AT25DF021-MH-Y Atmel, AT25DF021-MH-Y Datasheet - Page 21

• Manufacturer Part Number: AT25DF021-MH-Y
• Description: IC FLASH 2MBIT 70MHZ 8UDFN
• Manufacturer: Atmel

Specifications of AT25DF021-MH-Y

• Format - Memory: FLASH
• Memory Type: DataFLASH
• Memory Size: 2M (256K x 8)
• Speed: 70MHz
• Interface: SPI, 3-Wire Serial
• Voltage - Supply: 2.7 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 8-UDFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 10-1. Program OTP Security Register
10.2
Figure 10-2. Read OTP Security Register
3677D–DFLASH–04/09
SCK
SO
CS
SI
SCK
SO
CS
Read OTP Security Register
SI
MSB
HIGH-IMPEDANCE
0
0
1
1
MSB
HIGH-IMPEDANCE
1
1
2
OPCODE
0
1
0
3
1
0
The OTP Security Register can be sequentially read in a similar fashion to the Read Array oper-
ation up to the maximum clock frequency specified by f
the CS pin must first be asserted and the opcode of 77h must be clocked into the device. After
the opcode has been clocked in, the three address bytes must be clocked in to specify the start-
ing address location of the first byte to read within the OTP Security Register. Following the
three address bytes, two dummy bytes must be clocked into the device before data can be
output.
After the three address bytes and the dummy bytes have been clocked in, additional clock
cycles will result in OTP Security Register data being output on the SO pin. When the last byte
(00007Fh) of the OTP Security Register has been read, the device will continue reading back at
the beginning of the register (000000h). No delays will be incurred when wrapping around from
the end of the register to the beginning of the register.
Deasserting the CS pin will terminate the read operation and put the SO pin into a high-imped-
ance state. The CS pin can be deasserted at any time and does not require that a full byte of
data be read.
0
4
2
OPCODE
1
1
5
3
1
1
6
4
1
0
7
5
MSB
A
1
8
6
A
1
9
7
ADDRESS BITS A23-A0
MSB
A
10 11
A
ADDRESS BITS A23-A0
8
A
A
9
A
12
A
A
A
29 30
A
29 30
A
A
A
31 32
MSB
A
31 32
D
MSB
X
D
33
DATA IN BYTE 1
X
33
D
34
X
34
D
35
X
DON'T CARE
35
D
36
X
36
D
37 38
X
D
D
39
CLK
X
. To read the OTP Security Register,
X
MSB
D
X
MSB
D
D
DATA IN BYTE n
D
D
DATA BYTE 1
D
D
D
D
D
D
D
D
D
D
D
MSB
D
D
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