LE25S20FD

www.onsemi.com

12

8. Chip Erase

Chip erase is an operation that sets the memory cell data in all the sectors to "1". "Figure 13 Chip Erase" shows the

timing waveforms, and Figure 20 shows a chip erase flowchart. The chip erase command consists only of the first

bus cycle, and it is initiated by inputting (60h) or (C7h). After the command has been input, the internal erase

operation starts from the rising CS edge, and it ends automatically by the control exercised by the internal timer.

Erase end can also be detected using status register RDY.

Figure 13 Chip Erase

9. Page Program

Page program is an operation that programs any number of bytes from 1 to 256 bytes within the same sector page

(page addresses: A17 to A8). Before initiating page program, the data on the page concerned must be erased using

small sector erase, sector erase, or chip erase. "Figure 14 Page Program" shows the page program timing

waveforms, and Figure 21 shows a page program flowchart. After the falling CS, edge, the command (02H) is

input followed by the 24-bit addresses. Addresses A17 to A0 are valid. The program data is then loaded at each

rising clock edge until the rising CS edge, and data loading is continued until the rising CS edge. If the data loaded

has exceeded 256 bytes, the 256 bytes loaded last are programmed. The program data must be loaded in 1-byte

increments, and the program operation is not performed at the rising CS edge occurring at any other timing.

Figure 14 Page Program

SCK

SI

High Impedance

SO

CS

tCHE

Self-timed

Erase Cycle

60h / C7h

0

1

2

3

4

5

6

7

Mode3

Mode0

8CLK

MSB

tPP

Self-timed

Program Cycle

SCK

SI

High Impedance

SO

CS

PD

Add.

Add.

02h

Add.

PD

15

0

1

2

3

4

5

6

7

8

23

16

24

31 32

39 40

47

Mode3

Mode0

8CLK

PD

2079

MSB