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FUJITSU MB91F109 FR30 User Manual

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CHAPTER 11 A/D CONVERTER (Successive approximation type)

11.1 Overview of A/D Converter (Successive Approximation

Type)

The A/D converter converts analog input voltage to digital values.

Characteristics of A/D Converter

Minimum conversion time: 5.6

µ

s/ch (for 25 MHz system clock)

Built-in sample & hold circuit

10- bit resolution

Program selection of analog input from four channels

Single conversion mode: One channel is selected and converted.

Scan conversion mode: Multiple consecutive channels are converted. Up to four
channels can be programmed.

Continuous conversion mode: The specified channel is converted repeatedly.

Convert-and-stop mode: When one channel is converted, the converter stops and waits
for the next activation (the beginning of conversion can be synchronized).

DMA transfer activated by an interrupt

Choices of software, external trigger (falling edge), and reload timer (rising edge) for
activation

A/D Converter Registers

Figure 11.1-1 shows the A/D converter registers.

Figure 11.1-1 A/D Converter Registers

15

0

ADCS

ADCR

16bit

bit

15

14

13

12

11

10

9

8

BUSY

INT

INTE PAUS STS1 STS0 STRT

(ADCS)

bit

7

6

5

4

3

2

1

0

MD1

MD0

ANS2 ANS1 ANS0 ANE2 ANE1 ANE0

bit

15

14

13

12

11

10

9

8

(ADCR)

bit

7

6

5

4

3

2

1

0

7

6

5

4

3

2

1

0

9

8

Control status register

Data register