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Analog Ground

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Chapter 2: Hardware Interface Description Analog Ground The C24 interface incorporates a dedicated analog ground contact, AGND pin 59, which is internally connected to the C24's ground. The AGND signal is intended to provide a separate ground connection for the application's external audio devices and circuits. This signal provides an isolated ground connection directly from C24, which is separated from the noisy digital ground of the application. It is recommended to connect this signal to analog audio devices and circuits used by the application. Using a separate analog ground minimizes audio noises and improves the audio circuit's immunity from external interferences. December 15, 2008 C24 Module Hardware Description 37

Section	Page
Table of Contents	5
List of Figures	9
List of Tables	10
Preface	11
Manual Scope	11
Target Audience	11
Manual Organization	11
Applicable Documents	12
Regulatory Requirements	12
Safety Statement and Requirements	12
Antenna and Transmission Safety Precautions	13
Standards	13
Contact Us	14
Text Conventions	14
Field Service	16
General Safety	16
Caring for the Environment	17
Limitation of Liability	19
Warranty Notification	20
How to Get Warranty Service?	20
Claiming	21
Conditions	21
What is Not Covered by the Warranty	22
Installed Data	22
Out of Warranty Repairs	22
Revision History	23
Chapter 1: Introduction	25
Product Specifications	26
Certifications Approvals	28
Regulatory Approvals	29
CFR 47 Part 15.19 specifies label requirements	29
CFR 47 Part 15.21 Information to user	29
CFR 47 Part 15.105 Information to the user	29
Chapter 2: Hardware Interface Description	31
Architecture Overview	31
Digital Block	32
Analog Block	32
CDMA Transceiver Block	32
Operating Modes	33
Power Supply	34
Power Supply Design	34
Power Consumption	35
Power On/Off Operation	36
Turning the C24 On	36
Turning the C24 On Using ON_N	36
Turning the C24 On Using IGN	37
Turning the C24 Off	37
Turning the C24 Off Using ON_N	37
Turning the C24 Off Using IGN	38
Turning the C24 Off Using AT+MRST	39
Power Loss shut down	39
Low Power Mode	40
Activating Low Power Mode	40
Serial Interface During Low Power Mode	41
Terminating Low Power Mode	41
Temporary Termination of Low Power Mode	42
Permanent termination of Low Power Mode	43
Real Time Clock	44
Serial Interfaces	45
Primary UART (UART1)	45
Secondary UART (UART2)	45
USB Interface	46
UIM Interface	47
UIM Connection	47
UIM Design Guidelines	48
Audio Interface	49
Handset Microphone Port	49
Headset Microphone Port	50
Speaker Port	51
Headset Detection	53
Alert Loudspeaker Port	54
Digital Audio Interface	55
Operating Modes	56
Basic Mode	56
Advanced Mode	56
Audio Programming Interface	57
Audio Algorithms	58
Gain Control	59
Audio Design	60
Analog Ground	61
A/D Interface	62
General Purpose A/D	62
Power Supply A/D	62
Controls and Indicators Interface	64
Reset	64
VREF Reference Regulator	64
Wakeup Out	65
Antenna Detection	67
CDMA Network Indicator	67
Transmission Indicator	67
General Purpose I/O	67
GPS Interface	68
Antenna Interface	69
Chapter 3: Electrical and Environmental Specifications	71
Absolute Maximum Ratings	71
Environmental Specifications	72
Application Interface Specifications	72
Chapter 4: Mechanical Specifications	79
Board Dimensions	79
Interface Connector Specifications	80
Mating Connector	81
RF Connector Specifications	82
Mating Connector	82
C24 Mounting	84
Chapter 5: Service and Testing	85
Service	85
Who to Contact?	85
Required Query Information	85
Motorola Workflow	86
Service Centers	87
Testing a Standalone Unit	88
Test Setup	88
Test Procedure	90
Acronyms and Abbreviations	91
A	91
B	91
C	91
D	91
E	91
F	92
G	92
H	92
I	92
L	92
M	92
O	92
P	92
R	93
S	93
T	93
U	94
V	94
Index	95
A	95
B	95
C	95
E	95
O	95
P	95
R	95
S	95
T	95

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Chapter 2: Hardware Interface Description

December 15, 2008

C24 Module Hardware Description

Analog Ground

The C24 interface incorporates a dedicated analog ground contact, AGND pin 59, which is

internally connected to the C24's ground. The AGND signal is intended to provide a separate

ground connection for the application's external audio devices and circuits.

This signal provides an isolated ground connection directly from C24, which is separated from

the noisy digital ground of the application. It is recommended to connect this signal to analog

audio devices and circuits used by the application. Using a separate analog ground minimizes

audio noises and improves the audio circuit's immunity from external interferences.