HD6432621 Hitachi, HD6432621 Datasheet - Page 653

• Manufacturer Part Number: HD6432621
• Description: (HD64F262x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

17.3
The D/A converter has two built-in D/A conversion circuits that can perform conversion
independently.
D/A conversion is performed constantly while enabled in DACR23. If the DADR2 or DADR3
value is modified, conversion of the new data begins immediately. The conversion results are
output when bits DAOE0 and DAOE1 are set to 1.
An example of D/A conversion on channel 2 is given below. The timing is shown in figure 17-2.
1. Data to be converted is written in DADR2.
2. Bit DAOE0 is set to 1 in DACR23. D/A conversion starts and DA2 becomes an output pin.
3. If the DADR2 value is modified, conversion starts immediately, and the result is output after
4. When the DAOE0 bit is cleared to 0, DA2 becomes an input pin.
The conversion result is output after the conversion time. The output value is (DADR2
contents/256)
modified or the DAOE0 bit is cleared to 0.
the conversion time.
ø
Address
DADR2
DAOE0
DA2
Legend
t
DCONV
Operation
: D/A conversion time
High-impedance state
write cycle
DADR2
Vref. Output of this conversion result continues until the value in DADR2 is
Figure 17-2 Example of D/A Converter Operation
write cycle
DACR23
Conversion data 1
t
DCONV
Conversion
result 1
write cycle
DADR2
t
DCONV
Conversion data 2
Conversion
result 2
write cycle
DACR23
609