CHAPTER 13 D/A CONVERTER
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User
’
s Manual U14701EJ3V0UD
13.4 D/A Converter Operation
13.4.1 Basic operations of D/A converter
<1>
Set the data that corresponds to the analog voltage that is output to AO0/P120 pin of D/A conversion value
setting register 0 (DA0).
Set bit 0 (DACE) of D/A converter mode register 0 (DAM0) to start D/A conversion.
After D/A conversion, the analog voltage is immediately output to AO0/P120 pin.
The output analog voltages are held until new data are set in DA0.
<2>
<3>
<4>
Caution Set DACE after data are set in DA0.
13.4.2 Operation during standby mode
D/A converter operation is retained during standby mode.
The values in D/A converter mode register 0 (DAM0) and D/A conversion value setting register 0 (DA0) are retained.
Caution Set bit 0 (DACE) of DAM0 to 0 and stop DA0 before entering standby mode in order to reduce
current consumption during standby mode.
13.4.3 Operation at reset
Reset input initializes DA0, stops D/A conversion operation, and put analog output to high-impedance state. In
addition, D/A converter mode register 0 (DAM0) and D/A conversion value setting register 0 (DA0) are cleared to 00H.
13.5 D/A Converter Cautions
(1) Output impedance of the D/A converter
Since the output impedance of the D/A converter is high, the current cannot be taken from the AO0 pin. If the
input impedance of the load is low, insert a buffer amp between the load and the AO0 pin. In addition, use the
shortest possible wire from the buffer amp or load (to increase the output impedance). If the wire is long, surround
it with a ground pattern.