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2.7
Write
The
WRITE
instruction is followed by 16 bits (or by 8
bits) of data which are written into the specified
address. After the last data bit is put on the DI pin,
CS must be brought low before the next rising edge
of the CLK clock. This falling edge of CS initiates the
self-timed auto-erase and programming cycle.
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
) and before the entire write cycle is complete.
DO at logical “0” indicates that programming is still in
progress. DO at logical “1” indicates that the register at
the specified address has been written with the data
specified and the device is ready for another
instruction.
The write cycle takes 4 ms per word typical.
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
) and before the entire write cycle is complete.
The ERAL cycle takes (8 ms typical).
2.9
Write All (WRAL)
The
WRAL
instruction will write the entire memory array
with the data specified in the command. The WRAL
cycle is completely self-timed and commences at the
falling edge of the CS. Clocking of the CLK pin is not
necessary after the device has entered the self clock-
ing mode. The WRAL command does include an auto-
matic 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
WRAL
instruction
is ensured at 5V ±10%.
The DO pin indicates the Ready/Busy status of the
device if CS is brought high after a minimum of 250 ns
low (Tcsl).
The WRAL cycle takes 16 ms typical.
2.8
Erase All (ERAL)
The
ERAL
instruction will erase the entire memory array
to the logical “1” state. The ERAL cycle is identical to
the ERASE cycle except for the different opcode. The
ERAL cycle is completely self-timed and commences
at the falling edge of the CS. Clocking of the CLK pin is
not necessary after the device has entered the self
clocking mode. The
ERAL
instruction is ensured at 5V
±10%.
FIGURE 2-1:
READ TIMING
CS
CLK
DI
1
1
0
An
•••
A0
DO
High-Z
0
Dx
•••
D0
Dx
•••
D0
Dx
•••
D0
2004 Microchip Technology Inc.
DS21712B-page 7
MICROCHIP [ MICROCHIP TECHNOLOGY ]
