AT25DF641A-MH-T ATMEL [ATMEL Corporation], AT25DF641A-MH-T Datasheet - Page 10

• Manufacturer Part Number: AT25DF641A-MH-T
• Description: 64-Mbit 2.7V Minimum Serial Peripheral Interface Serial Flash Memory
• Manufacturer: ATMEL [ATMEL Corporation]

Figure 7-2.
Figure 7-3.
7.2
10
SCK
SO
CS
SI
Dual-Output Read Array
Atmel AT25DF641A [Preliminary]
SCK
Read Array - 0Bh Opcode
Read Array - 03h Opcode
SO
CS
SI
HIGH-IMPEDANCE
MSB
0
0
0
1
0
2
OPCODE
The Dual-Output Read Array command is similar to the standard Read Array command and can
be used to sequentially read a continuous stream of data from the device by simply providing the
clock signal once the initial starting address has been specified. Unlike the standard Read Array
command, however, the Dual-Output Read Array command allows two bits of data to be clocked
out of the device on every clock cycle rather than just one.
The Dual-Output Read Array command can be used at any clock frequency up to the maximum
specified by f
asserted and the opcode of 3Bh must be clocked into the device. After the opcode has been
clocked in, the three address bytes must be clocked in to specify the starting address location of
the first byte to read within the memory array. Following the three address bytes, a single
dummy byte must also be clocked into the device.
After the three address bytes and the dummy byte have been clocked in, additional clock cycles
will result in data being output on both the SO and SIO pins. The data is always output with the
MSB of a byte first, and the MSB is always output on the SO pin. During the first clock cycle, bit
seven of the first data byte will be output on the SO pin while bit six of the same data byte will be
output on the SIO pin. During the next clock cycle, bits five and four of the first data byte will be
output on the SO and SIO pins, respectively. The sequence continues with each byte of data
being output after every four clock cycles. When the last byte (7FFFFFh) of the memory array
has been read, the device will continue reading back at the beginning of the array (000000h). No
delays will be incurred when wrapping around from the end of the array to the beginning of the
array.
0
3
HIGH-IMPEDANCE
MSB
1
0
4
0
0
0
5
1
1
0
6
2
OPCODE
1
0
7
3
MSB
A
0
RDDO
8
4
A
0
9
5
ADDRESS BITS A23-A0
. To perform the Dual-Output Read Array operation, the CS pin must first be
A
1
10 11
6
A
1
7
MSB
A
A
12
8
A
A
9
ADDRESS BITS A23-A0
A
10 11
A
A
29 30
A
12
A
A
A
31 32
MSB
X
X
A
33
29 30
DON'T CARE
X
A
34
X
A
35
31 32
MSB
X
D
36
X
D
37 38
33
DATA BYTE 1
X
D
34
X
D
39
35
MSB
D
D
40
36
D
D
41
37 38
DATA BYTE 1
D
D
42 43
D
D
39 40
MSB
D
D
44
D
D
45
D
46
D
47 48
8693A–DFLASH–8/10
MSB
D
D