X25F087 Datasheet, PDF (4/13 Pages) Xicor Inc. – SPI SerialFlash with Block Lock TM Protection

X25F087
Data Protection
The following circuitry has been included to prevent inad-
vertant programming of data:
• The “Program Enable” latch is reset upon power-up.
• A PREN instruction must be issued to set the “Program
Enable” latch.
• CS must come HIGH at the proper clock count in order
to start a program cycle.
Operational Notes
The X25F087 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 enter
an active state and receive an instruction.
• SO pin is at high impedance.
• The “Program Enable” latch is reset.
Table 1. Instruction Set and Block Lock Protection Byte Definition
Instruction
Format*
Instruction Name and Operation
0000 0110
PREN: Set the Program Enable Latch (Program Enable Operation)
0000 0100
PRDI: Reset the Program Enable Latch (Program Disable Operation)
0000 0001
PROGRAM STATUS Instruction - followed by:
Block Lock Protection Byte: (Figure 1)
0000 0000 --->NO PROTECT: ---------------------------------->None of the Array
0000 0001 --->PROTECT Q1: --- 0000h - 00FFh ---------->Lower Quadrant (Q1)
0000 0010 --->PROTECT Q2: --- 0100h - 01FFh----------->Q2
0000 0011 --->PROTECT Q3: --- 0200h - 02FFh----------->Q3
0000 0100 --->PROTECT Q4: --- 0300h - 03FFh----------->Upper Quadrant (Q4)
0000 0101 --->PROTECT H1: --- 0000h - 01FFh----------->Lower Half of the Array (H1)
0000 0110 --->PROTECT S0: --- 0000h - 000Fh----------->Lower Sector (S0)
0000 0111 --->PROTECT Sn: --- 03F0h - 03FFh----------->Upper Sector (Sn)
0000 0101
READ STATUS: Reads Block Lock Protection & nonvolatile write in progress status on SO Pin
0000 0010
PROGRAM: Program operation followed by address and data
0000 0011
READ: Read operation followed by address
*Instructions are shown with MSB in leftmost position. Instructions are transferred MSB first.
7007 FRM T03
Figure 2. Read Operation Sequence
CS
SCK
SI
0123456789
20 21 22 23 24 25 26 27 28 29 30
READ INSTRUCTION
(1 BYTE)
BYTE ADDRESS (2 BYTE)
15 14
3210
DATA OUT
HIGH IMPEDANCE
SO
76543210
7007 FRM 03
4