ST7070 View Datasheet(PDF) - Sitronix Technology Co., Ltd.
Part Name
Description
MFG CO.
'ST7070' PDF : 51 Pages View PDF
ST7070
Interfacing to the MPU
The ST7070 can send data in either two 4-bit operations or one 8-bit operation or serial operation, thus allowing
interfacing with 4- or 8-bit or serial MPU.
For 4-bit interface data, only four bus lines (DB4 to DB7) are used for transfer. Bus lines DB0 to DB3
are disabled. The data transfer between the ST7070 and the MPU is completed after the 4-bit data has been
transferred twice. As for the order of data transfer, the four high order bits (for 8-bit operation, DB4 to DB7)
are transferred before the four low order bits (for 8-bit operation, DB0 to DB3). The busy flag must be
checked (one instruction) after the 4-bit data has been transferred twice. Two more 4-bit operations then
transfer the busy flag and address counter data.
Example of busy flag check timing sequence
RS
R/W
E
Internal
operation
Functioning
DB7
IR7 IR3
AC
3
Not AC
Busy 3
IR7 IR3
Instruction write Busy flag check Busy flag check Instruction write
Intel 8051 interface
16
COM1 to COM16
P1.0 to P1.3
4
DB4 to DB7
P3.0
P3.1
P3.2
Intel 8051 Serial
RS
R/W
E SEG1 to SEG80 80
ST7070
V1.4
29/51
2009/04/29
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