7

1937J–DFLSH–9/05

AT45DB021B

5.2.4

Page Erase

The optional Page Erase command can be used to individually erase any page in the main

memory array allowing the Buffer to Main Memory Page Program without Built-in Erase com-

mand to be utilized at a later time. To perform a Page Erase, an opcode of 81H must be loaded

into the device, followed by five reserved bits, ten address bits (PA9 -PA0), and nine don’t care

bits. The ten address bits are used to specify which page of the memory array is to be erased.

When a low-to-high transition occurs on the CS pin, the part will erase the selected page to 1s.

The erase operation is internally self-timed and should take place in a maximum time of t

ing this time, the status register will indicate that the part is busy.

5.2.5

Block Erase

A block of eight pages can be erased at one time allowing the Buffer to Main Memory Page Pro-

gram without Built-in Erase command to be utilized to reduce programming times when writing

large amounts of data to the device. To perform a Block Erase, an opcode of 50H must be

loaded into the device, followed by five reserved bits, seven address bits (PA9 -PA3), and 12

don’t care bits. The seven address bits are used to specify which block of eight pages is to be

erased. When a low-to-high transition occurs on the CS pin, the part will erase the selected

block of eight pages to 1s. The erase operation is internally self-timed and should take place in a

maximum time of t

5.2.6

Main Memory Page Program through Buffer

This operation is a combination of the Buffer Write and Buffer to Main Memory Page Program

with Built-in Erase operations. Data is first shifted into buffer 1 or buffer 2 from the SI pin and

then programmed into a specified page in the main memory. To initiate the operation, an 8-bit

opcode (82H for buffer 1 or 85H for buffer 2) must be followed by the five reserved bits and 20

address bits. The 10 most-significant address bits (PA9-PA0) select the page in the main mem-

ory where data is to be written, and the next nine address bits (BFA8-BFA0) select the first byte

in the buffer to be written. After all address bits are shifted in, the part will take data from the SI

pin and store it in one of the data buffers. If the end of the buffer is reached, the device will wrap

around back to the beginning of the buffer. When there is a low-to-high transition on the CS pin,

the part will first erase the selected page in main memory to all 1s and then program the data

stored in the buffer into the specified page in the main memory. Both the erase and the program-

ming of the page are internally self-timed and should take place in a maximum of time t

During this time, the status register will indicate that the part is busy.

Table 5-2.

Block Erase Addressing

PA9

PA8

PA7

PA6

PA5

PA4

PA3

PA2

PA1

PA0

Block

000

00

00

X

X

X

0

000

00

01

X

X

X

1

000

00

10

X

X

X

2

000

00

11

X

X

X

3

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

•

111

11

00

X

X

X

124

111

11

01

X

X

X

125

111

11

10

X

X

X

126

111

11

11

X

X

X

127