UPD17073 NEC, UPD17073 Datasheet - Page 61

• Manufacturer Part Number: UPD17073
• Description: 4-BIT SINGLE-CHIP MICROCONTROLLER WITH HARDWARE FOR DIGITAL TUNING SYSTEM
• Manufacturer: NEC

10.2.4 To use I/O port in input mode
corresponding to each pin.
when the low level is input to the pin.
input mode, the contents of the output latch are rewritten.
10.2.5 To use I/O Port in output mode
to each pin.
the contents of the output latch are read.
10.2.6 I/O port status on reset
(1) On power-ON reset
(2) On CE reset
(3) On execution of clock stop instruction
(4) In halt status
The port pin to be used in the input mode is selected by the I/O select register of each port.
The pin set in the input mode is floated (Hi-Z) and waits for the input of an external signal.
The input data can be read by executing a read instruction (such as SKT instruction) to the port register
“1” is read from the port register when the high level is input to the corresponding pin, and “0” is read from the register
If a write instruction (such as MOV instruction) is executed to the port register corresponding to a port set in the
The port pin to be set in the output mode is selected by the I/O select register corresponding to the port.
The pin set in the output mode outputs the contents of the output latch.
The output data is set by executing a write instruction (such as MOV instruction) to the port register corresponding
To output the high level to each pin, “1” is written to the port register, and to output the low level, “0” is written.
The port pin can be floated (Hi-Z) by setting it in the input mode.
If a read instruction (such as SKT) is executed to the port register corresponding to a port set in the output mode,
All the ports are set in the input mode.
The contents of the output latch become 0.
All the ports are set in the input mode.
The contents of the output latch are retained.
All the ports are set in the input mode.
The contents of the output latch are retained.
Increasing current consumption can be prevented due to noise of the input buffer, by using the RESET signal,
as described in 10.2.1.
The previous status is retained.
PD17072,17073
61