CY14B101P-SFXI(2012) Ver la hoja de datos (PDF) - Cypress Semiconductor

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Fabricante

CY14B101P-SFXI
(Rev.:2012)

1-Mbit (128 K × 8) Serial SPI nvSRAM with Real Time Clock

Cypress Semiconductor 

CY14B101P

Figure 6. Read Status Register (RDSR) Instruction Timing

CS

SCK

0 1 2 3 4 5 67 01 2 3 4 5 67

SI

0 0 0 0 01 0 1 0

MSB

LSB

SO

HI-Z

D7 D6 D5 D4 D3 D2 D1 D0

MSB

Data

LSB

Figure 7. Write Status Register (WRSR) Instruction Timing

CS

SCK

01 23 4 5 6 701 2 3 4 5 6 7

Opcode

Data in

SI

0 0 0 0 0 0 0 1 D7 X X X D3 D2 X X

MSB

LSB

SO

HI-Z

Write Protection and Block Protection

CY14B101P provides features for both software and hardware

write protection using WRDI instruction and WP. Additionally, this

device also provides block protection mechanism through BP0

and BP1 pins of the Status Register.

The Write Enable and Disable status of the device is indicated

by WEN bit of the Status Register. The write instructions (WRSR,

WRITE, and WRTC) and nvSRAM special instruction (STORE,

RECALL, ASENB, ASDISB) need the write to be enabled (WEN

bit = 1) before they can be issued.

Write Enable (WREN) Instruction

On power-up, the device is always in the write disable state. The

following WRITE, WRSR, WRTC, or nvSRAM special instruction

must therefore be preceded by a Write Enable instruction. If the

device is not write enabled (WEN = ‘0’), it ignores the write

instructions and returns to the standby state when CS is brought

HIGH. A new CS falling edge is required to re-initiate serial

communication. The instruction is issued following the falling

edge of CS. When this instruction is used, the WEN bit of Status

Register is set to ‘1’. WEN bit defaults to ‘0’ on power-up.

Note After completion of a write instruction (WRSR, WRITE, or

WRTC) or nvSRAM special instruction (STORE, RECALL,

ASENB, ASDISB) instruction, WEN bit is cleared to ‘0’. This is

done to provide protection from any inadvertent writes.

Therefore, WREN instruction must be used before a new write

instruction is issued.

Figure 8. WREN Instruction

CS

SCK

01 234567

SI

00000110

SO

HI-Z

Document Number: 001-44109 Rev. *M

Page 10 of 36

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