User Guide

CC Technical Documentation System Module

RM-11

System Connector (Tomahawk)

The 14-pin Tomahawk bottom connector consists of charging plug socket and Tomahawk

System Connector. The Tomahawk system connector includes signals for the following:

Figure 17: Tomahawk bottom connector (charger plug socket and Tomahawk system connector)

Accessory Control Interface (ACI)

The ACI is a point-to-point, bi-directional serial bus. It has three main features:

• The insertion and removal detection of an accessory device

• Acting as a data bus, intended mainly for control purposes

• The identification and authentication of accessory type which is connected

The accessories are detected by the HeadInt signal when the plug is inserted. Normally

when an accessory is not present, the pull-up resistor 100k pulls up the HeadInt signal to

VFLASH1. If the accessory is inserted, the external resistor (located to accessory) works

as a voltage divider and decreases the voltage level below the threshold of Vhead. The

comparator output is then changed to a high state, which causes an interrupt.

If the accessory is removed, the voltage level of HeadInt increases again to VFLASH1. This

voltage level is higher than the threshold of the comparator and so its output is changed

to low, which leads to an interrupt. These HeadInt interrupts are initiated by the acces-

sory detection or removal sequence.

Table 6: Tomahawk system connector signals

Function Notes

Charging Pads for 2-wire charging in cradles

Audio 4-wire fully differential stereo audio output

2-wire differential microphone input

FM radio antenna connection

Power supply for accessories 2.78V/70mA output to accessories

ACI (Accessory Control Interface) Accessory detection/removal and controlling

FBUS Standard FBUS

DKU-5 (similar to USB) (optional) Power in 5V in from DKU-5 cable

XMIC N

XMIC P

ACI

Charge GND

Fbus TX

Fbus RX

DATA GND

Shielding GND

HSEAR_L_P

HSEAR_L_N

Shielding GND

Charge

Vout

HSEAR_R_N

HSEAR_R_P