FEDL2240DIGEST-02

OKI Semiconductor

ML2240 Family

11/24

FUNCTIONAL DESCRIPTION

Micro-computer Interface

The micro-computer interface in the ML2240 has 2 types of interface circuits built in: Parallel interface and serial

interface. The interface setting can be changed with the SERIAL pin.

SERIAL pin = "H" level: Serial interface

SERIAL pin = "L" level: Parallel interface

Table below shows the SERIAL pin status in the serial and parallel interfaces.

SERIAL = “L”

SERIAL = “H”

Parallel interface

Serial interface

D7 (I/O)

DI (I)

Serial data input pin

D6 (I/O)

SCK (I)

Serial clock input pin

D5 (I/O)

DO (O)

Channel status serial output pin

D4 (I/O)

STASEL (I)

Channel status switching pin

NCRn output at “L” level

BUSYn output at “H” level

D3 (I/O)

STA3 (O)

Channel 4 status output pin

D2 (I/O)

STA2 (O)

Channel 3 status output pin

D1 (I/O)

STA1 (O)

Channel 2 status output pin

D0 (I/O)

Data input and output pins/

status output pin

STA0 (O)

Channel 1 status output pin

1. Parallel Interface

When selecting the parallel interface, the I/O pins

CS, WR, D7 to D0, and RD are used as input pins to input

various commands and data, and as output pins to read out the status of the commands and data input.

The micro-computer interface becomes effective when the

CS pin is set to “L” level.

When a command or data is input, the input data to D7 through D0 pins is captured inside the device on the

rising edge of the

WR pin.

To read the channels status, pins

CS and RD are made “L” level. By doing so, the status signals of each channel

are output to D7 through D0 pins.

Command and Data Input Timing

CS (I)

WR (I)

D7 to D0 (I/O)

Data Stable