STA321 datasheet(72/157 Pages) STMICROELECTRONICS

72 / 157 page

Headphone detection

STA321

72/157

Doc ID 15351 Rev 3

Headphone detection

The headphone detector circuit, shown in Figure 51, is made with two schmitt-trigger

comparators (with different thresholds) which sense the value of the HPDECT input voltage

and modifies the HP_DET1 or the HP_DET2 level as given in Table 30 and Table 31 below.

The comparators are enabled or disabled with bits E_HP1 and E_HP2 in register HPDET2

on page 138

The comparator output status is provided via bits 1 and 0 of register HPDET2 on page 138.

One of the comparator outputs is then selected with register bit HPDET1.HPD_SEL, and

that signal is passed through a digital debouncing filter and supplied to the FFX modulator.

The PWM outputs are then modified depending on the settings of register bits

HPDST.HP_DET_FILT and HPDET1.HPD_ACT_MODE.

Table 30.

Headphone 1 detector

E_HP1

(register HPDET2)

HP-jack status

HP_DET voltage

HP_DET1

Status register bit

HPDST.HP_DET_FILT

Unplugged

Low

Plugged

High

Table 31.

Headphone 2 detector

E_HP2

(register HPDET2)

HP-jack status

HP_DET voltage

HP_DET2

Status register bit

HPDST.HP_DET_FILT

Unplugged

Low

Plugged

High

STA321 数据表(PDF) 72 Page - STMicroelectronics

STA321 数据表(HTML) 72 Page - STMicroelectronics

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 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

数据表下载