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14. 8-Bit DA Converter (DAC)

14.1 Register Configuration

TMP86CS44UG

14.1.1 DA Converter Operation

1. Starting DA conversion operation

DA converter operation is activated by setting DACCR<DADRV0> to “1”. The digital value in

DACDR is converted into an analog value and is output from the DAO pin.

After resetting, DACCR and DACDR are cleared to “0”. The DA converter goes the power down.

(DAO analog level is 0 V.)

2. Logical expression for converted value

The relation between a digital value and analog output voltage in DACDR can be expressed in the fol-

lowing equation.

3. The relation between DA conversion result and Analog output voltage.

Figure 14-2 DA conversion result (8-bit digital) vs Analog output voltage

Note 1: Analog reference voltage

It needs that these reference voltage are supplied from a stable power supply.

Note 2: Analog output pin

The analog output pin (DAO) is dedicated to analog output to ensure the precision and characteristics of

DA conversion. While DA conversion is being performed, do not execute input/output instructions on the

adjacent port. Otherwise, the precision of DA conversion may be adversely affected. Also note that DAO is

susceptible to noise (especially power supply noise) in some cases.

Note 3: Anti-noise measure

as near to the IC as possible. It is recommended to use a tantalum capacitor (10

μF) and multilayer ceramic

capacitor (0.1

μF) in combination.

VOA

32 2

0

DAO0 2

1

DAO1 2

2

DAO2 2

3

DAO3 2

4

DAO4 2

5

DAO5 2

6

DAO6 2

7

DAO7

×

+

×

+

×

+

×

+

×

+

×

+

×

+

×

+

304

------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- DAREF

×

=

DAREF

AVSS

AVDD

304

32 + 254

DAREF

304

32 + 255

DAREF

304

32 + 253

DAREF

304

32 + 252

DAREF

304

32 + 3

DAREF

304

32 + 2

DAREF

304

32 + 1

DAREF

304

32 + 0

Analog

output

voltage

Ideal conversion characteristic