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Revision 1.0 Page 7 of 25
Headset Reference Design v1.0
3 Hardware description
3.1 nRD24V1 Radio module
The radio module is a complete system for telephone quality wireless headset applications intended for
VoIP. It can be used in a headset, or in an audio module for connection to a PC audio outlet. There are 6
GPIOs for buttons or LEDs on the radio module.
The radio module is mounted on a 25 x 12 x 0.8 mm, 4-layer FR4 circuit board, with components on one
side.
Figure 5. nRD24V1 radio module
3.1.1 Audio Codec
The audio codec is a XE3005 from Semtech that receives a 4.096 MHz master clock from the micro con-
troller. The micro controller configures the codec through the SPI interface. The 8 ksps audio samples are
transferred on the I2S interface, where the micro controller is the bus master.
The microphone input has a 1.1 VDC bias for driving the microphone.
The loudspeaker outputs are a differential class D output and need some external filtering components.
1 RF crystal 4 Audio codec
2 nRF24L01 5 MCU crystal
3MCU
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