UPD784020 Datasheet, PDF (36/90 Pages) NEC – 16/8-BIT SINGLE-CHIP MICROCOMPUTER

mPD784020, 784021
8.7 D/A CONVERTER
Two digital/analog (D/A) converter channels of voltage output type, having a resolution of 8 bits, are incorporated.
A resistor string system is used for conversion. By writing the value to be subject to D/A conversion in the 8-bit
D/A conversion value setting register (DACSn: n = 0, 1), the resulting analog value is output on ANOn
(n = 0, 1). The range of the output voltages is determined by the voltages applied to the AVREF2 and AVREF3 pins.
Because of its high output impedance, no current can be obtained from an output pin. When the load impedance
is low, insert a buffer amplifier between the load and the converter.
The impedance of the ANOn pin goes high while the RESET signal is low. DACSn is set to 0 after a reset
is released.
Fig. 8-8 Block Diagram of D/A Converter
AVREF2
R
R
R
R
AVREF3
ANOn
RESET
DACSn
DACEn
8
8
Internal bus
Remark n = 0, 1
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