SC23M28

HANGZHOU SILAN MICROELECTRONICS CO.,LTD

REV:1.0

2006.07.21

Http: www.silan.com.cn

Page 5 of 10

3. Instruction description

3.1

Erase/write operation

1)

Erase or write with protect bit

The write protect bit is active as long as you write the data, and this unit is only readable.

2)

Erase or write without protect bit.

Write the data but not set the protect bit, so this unit can still be erased and written.

3)

Write protect bit with data comparison

When the command is executed, it will compare the data and the content of the destination address

unit, if the contents are the same, then write “0”to the corresponding address unit; if the contents are

different, do nothing.

The chip can execute 3 erase and write operation:

Erase and write (Last 203 clock cycles) (Figure3);

Only Write: used for some bits of 1 byte data change from “1”to “0”(Last 103 clock cycles)(Figure4);

Only Erase: data is FF (Last 103 clock cycles) (Figure4).

If error occurs when erase or write data, I/O port will change from high level to low level at the

raising edge of the third clock cycle. (Figure5).

Figure3 Erase and write time sequence

Figure4 Only Erase or only Write time sequence