Datasheet

Rev.6.00 Oct.28.2004 page 559 of 1016
REJ09B0138-0600H
17.3 Operation
The D/A converter includes D/A conversion circuits for two channels, each of which can operate independently.
D/A conversion is performed continuously while enabled by DACR. If either DADR0 or DADR1 is written to, the new
data is immediately converted. The conversion result is output by setting the corresponding DAOE0 or DAOE1 bit to 1.
The operation example described in this section concerns D/A conversion on channel 0. Figure 17-2 shows the timing of
this operation.
[1] Write the conversion data to DADR0.
[2] Set the DAOE0 bit in DACR to 1. D/A conversion is started and the DA0 pin becomes an output pin. The conversion
result is output after the conversion time has elapsed. The output value is expressed by the following formula:
DADR contents
× V
ref
256
The conversion results are output continuously until DADR0 is written to again or the DAOE0 bit is cleared to 0.
[3] If DADR0 is written to again, the new data is immediately converted. The new conversion result is output after the
conversion time has elapsed.
[4] If the DAOE0 bit is cleared to 0, the DA0 pin becomes an input pin.
Conversion data 1
Conversion
result 1
High-impedance state
t
DCONV
DADR0
write cycle
DA0
DAOE0
DADR0
Address
ø
DACR
write cycle
Conversion data 2
Conversion
result 2
t
DCONV
Legend:
t
DCONV
: D/A conversion time
DADR0
write cycle
DACR
write cycle
Figure 17-2 Example of D/A Converter Operation