy
T
WL
V
CC
must be
≥
4.5V for proper operation of WRAL.
FIGURE 2-11:
CS
WRAL TIMING FOR 93C DEVICES
T
CSL
CLK
DI
1
0
0
0
1
x
•••
x
Dx
•••
D0
T
SV
T
CZ
Ready
High-Z
T
WL
DO
High-Z
Busy
©
2005 Microchip Technology Inc.
DS21795C-page 11
MICROCHIP [ MICROCHIP TECHNOLOGY ]
