25AA080A View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

25AA080A

8K SPI™ Bus Serial EEPROM

Microchip Technology 

25XX080A/B

2.5 Read Status Register Instruction

(RDSR)

The Read Status Register instruction (RDSR) provides

access to the Status Register. The Status Register may

be read at any time, even during a write cycle. The

Status Register is formatted as follows:

TABLE 2-2: STATUS REGISTER

7

654 3

2

1

0

W/R – – – W/R W/R R

R

WPEN X X X BP1 BP0 WEL WIP

W/R = writable/readable. R = read-only.

The Write-In-Process (WIP) bit indicates whether the

25XX080A/B is busy with a write operation. When set

to a ‘1’, a write is in progress, when set to a ‘0’, no write

is in progress. This bit is read-only.

The Write Enable Latch (WEL) bit indicates the status

of the write enable latch and is read only. When set to

a ‘1’, the latch allows writes to the array or the Status

Register, when set to a ‘0’, the latch prohibits writes to

the array or the Status Register. The state of this bit can

always be updated via the WREN or WRDI commands

regardless of the state of write protection on the Status

Register. These commands are shown in Figure 2-4

and Figure 2-5.

The Block Protection (BP0 and BP1) bits indicate

which blocks are currently write-protected. These bits

are set by the user issuing the WRSR instruction, which

is in Figure 2-7. These bits are nonvolatile and are

shown in Table 2-3.

See Figure 2-6 for the RDSR timing sequence.

FIGURE 2-6: READ STATUS REGISTER TIMING SEQUENCE (RDSR)

CS

SCK

SI

SO

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

instruction

0 00 00 1 01

high-impedance

data from Status Register

7 6 54 3 2 10

DS21808B-page 10

 2003 Microchip Technology Inc.

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