LC87F76C8A

No.A0858-10/24

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)

P00 to P07

each bit

2

N-channel open drain

No

1

CMOS

Programmable

P10 to P17

each bit

2

N-channel open drain

Programmable

1

CMOS

Programmable

P30 to P31

each bit

2

N-channel open drain

Programmable

P70

-

No

N-channel open drain

Programmable

P71 to P73

-

No

CMOS

Programmable

P80 to P87

-

No

N-channel open drain

No

S0/PA0 to S31/PD7

-

No

CMOS

Programmable

COM0/PL0 to COM3/PL3

-

No

Input only

No

V1/PL4 to V3/PL6

-

No

Input only

No

XT1

-

No

Input only

No

XT2

-

No

Output for 32.768kHz crystal oscillator (Nch-open

drain when in general-purpose output mode)

No

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

*1 Connect the IC as shown below to minimize the noise input to the VDD1 pin.

Be sure to electrically short the VSS1, VSS2, and VSS3 pins.

*2 The internal memory is sustained by VDD1. If none of VDD2 and VDD3 are backed up, the high level output at the

ports are unstable in the HOLD backup mode, allowing through current to flow into the input buffer and thus

shortening the backup time.

Make sure that the port outputs are held at the low level in the HOLD backup mode.

Power

supply

LSI

VDD1

For backup *2

VDD2

VDD3

VSS3

VSS2

VSS1