A25L16P 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
allows data to be transferred from the A25L16P at twice the
rate of standard SPI devices.
(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.
Similar to the Fast Read instruction, the Fast Read Dual Output
instruction can operate at the highest possible frequency of fC
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 A21 are Don’t Care.
PRELIMINARY (March, 2006, Version 0.2)
16
AMIC Technology Corp.
AMICC [ AMIC TECHNOLOGY ]
