Headset Type Detect - Cirrus Logic CS42L42 Manual

4.13 Headset Type Detect

The CS42L42 can detect whether headset Pins 3 and 4 are either the mic or ground signal and can set the appropriate
connections via internal switches, as shown in
Headset Interface
GNDA
Type Detect
HP Detect
S0 Detect
DC Detect
HSBIAS_FILT_REF_RS p. 132
SW_HSB_FILT_HSx p. 135
HSBIAS_FILT_REF
HSBIAS_FILT HS Bias
Generator
SW_HSB_HSx p. 135
Headset Type
Detection Logic
HSDET_CTRL p. 135
HSDET_SET p. 135
Control
Port
HSDET_COMPx_
OUT p. 136
External switches can improve system cross-talk performance by providing a lower impedance path to ground for HP and
mic currents. In this case, minimize the impedance from the connection to the headset connector to ground through the
external switches. This includes any switch, trace, and series filter impedance.
4.13.1 Headset-Type Detection
Operation of the headset-detect circuit is determined by the
• If HSDET_CTRL = 00 or 01, any internal switches can be set manually via the headset switch control bits (SW_x_
y, see Section 7.4.13).
DS1083F2
Fig. 4-43.
CS42L42
HPOUT_CLAMP from DAC
p. 154
from DAC
SW_REF_HSx
SW_GNDHS_
HSx p. 135
HS_DETECT
HS_DETECT_ REF
HSBIAS_REF p. 135
2.21 k, see Table 3-14
for specifications
HS_CLAMP_
DISABLE p. 136
+
–
HSDET_COMP1_LVL
p. 134
+
HSDET_
–
COMP2_LVL
SW_HSB_
p. 134
HSx p. 135
SW_GNDHS_HSx p. 135
Figure 4-43. Headset Type Detect—Overview
+VCP_FILT
HPSENSB
HPOUTB
–
+
RING_SENSE
–VCP_FILT
TIP_SENSE
+VCP_FILT
HPSENSA
HPOUTA
+
–
–VCP_FILT
HSIN–
p. 135
HSIN+
HP_REF_RS
p. 132
HS3_REF
HS4_REF
HS3
HS4
HS_ CLAMP1
HS_ CLAMP2
GNDHS
HSDET_CTRL setting (see
CS42L42
4.13 Headset Type Detect
Headset Connector
Isolation Filter
Isolation Filter
Isolation Filter
1 2
Isolation Filter
Isolation Filter
Isolation Filter
Isolation Filter
Isolation Filter
p. 135), described as follows:
3 4
78