MSC1215-XX OKI [OKI electronic componets], MSC1215-XX Datasheet - Page 16

• Manufacturer Part Number: MSC1215-XX
• Description: 17 x 2 Duplex Driver with Dimming, Keyscan and A/D Converter Function
• Manufacturer: OKI [OKI electronic componets]

¡ Semiconductor
Keyscan
To keep a scanning noise to a minimum, a scanning of the key switch starts only when a key is
pushed down or released. The scanning stops when CS input turns to "L" from "H" after sending
CS pulses two times and display data.
A/D Conversion
The IC has a built-in 6-ch ¥ 6-bit A/D converter.
As shown in the circuit below, the V
voltage divider and the divided analog voltage is used to input into the CH1 to CH6 pins.
PWM Dimming
Lamp PWM signal is input to the VD pin and converted to VF display PWM signal by the PWM
conversion circuit.
The conversion table is mark-programmable.
Note: The duty cycle of the lamp PWM signal is measured with a reference point of the
threshold voltage of the VD input pin. The threshold voltage changes due to process
parameter deviation. Therefore, the PWM conversion error increases as the rise/fall time
of the lamp PWM increases.
[Key Matrix of COL Input and ROW Output]
ROW1
S11
S12
S13
S14
Variable
Resistor
REF
[Circuit Example]
output pin is connected to a variable resistor forming a
ROW2
=
S21
S22
S23
S24
ROW3
S31
S32
S33
S34
CH1
V
REF
COL1
COL2
COL3
COL4
MSC1215-xx
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