CMLMICRO DE6491

CML Microcircuits
COMMUNICATION SEMICONDUCTORS
DE6491
CMX649 Wireless Voice Link
Demonstration Kit
User Manual
UM6491/1 April 2004
Advance Information
Features
•
Full-Duplex Wireless Voice-Link
Communication Demonstration
using the CMX649 ADM Voice
Codec
•
Privacy via CMX649 Digital Scrambler
•
On/Off, Volume and RF Channel Pushbutton
Controls
•
Operates in the 863 – 865 MHz
European Licence Free Band
•
Phone Quality Voice Transmission using Time
Division Duplex (TDD) Airlink Protocol
•
20m Range - Line of Sight
•
Selectable RF Power
1.
Brief Description
The DE6491 is a CMX649-based wireless voice link demonstration kit that demonstrates CMX649 ADM
Codec IC operation in a low-power, cordless headset application. Operating as a short range RF device
in the 863 – 865 MHz European licence-exempt band, this demonstration kit consists of two separate
stand-alone PCBs each with the following sections: CMX649-based audio, RF transceiver and control.
The basic design may be user adapted to other RF frequencies. Full-duplex voice operation at up to 20
metres range is provided via a single RF channel Time Division Duplex (TDD) link. With the supplied
headsets a user can investigate two-way voice-audio transfer between units.
Each PCB can be powered, standalone, from a choice of AAA batteries or a bench power supply.
Intelligent power saving reduces supply current when not communicating. Each terminal draws between
17 – 25.5 mA when communicating or 850µA, typical, when powersaved.
Each on-board µController's FLASH memory comes programmed with the latest version of operating
firmware. If desired, a user may reprogram and in-circuit debug the µController themselves, using a
proprietary programmer (not included).
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DE6491
CONTENTS
Page
Section
1
Brief Description ................................................................................. 1
2.
Preliminary Information ...................................................................... 4
2.1
Laboratory Equipment............................................................ 4
2.2
Handling Precautions ............................................................. 4
2.3
Approvals ................................................................................ 4
3.
Quick Start ........................................................................................... 5
3.1
Setting-Up ............................................................................... 5
3.2
Operation................................................................................. 5
4.
Signal Lists.......................................................................................... 8
5.
Circuit Schematics and Board Layout ............................................. 10
6.
Detailed Description.......................................................................... 11
6.1
Hardware Description ........................................................... 11
6.2
Firmware Description ........................................................... 12
6.3
Troubleshooting ................................................................... 15
7.
Performance Specification................................................................ 16
7.1
Electrical Performance ......................................................... 16
It is always recommended that you check for the latest product datasheet version from the Datasheets
page of the CML website: [www.cmlmicro.com].
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DE6491
Figure 1 Interactive Block Diagram
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2.
Preliminary Information
2.1
Laboratory Equipment
DE6491
The following laboratory equipment is needed to use each evaluation board:
•
2.2
Two Alkaline AAA batteries or a 2.9 – 5.5 V power supply.
Handling Precautions
Like most evaluation kits, this product is designed for use in laboratory environments. The
following practices will help ensure its proper operation:
2.2.1
Static Protection
This product uses low power CMOS circuits which can be damaged by electrostatic discharge.
Partially damaged circuits can function erroneously, leading to misleading results. Observe ESD
precautions at all times when handling this product.
2.2.2
Contents - Unpacking
Please ensure that you have received all of the items on the separate information sheet
(EK6491) and notify CML within 7 working days if the delivery is incomplete.
2.3
Approvals
Each board contains a low-power radio frequency transceiver operating with FSK modulation in
the 863 – 865 MHz band and is not approved by any regulatory agency or body. The boards are
intended for experimental use only and the user is responsible for ensuring that the operation of
these boards is both appropriate and lawful.
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3.
DE6491
Quick Start
This section provides instructions for users who wish to experiment immediately with the
demonstration kit. A fuller description of the kit and its use appears later in this document.
3.1
Setting-Up
Communication between the Master and Slave boards (see silk screen label for board type
identification) can be established after the following steps are performed:
1. Connect the provided headsets to the sockets J3 and J3a on each board, ensuring the
correct polarity of J3a.
2. Select the power supply for each board, either:
•
•
Install 2 Alkaline AAA batteries (not supplied) in J1 and connect JP1 pin 1 to pin 2.
Connect a 2.9 – 5.5 V power supply to J2 and connect JP1 pin 2 to pin 3.
3. Pair the boards - With the boards within RF range of each other (see section 3.2.5),
perform the pairing sequence described in section 3.2.1.
The boards will now be operational and the pairing process will not need to be performed again
as the pairing information is retained in the microcontroller's non-volatile memory.
3.2
Operation
Once a Master and Slave board (see silk screen label for board type identification) have been
paired, they will be operational and audio communication can be achieved between them. Audio
input to the Master board from the microphone will be heard in the Slave board’s earpiece and
audio from the Slave board’s microphone will be heard in the Master board’s earpiece.
The four buttons provided on each board allow the user to turn the power on/off, reset the boards,
control the volume, control RF channel selection and the pairing of two boards, as described
below.
3.2.1
Pairing Boards
Before the Master board and Slave board can communicate with one another, they must first be
“paired”. To perform the pairing process:
1.
2.
3.
4.
5.
Power the master and slave boards and place in close proximity
Press and release the reset button (RST) on each board.
Press and hold down the VOL- and VOL+ buttons on either the Slave or Master board.
After 3 - 4 flashes of the LED, the LED will remain constantly on.
While still holding the first pair of buttons, press and hold down the VOL- and VOL+
buttons on the other board.
6. After 3 - 4 flashes of the LED on the second board, the LED on the first board will go
out. This indicates the new pairing ID codes have been successfully exchanged, the
buttons on both boards can now be released.
7. The new pairing ID codes will be saved into non-volatile memory the next time the
boards enter powersave mode.
Once the two boards have been paired audio communication will be possible between them. The
pairing process will only need to be performed once. Only if one of the paired boards is to be
used with a different board should pairing need to be performed again.
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3.2.2
DE6491
Power Functions
The LED (D1) present on each board indicates the power state of the board as:
•
•
•
•
When the board leaves powersave mode and is powered up, the LED will stay on for
approximately 0.5s.
The LED will flash periodically, once every second, when a board is powered.
The LED will flash twice in quick succession when the board is entering powersave
mode.
When in powersave mode the LED will be inactive.
Both automatic and manual powersave functions are provided.
3.2.2.1 Automatic Power Functions
The automatic power functions allow the boards to power up and powersave when appropriate
without any user interaction. If voice is absent on both boards for a period greater than
approximately 30 seconds, the boards will enter powersave mode. The Master board and the
Slave board, if paired, will wake from powersave mode if voice is present at the audio input to
the Master board, i.e. from its microphone.
Also, the Slave board will automatically powersave if an RF connection to a paired Master board
is lost for an extended period (approximately 300ms), i.e. if the Slave board is moved out of
range or the Master board ceases communicating abruptly. Once an RF connection can again be
established with an active paired Master board, the Slave board will wake from powersave mode.
3.2.2.2 Manual Power Functions
Both boards provide controls to manually power up or powersave. By simultaneously pressing
both the VOL- button and VOL+ button on a board, the power state of the board will be toggled.
If a Master board is manually powersaved or powered up, a paired Slave board will also be
powersaved or powered up, if it is in range. Manually changing the power state of the Slave
board will not effect a paired Master board.
NB – Due to the automatic power functions, described in section 3.2.2.1, a board manually
powersaved or powered up may not remain power saved or powered up.
3.2.3
Adjusting Volume Levels
Two buttons are provided for earpiece volume controls, VOL+ and VOL-, which increase or
decrease the volume, respectively. Simply press and release either the VOL+ button or the VOLbutton to adjust the volume. Holding the button down will not ramp the volume. There are 32
volume increments available using the DE6491 board’s volume control buttons.
The volume level selected is retained when the boards are powersaved. The selected volume
level will only be lost if the power supply is removed or if the board is reset.
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3.2.4
DE6491
RF Channel Selection
The Channel button (CHNL) on each board allows the RF channel used for communication to be
changed; which may be required if RF interference is disrupting communications. To change the
RF channel simply press and release the channel button (CHNL) on one of the boards. Both
boards will then attempt to communicate on a different RF channel.
If the interference is too great and the RF channel cannot be changed successfully,
communication may be lost. To force both boards to use the same default RF channel again,
both boards must be reset, as described in section 3.2.6.
3.2.5
RF Power Selection
Four settings are available to allow the RF power output of each board to be adjusted. The
setting is selected by inserting or removing shorting links between pins 5 and 6 and pins 7 and 8
on header J4.
RF_POW0 and
RF_POW1
(J4 pins 5 and 6)
RF_POW2 and
RF_POW3
(J4 pins 7 and 8)
Link
Link
Open
Link
Open
Link
Open
Open
RF Power
setting
Maximum
(default)
High
Low
Minimum
Approx.
RF Power
(dBm)
Typical
Current
Draw (mA)
Maximum RF
range*
(metres)
+5.0
25.5
20.0
-2.0
-8.0
-19.0
20
18
17
12.0
8.0
3.0
*These range figures are for when the embedded PCB antenna is used and both paired boards
use the same RF power setting. The achievable RF range may vary depending on the
environmental conditions, including a building’s structure and any obstacles between the boards.
3.2.6
Reset Function
To reset a board press and release the RST button. Resetting a board will set both the volume
level and RF channel to their default values.
Communication may be lost between two paired boards if only one is reset. To recover
communications simply reset the other board to ensure both boards are communicating using the
default RF channel.
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4.
DE6491
Signal Lists
CONNECTOR PINOUT
Connector
Ref.
Connector
Pin No.
Signal
Name
Signal
Type
J2
1
VSS
Power
External Power Supply Connection
2
VIN
Power
External Power Supply Connection
B
VSS
Power
VSS Connection
C
SPKR-OUT
O/P
D
-
-
1
MIC-IN1
I/P
Analogue Voice Input from Headset
Microphone
2
MIC-IN2
I/P
Analogue Voice Input from Headset
Microphone
1
SPARE1
BI
Spare MSP430 I/O
2
SPARE2
BI
Spare MSP430 I/O
3
SPARE3
BI
Spare MSP430 I/O
4
SPARE4
BI
Spare MSP430 I/O
5
RF_POW0
O/P
RF Transmit Power Selection Pin
6
RF_POW1
I/P
RF Transmit Power Selection Pin
7
RF_POW2
O/P
RF Transmit Power Selection Pin
8
RF_POW3
I/P
RF Transmit Power Selection Pin
J3
J3a
J4
Description
Analogue Voice Output to Headset
Earpiece
No Connection
(See section 3.2.5 for details)
J5
9
VDD
Power
VDD Connection
10
VSS
Power
VSS Connection
1
TDO
O/P
2
-
-
3
TDI
I/P
4
VDD
Power
5
TMS
I/P
6
-
-
7
TCK
I/P
8
-
-
No Connection
9
VSS
Power
VSS Connection
10
-
-
No Connection
11
RST
I/P
12,13,14
-
-
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MSP430 JTAG Output
No Connection
MSP430 JTAG Input
MSP430 JTAG Reference Voltage Output
MSP430 JTAG Input
No Connection
MSP430 JTAG Input
MSP430 JTAG Input
No Connection
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DE6491
CONNECTOR PINOUT
Connector
Ref.
Connector
Pin No.
Signal
Name
Signal
Type
J6
N/A
ANT_EXT
Antenna
Description
External Antenna Connection
(See section 6.1.3 for details)
TEST POINTS
Test Point
Ref.
Default
Measurement
TP1
2.9V-5.5V
TP2
0V
VSS
TP3
N/A
TEST0
TP4
N/A
TEST1
TP5
N/A
TEST2
TP6
2.7V
2.7V_RF – CC1000 Power Supply
TP7
N/A
CC1000 DIO Signal
TP8
N/A
CC1000 DCLK Signal
TP9
0V
VSS
Description
Unregulated VDD
JUMPERS
Link
Ref.
JP1
Positions
1 - 2: J1 - AAA Battery
Holder
Default
Position
Description
1-2
Power Supply Source – Selects which power
supply to use
2 - 3: J2 - External
Power Supply
Notes: I/P =
O/P =
BI
=
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Output
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5.
DE6491
Circuit Schematics and Board Layout
For clarity, circuit schematics are available as separate high resolution files.
Figure 2 Demonstration Board Layout
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6.
Detailed Description
6.1
Hardware Description
DE6491
Both boards consist of three main ICs: the CML Microcircuits CMX649, as the voice codec, the
Chipcon CC1000, for the RF communication, and the Texas Instruments MSP430F147
microcontroller to control and transfer the data between the other two ICs and support the user
interface and airlink protocol.
6.1.1
Voice Codec Circuitry
The voice codec circuitry consists of the CMX649 and external passive components
recommended by the CMX649 datasheet. The microphone amplifier has low and high –3dB
frequency roll-off points of approximately 150Hz and 15kHz, respectively. To reduce the codec
circuitry’s footprint and cost, the CMX649 clock signal is provided by the MSP430F147 and not
by a crystal oscillator.
A Maxim MAX4368 audio amplifier is used to drive the earpiece with the Audio Out signal from
the CMX649. Its external components are designed for a highpass roll-off frequency of
approximately 150Hz when used with the 32Ω impedance headset speaker.
6.1.2
RF Transceiver Circuitry
The RF transceiver circuitry is based on the Chipcon CC1000PP reference design and the
passive components have been chosen to provide operation in the European wireless audio band
of 863 – 865 MHz, as stated in the CEPT ERC recommendation 70-03 Annex 13. Changes in
passive component values, firmware adjustments and the use of an external antenna would allow
a different RF band to be used for communication, see Chipcon documentation for details.
6.1.3
RF Antenna
Two options are provided for the RF antenna: an embedded antenna printed on each PCB
(default) and an external antenna which can be connected via the SMA connector J6. The
embedded antenna is selected when R6 is a shorting link and R7 is not fitted, the external
antenna is selected when R6 is not fitted and R7 is a shorting link.
6.1.4
Headsets
Connectors J3 and J3a allow the supplied headsets, each consisting of a microphone and
earpiece, to be attached to the boards.
6.1.5
Expansion
Connector J4 is provided for user expansion. Four unused I/O lines of the MSP430F147 and
VDD and VSS are available at this header.
6.1.6
In-Circuit Programming
Connector J5 provides connections to the MSP430F147 microcontroller’s JTAG interface to allow
the device to be reprogrammed and debugged using the proprietary programmer, Texas
Instruments MSP430 Flash Emulation Tool MSP-FETP430IF (not provided). The following
instructions are a guide to program and debug the MSP430F147 firmware:
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1. Connect the MSP-FET430IF to J5
2. Connect a power supply or battery
3. Start the programming or debug sequence in accordance with the programming tool
manufacturer’s specifications.
6.2
Firmware Description
A Texas Instruments MSP430F147IPM microcontroller is fitted to each of the DE6491 boards
and has been programmed by CML, before shipment, with the latest version of firmware. Please
read the separate information sheet (EK6491) and check the CML website for firmware status.
The latest source code and programming files (EF6491xxM.d43 and EF6491xxS.d43, for the
Master firmware and Slave firmware, respectively, ‘xx’ represents the version number) can be
downloaded from the CML website.
There are two types of firmware included with the DE6491 demonstration kit, one for the Master
board and one for the Slave board (see silk screen label for board type identification), both have
the same basic structure, as shown in Figure 3. The firmware controls the CML Microcircuits
CMX649 Voice Code, the Chipcon CC1000 RF transceiver and handles the transfer of data
between them. All communication is synchronised by the Master board.
6.2.1
The MSP430F147’s Interaction with the CMX649
On both the Master board and the Slave board, the CMX649 and its data are handled in the same
way. The CMX649 is set to use 31.25kbps ADM to encode and decode the audio, which is
created by dividing down a 4MHz clock signal provided by the MSP430F147. The CMX649 is
sent control commands from the MSP430F147 via the CBUS serial interface, see the CMX649
datasheet for details on the CBUS. The MSP430F147 buffers data received from the CMX649
into packets, each one containing approximately 30ms of audio, to be exchanged over the RF
link.
The Master board’s firmware also takes advantage of the CMX649’s programmable voice activity
detector (VAD) to determine when voice/audio is present. This allows the Master board to decide
when to powersave, i.e. after periods where voice/audio is consistently absent, and to wake from
powersave, i.e. when voice/audio has been detected.
6.2.2
The MSP430F147’s Interaction with the CC1000
The CC1000 and its data are handled by the MSP430F147 in an almost identical manner on both
the Master board and the Slave board. Control signals are sent to the CC1000 by the
MSP430F147 via the CC1000’s 3-wire serial interface. Data is transferred over the RF link by
the CC1000 at 76.8kbps and, therefore, data is transferred between the CC1000 and the
MSP430F147 at the same rate. The audio packets collected from the CMX649 are converted
into RF frames by the MSP430F147 and transmitted over the RF link by the CC1000.
Data is transferred over the RF link as half-duplex but provides the user with full-duplex audio
communication because the CC1000’s data rate is over twice the CMX649’s data rate; i.e. two
RF frames can be exchanged serially over the RF link, one in each direction, within the time it
takes the CMX649 to encode one audio packet and decode another audio packet in parallel.
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Reset or power supply
reconnected
Periodic Wake-up from
powersave mode
Initialise MSP430
Restore RF Channel and
Volume Level Defaults
Initialise MSP430
Should
communication be
established with
another unit?
No
Yes
Initialise CMX649 and CC1000
Begin Communications
No
Return to
powersave mode?
Yes
Go to powersave mode
Wait for Wake-up from
powersave mode
Figure 3 MSP430F147 Firmware Program Flow
6.2.3
Firmware Structure
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The firmware is event driven with time-critical functions being performed in interrupt routines.
There are four events that can cause an interrupt to be signalled:
•
•
•
•
The CMX649 is ready to transfer digital audio, one byte that has been encoded by the
CMX649, received by the MSP430F147, and one byte transmitted by the MSP430F147,
to be decoded by the CMX649. (Handled by firmware function “CMX649_TRANSFER”).
The CC1000 has received a byte from the RF link when in receive mode. (Handled by
firmware function “RFCHIPRX”).
The CC1000 is ready to transmit a byte over the RF link when in transmit mode.
(Handled by the firmware function “RFCHIPTX”).
The VOL-, VOL+ or CHNL button has been pressed. (Handled by the firmware functions
“BUTTON_DEBOUNCE” and “BUTTONS”).
As well as performing their own functions, the interrupt handlers can set flags to request that the
board:
•
•
•
•
Switches to RF receive mode or RF transmit mode.
Toggles the power state.
Changes the volume level
Exchanges a new RF channel to communicate on.
When a board is powered and communicating, the firmware function “MAINLOOP” continuously
executes so that when a flag is set “MAINLOOP” can call the appropriate subroutine to perform
the requested function, see Figure 4. These functions are performed by “MAINLOOP” as they
are less time critical than those performed by the interrupt handlers.
6.2.4
CMX649 Register Configuration
The firmware configures the CMX649 registers as follows:
Register Name
Register Address (hex)
Register Value (hex)
AAF/AIF BANDWIDTH
AUDIO INPUT LEVEL CTRL
POWER CONTROL 1
POWER CONTROL 2
CODEC MODE CONTROL
61
63
64
65
70
SCRAMBLER CONTROL
71
CLK DIVIDER CONTROL
CLK SOURCE CONTROL
CODEC INTERUPT CONTROL
DECODER MODE AND SETUP
DECODER ADM CONTROL
DECODE VAD THRESHOLD
DECODE OFF-SET LEVEL
ENCODER MODE AND SETUP
ENCODER ADM CONTROL
ENCODE VAD THRESHOLD
ENCODE OFF-SET LEVEL
72
73
81
D0
D1
D2
D3
E0
E1
E2
E3
00
C0
55
55
00
9xxx (where ‘xxx’ is a
random number
E340
30F8
88
01B8
4999
0400
0004
01B8
499A
0400
0004
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6.3
DE6491
Troubleshooting
Communication may be lost between two paired boards after a reset or reconnection of the power
supply to one of the boards. Both of these events will cause the RF channel that board uses for
communication to be reset to the default channel. Performing a reset on the other board will
force both boards to use the same default RF channel and communication can be re-established.
Figure 4 MAINLOOP Flow
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7.
Performance Specification
7.1
Electrical Performance
DE6491
7.1.1 Absolute Maximum Ratings
Exceeding these maximum ratings can result in damage to the Demonstration Kit.
Min.
-0.3
-0.3
0
-2
Supply (VIN - VSS)
Voltage on any connector pin to VSS
Current into or out of VIN and VSS pins
Current into or out of any other connector pin
Max.
6
3.0
+30
+2
Units
V
V
mA
mA
Max.
5.5
+35
865
Units
V
°C
MHz
7.1.2 Operating Limits
Correct operation of the Demonstration Kit outside these limits is not implied.
Notes
Supply (VIN - VSS)
Operating Temperature
Operating Frequency (RF)
Min.
2.9
+10
863
7.1.3 Operating Characteristics
VIN - VSS = 3.0V, Tamb = +25°C.
Notes
DC Parameters
IDD (powersave, Master)
IDD (powersave, Slave)
IDD (periodic wake from powersave, Master)
IDD (periodic wake from powersave, Slave)
IDD (powered and communicating, RF Range
setting = Minimum)
IDD (powered and communicating, RF Range
setting = Low)
IDD (powered and communicating, RF Range
setting = High)
IDD (powered and communicating, RF Range
setting = Maximum)
RF Range with:
RF Power Setting = Minimum
RF Power Setting = Low
RF Power Setting = High
RF Power Setting = Maximum
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Min.
Typ.
Max.
Units
–
–
–
–
–
500
420
2.1
13.0
17.0
–
–
–
–
–
µA
µA
mA
mA
mA
–
18.0
–
mA
–
20.0
–
mA
–
25.5
–
mA
–
–
–
–
–
–
–
–
3.0
8.0
12.0
20.0
m
m
m
m
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DE6491
CML does not assume any responsibility for the use of any circuitry described. No IPR or circuit patent licences are implied.
CML reserves the right at any time without notice to change the said circuitry and any part of this product specification. Evaluation
kits and demonstration boards are supplied for the sole purpose of demonstrating the operation of CML products and are supplied
without warranty. They are intended for use in a laboratory environment only and are not for re-sale, end-use or incorporation into
other equipments. Operation of these kits and boards outside a laboratory environment is not permitted within the European
Community. All software/firmware is supplied "as is" and is without warranty. It forms part of the product supplied and is licensed
for use only with this product, for the purpose of demonstrating the operation of CML products. Whilst all reasonable efforts are
made to ensure that software/firmware contained in this product is virus free, CML accepts no resonsibility whatsoever for any
contamination which results from using this product and the onus for checking that the software/firmware is virus free is placed on
the purchaser of this evaluation kit or development board.
www.cmlmicro.com
For FAQs see: www.cmlmicro.com/products/faqs/
For a full data sheet listing see: www.cmlmicro.com/products/datasheets/download.htm
For detailed application notes: www.cmlmicro.com/products/applications/
CML Microcircuits
(UK) Ltd
CML Microcircuits
(Singapore)Pte Ltd
CML Microcircuits
(USA) Inc.
COMMUNICATION SEMICONDUCTORS
Oval Park, Langford, Maldon,
Essex,
CM9 6WG - England.
4800 Bethania Station Road,
Winston-Salem,
NC 27105 - USA.
No 2 Kallang Pudding Road,
#09 to 05/06 Mactech
Industrial Building,
Singapore 349307
No. 218, Tian Mu Road
West, Tower 1, Unit 1008,
Shanghai Kerry Everbright
City, Zhabei,
Shanghai 200070,
China.
Tel: +44 (0)1621 875500
Tel: +65 6745 0426
Fax: +44 (0)1621 875600
Tel: +1 336 744 5050,
800 638 5577
Fax: +1 336 744 5054
Fax: +65 6745 2917
Tel: +86 21 6317 4107
+86 21 6317 8916
Fax: +86 21 6317 0243
Sales:
sales@cmlmicro.com
Sales:
us.sales@cmlmicro.com
Sales:
sg.sales@cmlmicro.com
Sales:
cn.sales@cmlmicro.com.cn
Technical Support:
techsupport@cmlmicro.com
Technical Support:
us.techsupport@cmlmicro.com
Technical Support:
sg.techsupport@cmlmicro.com
Technical Support:
sg.techsupport@cmlmicro.com