FEDL9090A-01
1
Semiconductor
ML9090A-01, -02
• RESET
Reset signal input pin. The initial state can be set by pulling this pin to an “L” level. Refer to the “Output, I/O and
Register States in Response to Reset Input” page for the initial states of each register and display.
An internal pull-up resistor is connected to this pin. An external capacitor is connected for power-on-reset
operation.
• TEST
Test signal input pin. This pin is used for testing by Oki. Connect this pin to VSS. When a different connection is
made, proper operation cannot be guaranteed.
• R0 to R4
Key switch scan signal output pins. During the scan operation, “L” level signals are output in the order of R0,
R1, ...R4. (Refer to the page entitled “Key scan” for details.)
• C0 to C4
Input pins that detect the key switch status. Internal pull-up resistors are connected to these pins. Assemble a key
matrix between these pins and the R0 to R4 pins.
• PA0
General-purpose port A output pin. Because this pin can output a current of –15 mA, it is best suited as an LED
driver. If this pin is used as an LED driver, insert an external current limiting resistor in series with the LED. If this
pin is not used, leave it unconnected (open).
• PB0 to PB7
General-purpose port B output pins. Each of the PB5 to PB7 pins has the same driving capability as the PA0 pin,
namely the ability to output a current of –15 mA. These pins are only applicable to the ML9090A-01. Leave
unused pins unconnected (open).
• SEG1 to SEG80
Segment signal output pins for LCD driving. Leave unused pins unconnected (open).
• COM1 to COM18
Common signal output pins for LCD driving. Leave unused pins unconnected (open). COM11 to COM18 are
provided for the ML9090A-02 and PB0 to PB7 for the ML9090A-01.
• VDD
Logic power supply connection pin.
• VSS
Power supply GND connection pin.
• DT
This pin selects the voltage multiplier circuit. If this pin is connected to the VSS pin, the voltage doubler circuit is
selected. If this pin is connected to the VDD pin, the voltage tripler circuit is selected. Do not change the value of the
setting after power is turned on.
• VC1, VC2
Capacitor connection pins for the voltage multiplier. Connect a 4.7 µF capacitor between the VC1 and VC2 pins. If
an electrolytic capacitor is used, connect the (+) side to pin VC2.
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OKI [ OKI ELECTRONIC COMPONETS ]
