ST7628
7. FUNCTIONAL DESCRIPTION
7.1 MICROPROCESSOR INTERFACE
Chip Select Input
/CS pin is chip selection. The ST7628 is active when /CS=L. In serial interface mode, the internal shift register and the
counter are reset when /CS=H.
7.1.1 Selecting Parallel / Serial Interface
ST7628 has six types of interface with an MPU, which are two serial and four parallel interfaces. This parallel or serial
interface is determined by IF pin as shown in Table 7.1.1.
Table 7.1.1Parallel / Serial Interface Mode
I/F Mode
Pin Assignment
I/F Description
Used
Data Bus
D7 ~ D2
D7 ~ D2
D7 ~ D2
D7 ~ D2
--
IF3 IF2 IF1
/CS
80 serial 16-bit parallel /CS
80 serial 8-bit parallel /CS
68 serial 16-bit parallel /CS
A0
E_RD
RW_WR D15 to D8
D1
D0
H
H
H
H
L
H
H
L
L
H
H
H
L
H
L
H
L
A0
A0
A0
A0
/RD
/RD
E
E
--
/WR
/WR
R/W
R/W
--
D15 ~ D8
D1
D1
D1
D1
A0
--
D0
D0
D0
D0
SI
--
D15 ~ D8
68 serial 8-bit parallel
8-bit SPI mode (4 line)
9-bit SPI mode (3 line)
/CS
/CS SCL
/CS SCL
--
--
--
L
--
--
--
SI
NOTE: When these pins are set to any other combination, A0, E_RD and RW_WR inputs are disabled and D0 to D15 are
to be high impedance.
7.1.2 8-bit or 16-bit Parallel Interface
The ST7628 identifies the type of the data bus signals according to the combination of A0, /RD (E) and /WR (W/R) signals,
as shown in Table 7.1.2.
Table 7.1.2Parallel Data Transfer
Common
6800-series
R/W
8080-series
/RD
Description
A0
H
E
/WR
H
H
H
L
↑
↑
↓
↓
↓
↓
Register status read
Display data read out
Instruction write
H
H
L
↑
H
H
H
L
↑
Display data write
Ver 1.4
17/213
2008/08
SITRONIX [ SITRONIX TECHNOLOGY CO., LTD. ]
