AD7142 datasheet(21/70 Pages) AD

21 / 70 page

Data Sheet

AD7142

Rev. B | Page 21 of 70

FF_SKIP_CNT

The proximity detection fast FIFO is used by the on-chip logic

to determine if proximity is detected. The fast FIFO expects to

receive samples from the converter at a set rate. FF_SKIP_CNT

is used to normalize the frequency of the samples going into the

FIFO, regardless of how many conversion stages are in a

sequence. In Register 0x02, Bits[3:0] are the fast filter skip

control, FF_SKIP_CNT. This value determines which CDC

samples are not used (skipped) in the proximity detection fast

FIFO.

Determining the FF_SKIP_CNT value is required only once

during the initial setup of the capacitance sensor interface.

Table 13 shows how FF_SKIP_CNT controls the update rate to

the fast FIFO. Recommended value for this setting when using

all 12 conversion stages on the AD7142 is FF_SKIP_CNT =

0000 = no samples skipped.

Table 13. FF_SKIP_CNT Settings

FAST FIFO Update Rate

FF_SKIP_CNT

DECIMATION = 128

DECIMATION = 256

1.536 × (SEQUENCE_STAGE_NUM + 1) ms

3.072 × (SEQUENCE_STAGE_NUM + 1) ms

6.144 × (SEQUENCE_STAGE_NUM + 1) ms

4.608 × (SEQUENCE_STAGE_NUM + 1) ms

9.216 × (SEQUENCE_STAGE_NUM + 1) ms

6.144 × (SEQUENCE_STAGE_NUM + 1) ms

12.288 × (SEQUENCE_STAGE_NUM + 1) ms

7.68 × (SEQUENCE_STAGE_NUM + 1) ms

15.36 × (SEQUENCE_STAGE_NUM + 1) ms

9.216 × (SEQUENCE_STAGE_NUM + 1) ms

18.432 × (SEQUENCE_STAGE_NUM + 1) ms

10.752 × (SEQUENCE_STAGE_NUM + 1) ms

21.504 × (SEQUENCE_STAGE_NUM + 1) ms

12.288 × (SEQUENCE_STAGE_NUM + 1) ms

24.576 × (SEQUENCE_STAGE_NUM + 1) ms

13.824 × (SEQUENCE_STAGE_NUM + 1) ms

27.648 × (SEQUENCE_STAGE_NUM + 1) ms

15.36 × (SEQUENCE_STAGE_NUM + 1) ms

30.72 × (SEQUENCE_STAGE_NUM + 1) ms

16.896 × (SEQUENCE_STAGE_NUM + 1) ms

33.792 × (SEQUENCE_STAGE_NUM + 1) ms

18.432 × (SEQUENCE_STAGE_NUM + 1) ms

36.864 × (SEQUENCE_STAGE_NUM + 1) ms

19.968 × (SEQUENCE_STAGE_NUM + 1) ms

39.936 × (SEQUENCE_STAGE_NUM + 1) ms

21.504 × (SEQUENCE_STAGE_NUM + 1) ms

43.008 × (SEQUENCE_STAGE_NUM + 1) ms

23.04 × (SEQUENCE_STAGE_NUM + 1) ms

46.08 × (SEQUENCE_STAGE_NUM + 1) ms

24.576 × (SEQUENCE_STAGE_NUM + 1) ms

49.152 × (SEQUENCE_STAGE_NUM + 1) ms

AD7142 датащи(PDF) 21 Page - Analog Devices

AD7142 датащи(HTML) 21 Page - Analog Devices

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70

датащи скачать

ссылки URL