UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 63

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

(4) P30 to P37 (Port 3) ... 3-state input/output
Port 3 is an 8-bit input/output port with an output latch. Input/output can be specified bit-wise by means of the port 3 mode
register (PM3). Each pin incorporates a software programmable pull-up resistor.
In addition to its function as an input/output port, port 3 also has various dual-function control signal pin functions.
The operating mode can be specified bit-wise by means of the port 3 mode control register (PMC3), as shown in
Table 2-3. The pin level of any pin can always be read or tested regardless of the dual-function pin operation.
When RESET is input, port 3 is set as an input port (output high-impedance state), and the output latch contents are
undefined.
(iii) CI (Clock Input)
(iv) ASCK (Asynchronous Serial Clock)
(v) SCK1 (Serial Clock)
(vi) SI0 (Serial Input 0)
The timer/counter 2 external clock input pin.
The external baud rate clock input pin.
The serial clock input/output pin (in 3-wire serial I/O1 mode).
The serial data input pin (in 3-wire serial I/O0 mode).
Setting Condition
P30
P31
P32
P33
P34
P35
P36
P37
Mode
Table 2-3 Port 3 Operating Modes (n = 0 to 7)
Input/output port
CHAPTER 2 PIN FUNCTIONS
PMC3n = 0
Port Mode
RxD input / SI1 input
TxD output / SO1 output
SCK0 input/output
SO0 output / SB0 input/output
TO0 output
TO1 output
TO2 output
TO3 output
PMC3n = 1
Control Signal Input/Output Mode
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