Hookint; Charging - Nokia RH-6 Series Baseband Description & Troubleshooting

CCS Technical Documentation
RH-6 supports fully differential external audio signals. A headset can be connected to
the Pop-port system connector. However, only Mono audio is supplied to accessories.

HookInt

This signal is used to detect whether a button in accessory is pressed or not. The hook
signal is generated by creating a short circuit (20 ohm) between the headset microphone
signals (XMICP and XMICN). In this case, an LP-filter is needed on the HookInt input to
filter the audio signal.
If no accessory is present, the HookInt signal is pulled up by the UEM resistor.
If an accessory inserted and the microphone path is biased the HookInt signal decreases
to 1.9V due to the microphone bias current flowing through the resistor. When the but-
ton is pressed the microphone signals are connected together, and the HookInt input will
get half of micbias dc value 1.1V. This change in DC level will cause the HookInt compar-
ator output to change state, in this case from 0 to 1.
HookInt comparator reference is selected level is 1.35 V.
Normally micbias and hookint are enabled only when audios are routed to headset.
In order to recognize the Hook signal (button in headset or SyncButton in desk stand),
during the phone is in the sleep mode, it must be done by polling. That means the
micbias and the hookInt signal must be enabled in regular time intervals.
Signal Min
VFLASH1 2.7
MICB2 2.0
Vhook1 1.25

Charging

RH-6 can be charged via a DC-plug or charging pins on the system connector. Further-
more, it supports only 2-wire charging.
DC-Plug
Like most Nokia phones, RH-6 uses a 3.5mm DC-plug. Nevertheless, it is possible to use a
3-wire charger, but the PWM inside these chargers is not supported.
VCHAR pins of system connector
The VCHAR and ChargeGND pin are directly connected to the normal charger lines of the
Issue 1 10/2003
Company Confidential
Table 21: Voltage Levels Hook Int
Nom Max Unit
2.78 2.86 V
2.1 2.25 V
600 uA
1.35 1.45 V
© 2003 Nokia Corporation.
6 - BB Description & Troubleshooting
Note
RH-6
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