LC87F1HC8A

No.A0956-10/27

Port Output Types

The table below lists the types of port outputs and the presence/absence of a pull-up resistor.

Data can be read into any input port even if it is in the output mode.

Port Name

Option selected in

units of

Option type

Output type

Pull-up resistor

1

CMOS

Programmable (Note 1)

P00 to P07

1 bit

2

Nch-open drain

No

1

CMOS

Programmable

P10 to P17

P20 to P27

P30 to P34

1 bit

2

Nch-open drain

Programmable

P70

-

No

Nch-open drain

Programmable

P71 to P73

-

No

CMOS

Programmable

PWM0, PWM1

-

No

CMOS

No

UHD+, UHD-

-

No

CMOS

No

XT1

-

No

Input only

No

XT2

-

No

32.768kHz crystal resonator output (N channel open

drain when in general-purpose output mode)

No

Note 1: Programmable pull-up resistors for port 0 are controlled in 4 bit units (P00 to 03, P04 to 07).

Power Pin Treatment

Connect the IC as shown below to minimize the noise input to the VDD1 pin. and extend the backup period. Be sure to

electrically short the VSS1, VSS2, and VSS3 pins.

Example 1: When the microcontroller is in the backup state in the HOLD mode, the power to sustain the high level of

output ports is supplied by their backup capacitors.

Example 2: The high level output at ports is not sustained and unstable in the HOLD backup mode.

VSS1 VSS2 VSS3

VDD1

VDD2

VDD3

Power

supply

For backup

LSI

LSI

VSS1VSS2VSS3

VDD1

VDD2

VDD3

Power

supply

For backup