Philips Semiconductors

Preliminary specification

XA-S3

XA 16-bit microcontroller

32 K/1 K OTP/ROM/ROMless, 8-channel 8-bit A/D, low voltage (2.7 V–5.5 V),

2000 Dec 01

15

ADCS0

LSB

MSB

BIT

SYMBOL

FUNCTION

ADCS.7

ADCS7

A/D channel 7 select bit.

ADCS.6

ADCS6

A/D channel 6 select bit.

ADCS.5

ADCS5

A/D channel 5 select bit.

ADCS.4

ADCS4

A/D channel 4 select bit.

ADCS.3

ADCS3

A/D channel 3 select bit.

ADCS.2

ADCS2

A/D channel 2 select bit.

ADCS.1

ADCS1

A/D channel 1 select bit.

ADCS.0

ADCS0

A/D channel 0 select bit.

ADCS1

ADCS2

ADCS3

ADCS4

ADCS5

ADCS6

ADCS7

ADCS

Address:43Fh

Bit Addressable

Reset Value: 00h

SU00939

Figure 2. A/D Channel Select Register (ADCS)

LSB

MSB

BIT

SYMBOL

FUNCTION

ADCFG.7

—

Reserved for future use. Should not be set to 1 by user programs.

ADCFG.6

—

Reserved for future use. Should not be set to 1 by user programs.

ADCFG.5

—

Reserved for future use. Should not be set to 1 by user programs.

ADCFG.4

—

Reserved for future use. Should not be set to 1 by user programs.

ADCFG.3–0

ADCFG

A/D timing configuration (see text and table).

A/D Timing Configuration

—

—

—

—

ADCFG

Address:4B9h

Not bit Addressable

Reset Value: 00h

SU00940

Figure 3. A/D Timing Configuration Register (ADCFG)

Table 2. A/D Timing Configuration

ADCFG 3 0

Max. Oscillator

Conversion Time

Sampling Time

ADCFG.3–0

Frequency (MHz)

Osc. Clocks

µsec at max. Osc.

pg

(Osc. Clocks)

0h (0000)

6.66

72

10.81

4

1h (0001)

10

76

7.6

6

2h (0010)

11.11

80

7.2

8

3h (0011)

13.33

96

7.2

8

4h (0100)

16.66

100

6.0

10

5h (0101)

20

104

5.2

12

20

116

5.8

24

7h (0111)

22.2

108

4.86

14

8h (1000)

23.3

124

5.32

14

9h (1001)

26.6

128

4.81

16

Ah (1010)

30

132

4.4

18

30

146

4.87

32

Ch (1100)

–

136

4.25

20

Dh (1101)

–

152

4.56

20

Eh (1110)

–

172

4.7

22

Fh (1111)

–

176

4.4

24

NOTE:

1. These settings provide additional A/D input sampling time, in order to allow accurate readings with a higher external source impedance.