Fbus; Aci Interface - Nokia E62 Service Manual

RM-88
Nokia Customer Care System Module
Between EM (N2200) and cellular RF there are 8 pins + VBAT. RF is controlled directly by RAP and N2200. Digital
control signals, such as RFBus and reset signals, are taken from RAP and analog control signals, such as AFC
and TxC, are taken from EM ASIC (N2200).
RFBUS is similar control bus than CBUS and DBUS, but it is only used as controlling interface between RF and
BaseBand (RAP). RAP controls AFC and TxC signals via TxCData bus and RF regulator control is done via CBUS.
Analog Rx and Tx signals are connected to/from RAP that includes RF converters for this purpose. The TxC
serial bus interface is a one-way bus, which is used to transfer data from RAP3G to the N2200 ASIC TXC DACs.
These DACs are used to control the RF power amplifiers. The TXC bus includes TxCCtrl pin, which is used to
select the EM ASIC (N2200) DAC, the data is written to. In case the TxCCtrl is in low state, the data is written
to the DAC1 and in case the TxCCtrl is in high state, the data is written to DAC2.
The TxC bus clock frequency is programmable but the frequency to be used in CeBBo1 is 19.2 MHz and for
RFBUS the frequency used is 9.6 MHz.

FBUS

USB and FBUS have multiplexed interface between EM ASIC (2300) and RAP.

ACI interface

The ACI (Accessory Control Interface) is a point-to-point, bi-directional, single line serial bus.
It has two main features: the insertion and removal detection of an accessory device and acting as a data
bus between phone and accessory, intended for control purposes. A third function of ACI is to identify and
authenticate the accessory.
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