Datasheet

DEM 16215 SBH-PW-N Product specification
10. INTERFACE WITH MPU IN BUS MODE
1). Interface with 8-bit MPU
When interface data length are 8-bits , transfer is performed all at once through 8 ports. From DB0 to DB7 .
An Example of timing sequence is shown below .
2) Interface with 4-bits MPU
When interfacing data length aref 4-bits , only 4 ports, from DB4 to DB7 , are used as data bus .
At first, higher 4-bit (in case of 8-bit bus mode, the contents of DB4~DB7) are transferred, and then the lower 4-bit
(in case of 8-bit bus mode, the contents of DB0~DB3) are transferred. So transfer is performed in two parts. Busy
Flag outputs"1" after the second transfer are ended.
Example of timing sequence is shown below .
RS
R/W
E
internal Singnal
DB7
internal Operation
Data
Data
Busy Busy
No
Busy
instruction
Busy Flag
check
instruction
Busy Flag
check
Busy Flag
check
RS
R/W
E
internal Singnal
DB7
internal Operation
Busy
No
Busy
instruction
Busy Flag check
instruction
Busy Flag Check
Example of 8-bit bus mode timing
Example of 4-bit bus mode timing
Diagram
VERSION : 3 PAGE: 11