Fig 12 Headset Interface - Nokia RH-9 Series Ccs Technical Documentation

RH-9
System Module & UI
1 Micbias is set to high impedance state
HeadInt interrupt is detected
2
EAD reading below 0.35V
3
Micbias is set active 2.1V
4
EAD reading 1.0V - 2.2V -> Headset connected
5
Name Function
Headint Accessory detection
Ead / hookint Micbias=High-Z
Micbias active 2.1V
The hook signal is generated by creating a short circuit between the headset microphone
signals. When no accessory is present the HookInt signal is pulled up by the UEM. When
the accessory is inserted and the microphone path is biased the HookInt signal decreases
to 1.8V due to the microphone bias current flowing through the upper bias resistor net-
work. When the button is pressed the microphone signals are connected together and
the HookInt will fall below trigger treshold level 1.35V. This change in DC level will cause
the HookInt comparator output to change state.
HeadInt comparator reference level is 1.90 V +-0.15 V. HookInt comparator reference is
selected by SW. Used trigger level is 1.35 V +/- 10mV.
PPH-1 Detection
PPH-1 accessory uses 4-wire fully differential audio connection. The accessory is
detected by the Headint signal when the plug is inserted. PPH-1 has two operating
modes with internal and external microphone. These modes can be separated by reading
the EAD value. Detection of the PPH-1 can be split in four main phases:
1 Micbias is set to high impedance state
HeadInt interrupt is detected
2
EAD reading is 2.0V - 2.7V -> PPH-1 connected
3
Name
Headint
Ead / hookint
The PPH-1 has a function of speaker mute. It can be muted by setting micbias in low
Page 40
Table 29: Headset identification
Min
2.2
1.009
1.596
Table 30: PPH-1 identification
Function Min
Accessory detection 2.2
Micbias = High-Z 2.064
2.487
1.840
ãNokia Corporation
CCS Technical Documentation
Typ Max Uni Description
t
2.78 2.86 V Accessory connected
0.35 V Headset
1.07 1.163 V Headset button closed
1.85 2.140 V Headset button open
Typ Max Unit
2.78 2.86 V
2.182 2.302 V
2.603 2.720 V
V
Description
Accessory connected
PPH-1 External Mic
PPH-1 Internal Mic
PPH-1 Speaker Mute
Issue 1 11/02