FEDL2240DIGEST-02
OKI Semiconductor
ML2240 Family
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)
D6 (I/O)
D5 (I/O)
D4 (I/O)
DI (I)
Serial data input pin
SCK (I)
DO (O)
Serial clock input pin
Channel status serial output pin
Channel status switching pin
NCRn output at “L” level
BUSYn output at “H” level
Channel 4 status output pin
Channel 3 status output pin
Channel 2 status output pin
Channel 1 status output pin
Data input and output pins/
status output pin
STASEL (I)
D3 (I/O)
D2 (I/O)
D1 (I/O)
D0 (I/O)
STA3 (O)
STA2 (O)
STA1 (O)
STA0 (O)
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)
Data Stable
D7 to D0 (I/O)
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