HD64F2357F20V Datasheet, PDF (589/1049 Pages) Renesas Technology Corp – Hardware Manual Renesas 16-Bit Single-chip Microcomputer H8S Family / H8S/2300 Series

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
256
× V_ref
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.
DADR0
write cycle
DACR
write cycle
DADR0
write cycle
DACR
write cycle
ø
Address
DADR0
DAOE0
Conversion data 1
Conversion data 2
DA0
High-impedance state
t_DCONV
Conversion
result 1
Conversion
result 2
t_DCONV
Legend:
t_DCONV: D/A conversion time
Figure 17-2 Example of D/A Converter Operation
Rev.6.00 Oct.28.2004 page 559 of 1016
REJ09B0138-0600H