Rainbow-electronics ATmega64M1 Instrukcja Użytkownika Pobierz pdf (Strona 268)

268

8209A–AVR–08/09

ATmega16M1/32M1/64M1

• Bit 6:4 – DATS[2:0]: DAC Trigger Selection bits

These bits are only necessary in case the DAC works in auto trigger mode. It means if DAATE

bit is set.

In accordance with the Table 25-1, these 3 bits select the interrupt event which will generate the

update of the DAC input values. The update will be generated by the rising edge of the selected

interrupt flag whether the interrupt is enabled or not.

• Bit 2 – DALA: Digital to Analog Left Adjust

Set this bit to left adjust the DAC input data.

Clear it to right adjust the DAC input data.

The DALA bit affects the configuration of the DAC data registers. Changing this bit affects the

DAC output on the next DACH writing.

• Bit 1 – DAOE: Digital to Analog Output Enable bit

Set this bit to output the conversion result on D2A,

Clear it to use the DAC internally.

• Bit 0 – DAEN: Digital to Analog Enable bit

Set this bit to enable the DAC,

Clear it to disable the DAC.

25.5.2 DACH and DACL – Digital to Analog Converter input Register

DACH and DACL registers contain the value to be converted into analog voltage.

Writing the DACL register prohibits the update of the input value until DACH has not been writ-

ten too. So the normal way to write a 10-bit value in the DAC register is firstly to write DACL the

DACH.

In order to work easily with only 8 bits, there is the possibility to left adjust the input value. Like

this it is sufficient to write DACH to update the DAC value.

Table 25-1. DAC Auto Trigger source selection

DATS[2:0] Description

000 Analog comparator 0

001 Analog comparator 1

010 External Interrupt Request 0

011 Timer/Counter0 Compare Match

100 Timer/Counter0 Overflow

101 Timer/Counter1 Compare Match B

110 Timer/Counter1 Overflow

111 Timer/Counter1 Capture Event

1 2 ... 263 264 265 266 267 268 269 270 271 272 273 ... 342 343

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Rainbow-electronics ATmega64M1 Instrukcja Użytkownika Strona 268