UPD784031 Datasheet, PDF (35/90 Pages) NEC – 16/8-BIT SINGLE-CHIP MICROCONTROLLER

µPD784031
8.7 D/A Converter
Two digital/analog (D/A) converter channels of voltage output type, having a resolution of 8 bits, are incorporated.
An R-2R resistor ladder 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.
Figure 8-8. Block Diagram of D/A Converter
AVREF2
2R
R
2R
ANOn
AVREF3
Selector
R
2R
R
2R
DACSn
DACEn
Internal bus
Remark n = 0, 1
35