User's Manual

NEMO Bluetooth Radio Module
Solutions for a Real Time World Datasheet
Re-Tek - 1573 - 16 - 45388 Warm Springs Blvd. Fremont, CA
94539
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Copyright Unigen Corporation, 2008
FUNCTIONAL OVERVIEW
NEMO Hardware Functional Description
The NEMO is a complete Radio Transceiver Module operating in the license free ISM (Industrial
Scientific and Medical) 2.4GHz band. The Nemo module is equipped an external 26MHz crystal
oscillator and BALUN for a single ended RF input and output path. NEMO incorporates CSR
BlueCore 6 ROM WLCP chipset that is fully compliant to the Bluetooth 2.1 specification with
Enhanced Data Rate (EDR) radio for transfers up to 3Mbit throughput.
The Nemo module has uses CSR’s BlueCore 6 built in voltage regulator for powering the radio and
digital circuitry. The separate IO supply line give the option of running the digital interfaces such
as the high speed UART and PCM port at different signal voltages to match the external host
MCU’s digital interfaces. The built in CSR voltage regulators supplies the 1.8V supply to the radio
and digital MCU blocks of the CSR chip.
The module converts CSRs differential RF output and input into a single ended RF path for
transmit and receive. Matching circuitry is in line between the CSR device and the BALUN for
optimized transmit output and receive sensitivity.
The high speed UART interface, PCM port, GPIO along with WLAN co-existence interface lines are
all brought outside of the module. The UART interface communicates with an external host
running the upper Bluetooth stack and using the BlueCore Serial Protocol over the Bluetooth
defined Host Controller Interface (HCI) layer. The UART is used to send HCI commands and
events to and from the external host to the NEMO module.
Asynchronous and Synchronous data is sent between the module and external host via the UART
interface as well. Asynchronous data sent and received over an Asynchronous packet switched RF
link defined by the Bluetooth specification as “Asynchronous ConnectionLess” (ACL). Synchronous
data such as audio data uses “Synchronous Connection Oriented” (SCO) circuit switched RF links
defined by the Bluetooth specification. ACL data links can retransmit lost or corrupted data
continuously due to the packet switched connection. SCO data can provide fast reliable
continuous synchronous data over the circuit-switched RF link.
Synchronous audio data received or transmitted over the air via a Bluetooth SCO connection can
be immediately decoded over the air and passed directly through CSR’s digital PCM port for audio
applications. The module also support I2S digital formats through the same physical PCM port for
systems supporting I2S interfaces.
A slow clock 32.768kHz input is brought out for support for Deep Sleep and Standy By low power
modes in between radio transmissions. This is used to keep the CSR radio from drifting out of