27

3638F–DFLASH–4/08

AT45DB021D

Note:

Based on JEDEC publication 106 (JEP106), Manufacturer ID data can be comprised of any number of bytes. Some manufacturers may have

Manufacturer ID codes that are two, three or even four bytes long with the first byte(s) in the sequence being 7FH. A system should detect code

7FH as a “Continuation Code” and continue to read Manufacturer ID bytes. The first non-7FH byte would signify the last byte of Manufacturer ID

data. For Atmel (and some other manufacturers), the Manufacturer ID data is comprised of only one byte.

14.2

Operation Mode Summary

The commands described previously can be grouped into four different categories to better

describe which commands can be executed at what times.

Group A commands consist of:

1.

Main Memory Page Read

2.

Continuous Array Read

3.

Read Sector Protection Register

4.

Read Sector Lockdown Register

5.

Read Security Register

Group B commands consist of:

1.

Page Erase

2.

Block Erase

3.

Sector Erase

4.

Chip Erase

5.

Main Memory Page to Buffer Transfer

6.

Main Memory Page to Buffer Compare

7.

Buffer to Main Memory Page Program with Built-in Erase

8.

Buffer to Main Memory Page Program without Built-in Erase

9.

Main Memory Page Program through Buffer

10. Auto Page Rewrite

Group C commands consist of:

1.

Buffer Read

2.

Buffer Write

3.

Status Register Read

4.

Manufacturer and Device ID Read

Group D commands consist of:

1.

Erase Sector Protection Register

2.

Program Sector Protection Register

3.

Sector Lockdown

4.

Program Security Register

If a Group A command is in progress (not fully completed), then another command in Group A,

B, C, or D should not be started. However, during the internally self-timed portion of Group B

commands 1 through 4, any command in Group C can be executed. During the internally self-

timed portion of Group B commands 5 through 10, only Group C commands 3 and 4 can be exe-