Renesas H8SX/1650, Hardware Manual

Page: 571 / 692

Section 15 D/A Converter
Rev.2.00 Jun. 28, 2007 Page 549 of 666
REJ09B0311-0200
15.4 Operation
The D/A converter includes D/A conversion circuits for two channels, each of which can operate
independently. When the DAOE bit in DACR01 is set to 1, D/A conversion is enabled and the
conversion result is output.
An operation example of D/A conversion on channel 0 is shown below. Figure 15.2 shows the
timing of this operation.
1. Write the conversion data to DADR0.
2. Set the DAOE0 bit in DACR01 to 1 to start D/A conversion. The conversion result is output
from the analog output pin DA0 after the conversion time t
DCONV
has elapsed. The conversion
result continues to be output until DADR0 is written to again or the DAOE0 bit is cleared to 0.
The output value is expressed by the following formula:
Contents of DADR/256
×
V
ref
3. If DADR0 is written to again, the conversion is immediately started. The conversion result is
output after the conversion time t
DCONV
has elapsed.
4. If the DAOE0 bit is cleared to 0, analog output is disabled.
Conversion data 1
Conversion
result 1
High-impedance state
t
DCONV
DADR0
write cycle
DA0
DAOE0
DADR0
Address
P
φ
DACR01
write cycle
Conversion data 2
Conversion
result 2
t
DCONV
[Legend]
t
DCONV
: D/A conversion time
DADR0
write cycle
DACR01
write cycle
Figure 15.2 Example of D/A Converter Operation