at26f004 ATMEL Corporation, at26f004 Datasheet - Page 19

• Manufacturer Part Number: at26f004
• Description: At26f004 4-megabit 2.7-volt Only Serial Firmware Dataflash Memory
• Manufacturer: ATMEL Corporation

10. Status Register Commands
10.1
Table 10-1.
Notes:
3588C–DFLASH–04/06
Bit
3:2
7
6
5
4
1
0
(1)
Read Status Register
1. Bit 7 of the Status Register is the only bit that can be user modified
2. R/W = Readable and writable
Name
RDY/BSY
R = Readable only
SPRL
WPP
SWP
SPM
RES
WEL
Status Register Format
Sector Protection Registers
Locked
Sequential Program Mode
Status
Reserved for future use
Write Protect (WP) Pin
Status
Software Protection Status
Write Enable Latch Status
Ready/Busy Status
The Status Register can be read to determine the device's ready/busy status, as well as the sta-
tus of many other functions such as Hardware Locking and Software Protection. The Status
Register can be read at any time, including during an internally self-timed program or erase
operation.
To read the Status Register, the CS pin must first be asserted and the opcode of 05h must be
clocked into the device. After the last bit of the opcode has been clocked in, the device will begin
outputting Status Register data on the SO pin during every subsequent clock cycle. After the last
bit (bit 0) of the Status Register has been clocked out, the sequence will repeat itself starting
again with bit 7 as long as the CS pin remains asserted and the SCK pin is being pulsed. The
data in the Status Register is constantly being updated, so each repeating sequence will output
new data.
Deasserting the CS pin will terminate the Read Status Register operation and put the SO pin
into a high-impedance state. The CS pin can be deasserted at any time and does not require
that a full byte of data be read.
Type
R/W
R
R
R
R
R
R
(2)
Description
00
01
10
11
0
1
0
1
0
0
1
0
1
0
1
Sector Protection Registers are unlocked (default).
Sector Protection Registers are locked.
Byte programming mode (default).
Sequential Programming mode entered.
Reserved for future use.
WP is asserted.
WP is deasserted.
All sectors are software unprotected.
Some sectors are software protected. Read Sector Protection
Registers.
Reserved for future use.
All sectors are software protected (default).
Device is not write enabled (default).
Device is write enabled.
Device is ready.
Device is busy with an internal operation.
AT26F004
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