CC8520

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SWRS091A – MARCH 2010

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Copyright

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COEXISTENCE AND AUDIO COMPRESSION

The CC8520 implements a wide range of techniques to maximize coexistence performance when operating in

an environment with other 2.4 GHz wireless devices. The built-in protocol implements adaptive frequency

hopping. This helps improve coexistence with RF sources that do not move around in frequency, such as IEEE

802.11 (Wireless LAN) devices, as well as providing robust performance in a multipath RF environment. Audio

is buffered in the receiver, and any data which is not correctly received, is retransmitted utilizing the high raw

datarate (5Mbps). When link quality is poor (e.g. when moving out of range), audio is muted until a reliable link

is restored.

Forward Error Correction (FEC) is built into the CC8520 modulation scheme. Furthermore, packets are divided

into independent sections so that an error in one section does not mean the whole packet is lost.

The CC8520 supports uncompressed PCM16 audio, with no modifications made to the digital audio. High

quality audio compression can optionally be enabled and effectively reducing average current consumption by

lowering the radio duty-cycle. Compression improves robustness further, as there is less data sent and more

time available for retransmission.

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AUDIO INTERFACE

The CC8520 audio interface is I2S compatible and it supports up to 2 audio channels. The audio interface on

the protocol master can be configured as clock master (supplied from the internal audio PLL) or as clock slave

(clock supplied from external audio IC).

The audio interface has 2 data pins. Each of these can be configured as an input, output or unused. The audio

interface can be configured to support I2S. The CC8520 supports word widths of 16 to 24 bits, but over-the-air

16 bits is always used.

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HUMAN INTERACTION DRIVERS (HID)

The CC8520 supports basic HID functionality without an external MCU. This means that some basic

functionality can be controlled on the slave remotely from the master. The HID functionality supported

includes:

- power control (to turn devices on/off)

- network binding (to pair devices)

- volume control (volume control can be managed locally)

- Status LED (blinking diode to indicate the status of the RF link)

All HID functions are configurable in the PPW Configurator [1] and can be mapped to the CC8520 I/O pins.

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EXTERNAL HOST INTERFACE (EHIF / Data side channel)

The external host interface (EHIF) allows an external host device, e.g. a microcontroller, to:

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Control the operation of and poll status from the CC8520, mainly by taking over driver functionality.

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Communicate with other external host devices through an integrated data side-channel

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Get access to test functionality for audio, I/O and RF.

The external host interface is available via SPI with a single interrupt pin. The external host will act as SPI

master and CC8520 will act as SPI slave.

User specified data can be transferred between the master EHIF and the slave EHIFs, in both directions using

the data side-channel. The data side-channel establishes robust, ensured-delivery connections in both

directions from any slave to the master or from master to any slave (direct slave to slave communication is not