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4.5 I/O Ports
(P00-P03, P10-P13, P20-P23 and P40-P43)
4.5.1 Configuration of I/O ports
The S1C63616 is equipped with 16 bits of I/O ports (P00–P03, P10–P13, P20–P23 and P40–P43) in which the
input/output direction can be switched with software.
Figure 4.5.1.1 shows the structure of an I/O port.
Note: If an output terminal (including a special output terminal) of this IC is used to drive an external com-
ponent that consumes a large amount of current such as a bipolar transistor, design the pattern of
traces on the printed circuit board so that the operation of the external component does not affect
the IC power supply. Refer to <Output Terminals> in Section 5.3, "Precautions on Mounting", for
more information.
Each I/O port terminal provides an internal pull-down resistor. The mask option allows selection of the
pull-down resistor to be connected or disconnected in 1-bit units.
When "Use" is selected by mask option, the port suits input from the push switch, key matrix, and so forth.
When "Not use" is selected, the port can be used for slide switch input and interfacing with other LSIs.
The P10 and P11 I/O ports can also be used as the Run/Stop and Lap direct inputs for the stopwatch timer.
The P12 and P41–P43 ports can also be used as the event counter inputs for the programmable timer.
The I/O port terminals P00–P03, P13, P20–P23 are shared with the R/f converter input/output terminals,
serial interface input/output terminals and special output (BZ, FOUT, TOUT_A) terminals. The software
can select the function to be used.
At initial reset, these terminals are all set to the I/O port.
Table 4.5.1.1 shows the setting of the input/output terminals by function selection.
Pull-down control
register (PUL)
I/O control
register (IOC)
Data
register
*1
Input
control
*2
∗1: During output mode
∗2: During input mode
Fig. 4.5.1.1 Structure of I/O port
SIC63616-(Rev. 1.0) NO. P44
V
DD
Pxx
Mask
option
V
SS
3240-0412
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