MC80F0804D View Datasheet(PDF) - Unspecified

Part Name

Description

Manufacturer

MC80F0804D

8-BIT SINGLE-CHIP MICROCONTROLLERS

Unspecified 

MC80F0704/0708/0804/0808

9. I/O PORTS

The MC80F0704/0708/0804/0808 has three ports (R0, R1 and

R3). These ports pins may be multiplexed with an alternate func-

tion for the peripheral features on the device. All port can drive

maximum 20mA of high current in output low state, so it can di-

rectly drive LED device.

All pins have data direction registers which can define these ports

as output or input. A “1” in the port direction register configure

the corresponding port pin as output. Conversely, write “0” to the

corresponding bit to specify it as input pin. For example, to use

the even numbered bit of R0 as output ports and the odd num-

bered bits as input ports, write “55H” to address 0C1H (R0 port

direction register) during initial setting as shown in Figure 9-1 .

All the port direction registers in the MC80F0704/0708/0804/

0808 have 0 written to them by reset function. On the other hand,

its initial status is input.

9.1 R0 and R0IO register

R0 is an 8-bit CMOS bidirectional I/O port (address 0C0H). Each

I/O pin can independently used as an input or an output through

the R0IO register (address 0C1H). When R00 through R07 pins

are used as input ports, an on-chip pull-up resistor can be connect-

WRITE “55H” TO PORT R0 DIRECTION REGISTER

0C0H

0C1H

0C2H

0C3H

R0 data

R0 direction

R1 data

R1 direction

0 1 0 1 0 1 0 1 BIT

76543210

I O I O I O I O PORT

76543210

I: INPUT PORT

O: OUTPUT PORT

Figure 9-1 Example of port I/O assignment

ed to them in 1-bit units with a pull-up selection register 0 (PU0).

Each I/O pin of R0 port can be used to open drain output port by

setting the corresponding bit of the open drain selection register

0 (R0OD).

R0 Data Register

ADDRESS: 0C0H

RESET VALUE: 00H

R0

R07 R06 R05 R04 R03 R02 R01 R00

ADDRESS: 0F8H

RESET VALUE: 0000 0000B

PSR0 PWM3OE PWM1OE EC1E EC0E INT3E INT2E INT1E INT0E

R0 Direction Register

R0IO

Input / Output data

ADDRESS: 0C1H

RESET VALUE: 00H

R0 Pull-up

Selection Register

PU0

Port Direction

0: Input

1: Output

ADDRESS: 0FCH

RESET VALUE: 00H

R0 Open Drain

Selection Register

R0OD

Pull-up Resister Selection

0: Disable

1: Enable

ADDRESS: 0C8H

RESET VALUE: 00H

Open Drain Resister Selection

0: Disable

1: Enable

Port / INT Selection

0: R11, R12, R03, R00

1: INT0, INT1,INT2, INT3

Port / EC Selection

0: R04, R07

1: EC0, EC1

Port / PWM Selection

0: R10, R11

1: PWM1O, PWM3O

ADDRESS: 0F9H

RESET VALUE: ---- 0000B

PSR1 -

-

-

- AVREFS BUZOE T2OE T0OE

Port / TO Selection

0: R04, R07

1: EC0, EC1

R12/BUZO Selection

0: R12 port (Turn off buzzer)

1: BUZO port (Turn on buzzer)

R10 / AVREF Selection

0: R10 port

1: AVREF port

Figure 9-2 R0 Port Register

In addition, Port R0 is multiplexed with various alternate func-

tions. The port selection register PSR0 (address 0F8H) and PSR1

(address 0F9H) control the selection of alternate functions such as

external interrupt 3 (INT3), external interrupt 2 (INT2), event

counter input 0 (EC0), timer 0 output (T0O), timer 2 output

(T2O) and event counter input 1 (EC1). When the alternate func-

38

October 31, 2011 Ver 1.03

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