HD64F2638F20J Datasheet, PDF (761/1512 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

H8S/2639, H8S/2638, H8S/2636,
H8S/2630, H8S/2635 Group
Section 18 D/A Converter
18.3 Operation
The D/A converter module has one on-chip D/A converter circuits that can operate independently.
D/A conversion is performed continuously whenever enabled by the D/A control register (DACR).
When a new value is written in DADR0 or DADR1, conversion of the new value begins
immediately. The converted result is output by setting the DAOE0 or DAOE1 bit to 1.
An example of conversion on channel 0 is given next. Figure 18-2 shows the timing.
• Software writes the data to be converted in DADR0.
• D/A conversion begins when the DAOE0 bit in DACR is set to 1. After the elapse of the
conversion time, analog output appears at the DA0 pin. Contents of DADR / 256 × Vref
This output continues until a new value is written in DADR0 or the DAOE0 bit is cleared to 0.
• If a new value is written in DADR0, conversion begins immediately. Output of the converted
result begins after the conversion time.
• When the DAOE0 bit is cleared to 0, DA0 becomes an input pin.
DADR0
write cycle
DACR
write cycle
DADR0
write cycle
DACR
write cycle
φ
Address
DADR0
Conversion data (1)
Conversion data (2)
DAOE0
DA0
High-impedance state
Conversion result (1)
t _DCONV
Conversion result (2)
t _DCONV
Legend:
t_DCONV: D/A conversion time
Figure 18-2 D/A Conversion (Example)
REJ09B0103-0800 Rev. 8.00
May 28, 2010
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