25LC010A データシートの表示（PDF） - Microchip Technology

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25LC010A

1K-4K SPI Serial EEPROM HighTemp Family Data Sheet

Microchip Technology 

25LCXXXA

3.0 FUNCTIONAL DESCRIPTION

3.1 Principles of Operation

The 25LCXXXA are low-density serial EEPROMs

designed to interface directly with the Serial Peripheral

Interface (SPI) port of many of today’s popular micro-

controller families, including Microchip’s PIC® micro-

controllers. It may also interface with microcontrollers

that do not have a built-in SPI port by using discrete I/

O lines programmed properly in firmware to match the

SPI protocol.

The 25LCXXXA contains an 8-bit instruction register.

The device is accessed via the SI pin, with data being

clocked in on the rising edge of SCK. The CS pin must

be low and the HOLD pin must be high for the entire

operation.

Table 3-1 contains a list of the possible instruction

bytes and format for device operation. All instructions,

addresses, and data are transferred MSB first, LSB

last.

Data (SI) is sampled on the first rising edge of SCK

after CS goes low. If the clock line is shared with other

peripheral devices on the SPI bus, the user can assert

the HOLD input and place the 25LCXXXA in ‘HOLD’

mode. After releasing the HOLD pin, operation will

resume from the point when the HOLD was asserted.

BLOCK DIAGRAM

STATUS

Register

HV Generator

I/O Control

Logic

Memory X

Control

Logic Dec

EEPROM

Array

Page Latches

SI

SO

CS

SCK

HOLD

WP

VCC

VSS

Y Decoder

Sense Amp.

R/W Control

TABLE 3-1: INSTRUCTION SET

Instruction Name Instruction Format

Description

READ

WRITE

WRDI

0000 A8011

0000 A8010

0000 x100

Read data from memory array beginning at selected address

Write data to memory array beginning at selected address

Reset the write enable latch (disable write operations)

WREN

0000 x110

Set the write enable latch (enable write operations)

RDSR

0000 x101

Read STATUS register

WRSR

0000 x001

Write STATUS register

Note: For the 24LC040A device, A8 is the 9th address bit, which is used to address the entire 512 byte array.

For the 24LC020A and 24LC010A devcies, A8 is a don’t care.

x = don’t care.

DS22136B-page 8

Preliminary

© 2009 Microchip Technology Inc.

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