
S1C88409 TECHNICAL MANUAL
EPSON
79
CHAPTER 5: PERIPHERAL CIRCUITS AND OPERATION (I/O Ports)
When the serial interface is used
(P10–P17)
The S1C88409 has a serial interface built-in. The
serial interface uses the following terminals and
unused terminals can be used as a general-purpose
I/O ports.
Transfer mode
Terminals used for serial I/F
(P10–P17)
Asynchronous
P10, P11 (or P14, P15)
Clock sync. slave
P10–P13 (or P14–P17)
Clock sync. master
P10–P12 (or P14–P16)
IrDA interface
P14, P15
The data register and the I/O control register of
the port which is assigned to the serial interface
can be used as a general-purpose register that does
not affect the input/output.
Refer to Section 5.14, "Serial Interface", for setting
of the serial interface.
When the touch panel controller is used
(P20–P23)
The S1C88409 has a built-in touch panel controller.
When the touch panel controller is used, the P20–
P23 terminals work as the touch panel control
signal output terminals (BYH, BYL, BXH, BXL).
Note: When the touch panel function is selected
by mask option, the P20–P23 terminals are
configured as follows at initial reset:
P20 (BYH)
High level
P21 (BYL)
Low level
P22 (BXH)
High level
P23 (BXL)
Low level
The P20–P23 terminals are disconnected
from the I/O control and data registers, and
are controlled from the touch panel control-
ler. Thus it is unnecessary to configure
these terminals by software. The I/O control
and data registers for these ports can be
used as general-purpose registers.
Refer to Section 5.17, "Touch Panel Controller" for
setting the touch panel controller.
Since the touch panel controller uses the A/D
converter, the P3x terminals used for inputting
analog signals cannot be used as I/O ports.
Table 5.8.2.1 Terminal function list
Terminal
P00
P01
P02
P03
P04
P05
P06
P07
P10
P11
P12
P13
P14
P15
P16
P17
P20
P21
P22
P23
P30
P31
P32
P33
P34
P35
P36
P37
I/O port
P00
P01
P02
P03
P04
P05
P06
P07
P10
P11
P12
P13
P14
P15
P16
P17
P20
P21
P22
P23
P30
P31
P32
P33
P34
P35
P36
P37
I/O
Standard function
Data bus for external memory
(Expanded mode)
Serial I/F data input
Serial I/F data output
Serial I/F clock input/output
Serial I/F ready output
Serial I/F data input/IR input
Serial I/F data output/IR output
Serial I/F clock input/output
Serial I/F ready output
Touch panel controller control signal output
A/D converter analog signal input
A/D converter analog signal input or
D/A converter analog signal output
A/D converter analog signal input or
D/A converter analog signal output
D0
D1
D2
D3
D4
D5
D6
D7
SIN
SOUT
SCLK
SRDY
SIN/IRI
SOUT/IRO
SCLK
SRDY
BYH
BYL
BXH
BXL
AD0
AD1
AD2
AD3
AD4
AD5
AD6
DA0
AD7
DA1
I/O
I
O
I/O
O
I
O
I/O
O
I
O
I
O
Sub-function