x25021 Intersil Corporation, x25021 Datasheet - Page 5

• Manufacturer Part Number: x25021
• Description: Spi Serial E2prom With Block Locktm Protection
• Manufacturer: Intersil Corporation

Figure 2. Read Status Register Operation Sequence
X25021
Operational Notes
The X25021 powers-up in the following state:
• The device is in the low power standby state.
• A HIGH to LOW transition on CS is required to
• SO pin is high impedance.
• The “write enable” latch is reset.
Figure 1. Read E
enter an active state and receive an instruction.
SCK
SO
CS
SI
HIGH IMPEDANCE
SCK
2
PROM Array Operation Sequence
SO
CS
SI
0
1
INSTRUCTION
HIGH IMPEDANCE
2
3
0
4
1
INSTRUCTION
5
2
6
3
7
4
8
7
5
6
9
6
5
10 11 12 13 14 15 16 17 18 19 20 21 22
BYTE ADDRESS
5
7
Data Protection
The following circuitry has been included to prevent
inadvertent writes:
• The “write enable” latch is reset upon power-up.
• A WREN instruction must be issued to set the “write
• CS must come HIGH at the proper clock count in
MSB
4
8
7
enable” latch.
order to start a write cycle.
3
9
6
2
10 11 12 13 14
5
DATA OUT
1
4
0
3
MSB
7
2
6
1
6615 ILL F13
5
0
DATA OUT
4
3
2
6615 FHD F14
1
0