at45db021b ATMEL Corporation, at45db021b Datasheet - Page 9

• Manufacturer Part Number: at45db021b
• Description: At45db021b 2-megabit 2.7-volt Only Dataflash
• Manufacturer: ATMEL Corporation

5.4
Table 5-3.
1937J–DFLSH–9/05
Command
Continuous Array Read
Main Memory Page Read
Buffer 1 Read
Buffer 2 Read
Status Register Read
Operation Mode Summary
Read Commands
The modes described can be separated into two groups – modes which make use of the Flash
memory array (Group A) and modes which do not make use of the Flash memory array (Group
B).
Group A modes consist of:
Group B modes consist of:
If a Group A mode is in progress (not fully completed), then another mode in Group A should not
be started. However, during this time in which a Group A mode is in progress, modes in Group B
can be started.
This gives the Serial DataFlash the ability to virtually accommodate a continuous data stream.
While data is being programmed into main memory from buffer 1, data can be loaded into buffer
2 (or vice versa). See application note AN-4 (“Using Atmel’s Serial DataFlash”) for more details.
1. Main Memory Page Read
2. Main Memory Page to Buffer 1 (or 2) Transfer
3. Main Memory Page to Buffer 1 (or 2) Compare
4. Buffer 1 (or 2) to Main Memory Page Program with Built-in Erase
5. Buffer 1 (or 2) to Main Memory Page Program without Built-in Erase
6. Page Erase
7. Block Erase
8. Main Memory Page Program through Buffer
9. Auto Page Rewrite
1. Buffer 1 (or 2) Read
2. Buffer 1 (or 2) Write
3. Status Register Read
SCK Mode
Inactive Clock Polarity Low or High
SPI Mode 0 or 3
Inactive Clock Polarity Low or High
SPI Mode 0 or 3
Inactive Clock Polarity Low or High
SPI Mode 0 or 3
Inactive Clock Polarity Low or High
SPI Mode 0 or 3
Inactive Clock Polarity Low or High
SPI Mode 0 or 3
AT45DB021B
Opcode
D2H
D4H
D6H
D7H
E8H
68H
52H
54H
56H
57H
9