Document
CML Microcircuits
COMMUNICATION SEMICONDUCTORS
CMX7261 Voice Multi-transcoder
D/7261_FI-2.x/4 June 2016
7261FI-2.x – G.723.1 Full Duplex Codec DATASHEET
Advance Information
Features
Half-duplex operation
Full-duplex operation
Codec support: o G.723.1 codec (5.3kbps / 6.3kbps rates) with Annex A o PCM (linear, µ-law, A-law),
Transcoding support: o PCM to G.723.1 and reverse o PCM μ/A/linear to PCM μ/A/linear transcoder
No external DSP or codecs required: simply upload Function Image™ (FI)
Transcoder routing: o Choice of input sources – C-BUS transfer to host, external PCM device/codec, analogue audio input o Choice of output sources – C-BUS transfer to host, external PCM device/codec, analogue audio output
C-BUS host serial interface o SPI-like with register addressing o Read/Write 128-word FIFOs and data buffers to streamline transfers and relax host service latency
Auxiliary functions o Three GPIOs o Analogue input/output gain adjustment o Analogue input multiplexer o Analogue output multiplexer
Master/Slave PCM serial interface o For external audio CODEC
Low power 3.3V operation with powersave functions Small 64-pin VQFN or LQFP package
Applications
Half duplex digital radio systems Full duplex digital radio systems Personal area network voice links Privacy-type digital voice communications Wireless PBX VoIP applications Digital Software Defined Radio (SDR)
Analogue In
Analogue Out
External ADC / DAC
GPIOs
ADC
Digital Filters
FIFO
Transcoder
DAC
PCM TalkThrough /
PCM
Digital Filters
Configuration
Transcoder Function Image™
CMX7261
Voice Multi-transcoder
3.3V
Registers
C-BUS
Host µC
3.3V
2016 CML Microsystems Plc
CMX7261 Voice Multi-transcoder
CMX7261
1 Brief Description
The CMX7261 Multi-transcoder IC is a device supporting multiple speech codecs in a single chip. When loaded with FI-2.x the CMX7261 is capable of encoding analogue voice into PCM (linear, µ-law or A-law) or G.723.1 data formats at either 5.3kbps or 6.3kbps. It is capable of decoding PCM or G.723.1 (both rates) back to analogue voice. It can also transcode data between PCM formats and G.723.1.
Input and output signals may be passed through the C-BUS interface, the PCM port or the on-chip converters (ADC/DAC).
The device utilises CML’s proprietary FirmASIC component technology. On-chip sub-systems are configured by a Function Image™ data file that is uploaded during device initialisation and defines the device's function and feature set. The Function Image™ can be loaded automatically from a host µC over the C-BUS serial interface or from an external memory device. The device's functions and features can be enhanced by subsequent Function Image™ releases, facilitating in-the-field upgrades.
The CMX7261 operates from a 3.3V supply and includes selectable powersaving modes. It is available in a 64-VQFN (Q1) or a 64-LQFP (L9) package.
Note that text shown in pale grey indicates features that will be supported in future versions of the device. This Data Sheet is the first part of a two-part document.
2016 CML Microsystems Plc
Page 2
D/7261_FI-2.x/4
CMX7261 Voice Multi-transcoder
Section
CONTENTS
CMX7261
Page
1 Brief Description ...................................................................................................................................... 2
2 History ..................................................................................................................................................... 5
3 Block Diagrams ........................................................................................................................................ 6 3.1 Half Duplex Transcoder .................................................................................................................................. 6 3.2 Full Duplex Transcoder ................................................................................................................................... 6
4 Pin and Signal List .................................................................................................................................... 8 4.1 Signal Definitions.......................................................................................................................................... 11
5 PCB Layout Guidelines and Power Supply Decoupling............................................................................ 12
6 6.1 6.2 6.3 6.4 6.4.1 6.4.2 6.5 6.5.1 6.5.2 6.5.3 6.6
External Components............................................................................................................................. 13 Xtal Interface ................................................................................................................................................ 13 C-BUS Interface...................................................................................................