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User’s Manual U12697EJ3V0UM
CHAPTER 14 D/A CONVERTER
14.1 Function
The D/A converter converts the digital input into analog values and consists of two channels of voltage output D/
A converters with 8-bit resolution.
The conversion method is a R-2R resistor ladder.
Set DACE0 of D/A converter mode register 0 (DAM0) and DACE1 of D/A converter mode register 1 (DAM1) to
start the D/A conversion.
The D/A converter has the following two modes.
(1) Normal mode
After D/A conversion, the analog voltage is immediately output.
(2) Real-time output mode
After D/A conversion, the analog voltage is output synchronized to the output trigger.
Since a sine wave is created when this mode is used, MSK modems can be easily incorporated into cordless
phones.
Caution If only one channel of the D/A converter is used when AV
REF1
< V
DD
, make either of the
following setting at pins that are not used for analog output.
•
Set the port mode register (PM13X) to one (input mode) and connect to V
SS
.
•
Set the port mode register (PM13X) to zero (output mode) and the output latch to zero,
and output a low level.
14.2 Configuration
The D/A converter includes the following hardware.
Table 14-1. Configuration of D/A Converter
Item
Configuration
Registers
D/A conversion setting register 0 (DACS0)
D/A conversion setting register 1 (DACS1)
Control registers
D/A converter mode register 0 (DAM0)
D/A converter mode register 1 (DAM1)
