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3. D/A Converter
The D/A converter can be used for such applications as an electronic volume control that operates using
analog voltage control.
When using the D/A converter, set the DA ON bit to "1", set the SEL0 bit to "0", and set the SEL1 bit to
"1". This outputs, from the DA OUT pin, the D/A analog voltage corresponding to the AR0~AR5 data.
Because setting data to the DA REF data 2 port (φL22) simultaneously updates the D/A conversion data
AR0~AR5, always set the AR4 and AR5 bits (φL22) last. When using the D/A converter and the A/D
converter at the same time, control the SEL0 and SEL1 bits by software and operate by time sharing. As
the D/A output goes to high impedance when the A/D converter is operating, connect a voltage retention
capacitor to the output.
Use the following formula to calculate the D/A output.
D/A
output
voltage
Note 55: The D/A output has an internal buffer. If necessary, add an external buffer.
Note 56: As the D/A output range is 0 V~V
Note 57: For D/A conversion, the string resistors are the V
n
(where n is the AR0~AR5 data value [decimal] 63 > = n > = 1)
=
V
×
REF
64
D/A Converter Structure
− 1.0 V, be careful when V
DD
53
= V
.
REF
DD
voltage divided into 64 increments.
REF
TC9314F
2003-07-03
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