LC709004AMJ-AH 查看數據表（PDF） - ON Semiconductor

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LC709004AMJ-AH

I/O-Expander for Microcontroller

ON Semiconductor 

LC709004A

Port Output Types and I/O States

The output type and I/O states of the LC709004A's ports can be selected by configuring the data direction register

(DDR) and data register (DTR). Port data can be taken into the LC709004A only when DDR is set to 0 (Nch-open

drain) and DTR is set to 1 (Nch-Tr OFF). The ports are held high for the other settings of DDR and DTR.

Port Name

P00 to P07

P10 to P17

DDR

0

0

1

1

DTR

1

0

1

0

Output Type

Nch-open drain

Nch-open drain

CMOS

CMOS

Port

Input

Enabled

Disabled (High)

Disabled (High)

Disabled (High)

Output

Hi-Z

Low

High

Low

Port Output Circuit

Nch-open drain

CMOS

VDDP1

Principles of Operation

The LC709004A accomplishes data transmission and reception to and from the MCU through synchronous serial

communication and performs I/O operations on the extended ports in parallel mode. Its communication modes (MCU to

LC709004A by serial to parallel conversion and LC709004A to MCU by parallel to serial conversion) include the

initial communication modes (modes 0 and 1) in which the LC709004A initializes itself and the data communication

mode in which the LC709004A sends and receives port data. The initial communication modes are used for various

communication control purposes for the first time in system operation after a power-on or system reset. In these modes,

the LC709004A sets up the I/O mode and output type of the ports. The data communication mode is used for

communication control after the end of the initial communication modes. In this mode, the LC709004A carries out

actual port I/O operations. The port I/O mode and output type settings are stored in the data direction register (DDR).

The data output state settings ("High" output, "Hi-Z" output, or "Low" output) are stored in the data register (DTR).

The LC709004A's operating modes are summarized below, followed by detailed mode descriptions.

Communication Mode

Initial communication mode

Mode 0

Mode 1

Data communication mode

Description

Sets the output type of all ports to "N-ch-open drain."

Sets the I/O direction of the ports and the their output type to CMOS or "Nch-open-drain" on a bit basis.

Sends and receives port data.

No.A0165-7/13

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