6. FUNCTIONAL DESCRIPTION
S1D15722D01B000 Technical Manual (Rev.1.1)
EPSON
13
6. FUNCTIONAL DESCRIPTION
6.1 MPU Interface
6.1.1 Selecting Interface Type
This IC allows data transfer through 8-bit bi-directional data bus (D7 to D0) or serial data input (SI).
Selecting HIGH or LOW for polarity of P/S pin allows selection of 8-bit parallel data input or serial data input
as shown in Table 6.1.
Table 6.1
P/S
___
CS A0
___
RD
___
WR C86 SI SCL D7
～
D0
HIGH : Parallel input
___
CS A0
___
RD
___
WR
C86
- - D7
～
D0
LOW : Serial input
___
CS A0 - - - SI SCL
(HZ)
- : Set - to HIGH or LOW. HZ is in the state of high impedance.
6.1.2 Parallel interface
When parallel interface is selected (P/S = HIGH), setting the C86 pin to HIGH or LOW allows direct
connection to the MPU bus of either 80 series or 68 series as shown in Table 6.2.
Table 6.2
C86
___
CS A0
___
RD
___
WR D7
～
D0
HIGH : 68 series MPU bus
___
CS A0 E R/
__
W D7
～
D0
LOW : 80 series MPU bus
___
CS A0
___
RD
___
WR D7
～
D0
Data bus signal is identified by combination of A0,
___
RD(E) and
___
WR(R/
__
W) as shown in Table 6.3.
Table 6.3
Common 68 series
80 series
A0 R/
__
W
___
RD
___
WR
Function
1
1
0
1
Display data reading, reads status.
1 0 1 0
Status
data
writing, writes command parameter.
0 0 1 0
Writes
a
command.
6.1.3 Serial Interface
When serial interface is selected (P/S = LOW), the chip is active (
___
CS = LOW) and can accept serial data
input (SI) and serial clock input (SCL). Serial interface is comprised of an 8-bit shift register and 3-bit counter.
Serial data is captured from serial data input pin in order from D7, D6 to D0 on the rising edge of the serial
clock and converted into 8-bit parallel data on the rising edge of the 8th serial clock and then processed.
Whether serial data input is display data, command parameter or command is determined by A0 input. For
A0 = HIGH, display data or command parameter, for A0 = LOW, command. A0 input is read and determined
on the 8xn-th rising edge of the serial clock after the chip goes into the active state.
Using the status read command enables read status and read data, respectively, even when serial interface is
selected. However, it should be noted that the
___
CS signal is handled differently from the time of serial data
input. Read from display data RAM is not enabled. Signal chart of serial interface is shown in Fig.6.1.
