
S1C8F360 TECHNICAL MANUAL
EPSON
61
5 PERIPHERAL CIRCUITS AND THEIR OPERATION (I/O Ports)
5.7 I/O Ports (P ports)
5.7.1 Configuration of I/O ports
The S1C8F360 is equipped with 16 bits of I/O ports
(P00–P07, P10–P17). The configuration of these I/O
ports will vary according to the bus mode as shown
below.
Table 5.7.1.1 Configuration of I/O ports
Terminal
P00
P01
P02
P03
P04
P05
P06
P07
P10
P11
P12
P13
P14
P15
P16
P17
I/O port P00
I/O port P01
I/O port P02
I/O port P03
I/O port P04
I/O port P05
I/O port P06
I/O port P07
Bus mode
Expanded 64K Expanded 512K
Single chip
Data bus D0
Data bus D1
Data bus D2
Data bus D3
Data bus D4
Data bus D5
Data bus D6
Data bus D7
I/O port P10 (SIN)
I/O port P11 (SOUT)
I/O port P12 (SCLK)
I/O port P13 (SRDY)
I/O port P14 (CMPP0/AD4)
I/O port P15 (CMPM0/AD5)
I/O port P16 (CMPP1/AD6)
I/O port P17 (CMPM1/AD7)
With respect to the data bus, see "5.2 System
Controller and Bus Control".
Figure 5.7.1.1 shows the structure of an I/O port.
Input
control
VDD
VSS
Data
bus
Pxx
Data
register
I/O control
register
*1
*2
*1: During output mode
*2: During input mode
*3: P14–P17 have no pull-up resistor
*3
Fig. 5.7.1.1 Structure of I/O port
I/O port can be set for input or output mode in one
bit unit. These settings are performed by writing
data to the I/O control registers.
I/O port terminals P10–P13 and P14–P17 are shared
with serial interface input/output terminal and
analog comparator/AD input terminals,
respectively. The function of each terminals is
switchable in software. With respect to serial
interface, analog comparator and A/D converter,
see "5.8 Serial Interface", "5.14 Analog Comparator"
and "5.15 A/D Converter", respectively.
The data registers and I/O control registers of I/O
ports set for data bus and serial interface output
terminals use are usable as general purpose
registers with read/write capabilities which do not
affect I/O activities of the terminal.
The same as above, the I/O control register of I/O
port set for serial interface input terminal use is
usable as general purpose register.
I/O ports P00–P07 and P10–P13 are equipped with
a pull-up resistor which goes ON in the input
mode.
When changing the port terminal from LOW level
to HIGH with the built-in pull-up resistor, a delay
in the waveform rise time will occur depending on
the time constant of the pull-up resistor and the
load capacitance of the terminal. It is necessary to
set an appropriate wait time for introduction of an
I/O port. Make this wait time the amount of time
or more calculated by the following expression.
Wait time = RIN x (CIN + load capacitance on the
board) x 1.6 [sec]
RIN: Pull up resistance Max. value
CIN: Terminal capacitance Max. value
5.7.2 Mask option
In the S1C8F360, the pull-up option for the P00–P07
and P10–P13 ports is fixed at "with pull-up
resistor". The P14–P17 ports have no pull-up
resistor.