UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 64

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

(5) P40 to P47 (Port 4) ... 3-state input/output
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Port 4 is an 8-bit input/output port with an output latch. Input/output can be specified bit-wise by means of the port 4 mode
register (PM4). Each pin incorporates a software programmable pull-up resistor. This port has direct LED drive capability.
Port 4 also functions as the time division address/data bus (AD0 to AD7) by the memory extension mode register (MM) when
external memory or I/Os are extended.
In the PD784021, this port only functions as the time division address/data bus (AD0 to AD7).
When RESET is input, port 4 is set as an input port (output high-impedance state), and the output latch contents are
undefined.
(a) Port mode
(b) Control signal input/output mode
Each port specified as port mode by the port 3 mode control (PMC3) register can be specified as input/output bit-wise
by means of the port 3 mode register (PM3).
Pins can be set as control pins bit-wise by setting the port 3 mode control (PMC3) register.
(i)
(ii)
(iii) SCK0 (Serial Clock 0)
(iv) SO0 (Serial Output 0)/SB0 (Serial Bus)
(v)
RxD (Receive Data)/SI1 (Serial Input 1)
RxD is the asynchronous serial interface serial data input pin.
SI1 is the serial data input pin (in 3-wire serial I/O1 mode).
TxD (Transmit Data)/SO1 (Serial Output 1)
TxD is the asynchronous serial interface serial data output pin.
SO1 is the serial data output pin (in 3-wire serial I/O1 mode).
The clocked serial interface serial clock input/output pin.
SO0 is the serial data output pin (in 3-wire serial I/O mode), and SB0 is the serial bus input/output pin (in SBI
mode).
TO0 to TO3 (Timer Output)
The timer output pins.
CHAPTER 2 PIN FUNCTIONS