A25L20P/A25L10P/A25L05P Series
Fast Read Dual Input-Output (BBh)
The Fast Read Dual Input-Output (BBh) instruction is similar
to the Fast_Read (0Bh) instruction except the data is input
and output on two pins, DO and DIO, instead of just DO. This
frequency of fC (See AC Characteristics). This is
accomplished by adding four “dummy” clocks after the 24-bit
address as shown in figure 11. The dummy clocks allow the
device’s internal circuits additional time for setting up the
initial address. The input data during the dummy clocks is
“don’t care”. However, the DIO and DO pins should be
high-impedance prior to the falling edge of the first data out
clock.
allows
data
to
be
transferred
from
the
A25L20P/A25L10P/A25L05P at twice the rate of standard
SPI devices.
Similar to the Fast Read instruction, the Fast Read Dual
Output instruction can operate at the highest possible
Figure 11. FAST_READ_DUAL_INPUT-OUTPUT Instruction Sequence and Data-Out Sequence
S
6
0
1
2
3
4
5
7
8
9 10
16 17 18 19
C
DIO
DO
Instruction
24-Bit Address
22
18
4
2
3
0
1
20
6
MSB
High Impedance
23
19
5
7
21
S
C
20 21 22 23 24 25 26 27 28
Dummy
29 30 31 32 33 34 35
DIO switches from input to output
Byte
3
2
1
0
6
4
2
0
6
4
2
0
6
4
2
0
1
6
7
4
5
2
3
0
1
6
7
4
5
2
3
0
1
DIO
DO
3
1
3
7
5
3
1
5
7
5
7
7
MSB
MSB
MSB
MSB
Data Out 2
Data Out 3
Data Out 4
Data Out 5
Data Out 1
Note: Address bits A23 to A18 are Don’t Care, for A25L20P.
Address bits A23 to A17 are Don’t Care, for A25L10P.
Address bits A23 to A16 are Don’t Care, for A25L05P
(August, 2007, Version 1.0)
19
AMIC Technology Corp.