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LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
Product name
LS20229 series
Description
Stand-alone GPS smart antenna module/SS4,4800BPS
Version
1.0
Datasheet of stand-alone GPS smart antenna module, LS20229
1
Introduction
LS20229 series are complete stand-alone GPS smart antenna modules, including embedded
patch antenna and GPS receiver circuits. The module is powered by SiRF Star IV, it can provide you
with superior sensitivity and performance even in urban canyon and dense foliage environment. With
SiRF CGEE (Client Generated Extended Ephemeris) technology, it reliably predicts satellite
positions for 3 days that are stored in the on-board EEPROM and delivers CGEE-start time of less
than 15 seconds under most conditions, without any network assistance.
2
Features
3
SiRF Star IV high sensitivity solution
Support 48-channel GPS
Fast TTFF at low signal level
Built-in active jammer remover to track up to 8 CW jammers
Embedded free CGEE technology to get faster location fix
Capable of SBAS (WAAS, EGNOS, MSAS, GAGAN) (supported in the future)
Micro Power Mode (supported in the future)
Application
GPS tracker
Digital cameras and digital video recorder with GPS function
Mobile internet device with GPS function
Page 1/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
RTC
TCXO
GPS antenna
VCC
LNA
TX
SiRF
GPS chip
RX
SAW
WAKEUP
ESD
protection
ON_OFF
EEPROM
LS20229
Fig 3-1 System block diagram of LS20229
VCC
GND
TX
RX
ON_OFF
WAKEUP
Connector for LS20229
Keep alive to get
hot start and CGEE
1.8V
Beads
VCC IO
GND
1.8V
(close to connector)
RX
TX
OUTPUT
INPUT
Micro processor
Fig 3-2 Typical application circuit
Page 2/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
Fig 3-3 Use level shifters for a micro processor of 3.3V IO voltage to communicate with
LS20229.
Note: The signals of TX, RX, ON_OFF and WAKEUP must be taken carefully in order not
to radiate interference. It is better to add beads or low-pass filters on these signals.
Page 3/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
4
GPS receiver and antenna
4.1 GPS receiver
Chip
SiRF Star IV, GSD4e-9302
Frequency
L1 1575.42MHz, C/A code
Channels
Support 48 channels
Update rate
1Hz
Hot start (Open Sky)
Acquisition Time
Cold Start (Open Sky)
< 1s
32s (typical)
< 15s (typical), CGEE-start
Position Accuracy
Autonomous
3m (2D RMS)
SBAS
2.5m (depends on accuracy of correction data)
Datum
WGS-84 (default)
Max. Altitude
< 18,000 m
Max. Velocity
< 515 m/s
4800 bps (1), 8 data bits, no parity, 1 stop bits (default)
Protocol
NMEA 0183 ver 3.0
1Hz: GGA, GSA, RMC
0.2Hz: GSV
Note 1: Both baud rate and output message rate are configurable by software command.
4.2 GPS antenna
Model
LS20229-A
LS20229-B
Antenna type
Patch antenna (3.5mm thickness)
Patch antenna (2mm thickness)
Polarization
RHCP
RHCP
Frequency Range
1575.42MHz ± 1.023MHz (1)
1575.42MHz ± 1.023MHz (1)
Gain
-3 dBic Typ. @zenith (1)
-4.6 dBic Typ. @zenith (1)
Axial ratio
Max 4.0dB @zenith (1)
Max 4.0dB @zenith (1)
Note 1: This value is measured with evaluation board and must be retuned when installed into your device.
Page 4/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
Fig 4-1 LS20229-A is installed on the evaluation board and tested in the open-sky field.
Fig 4-2 GPS receiving performance of LS20229-A as Fig 4-1.
Page 5/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
Fig 4-3 LS20229-B is installed on the evaluation board and tested in the open-sky field.
Fig 4-4 GPS receiving performance of LS20229-B as Fig 4-3.
Page 6/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
5
Software interface
5.1 NMEA output message
Table 5.1-1 NMEA output message
NMEA record
Description
GGA
Global positioning system fixed data
GLL
Geographic position - latitude/longitude
GSA
GNSS DOP and active satellites
GSV
GNSS satellites in view
RMC
Recommended minimum specific GNSS data
VTG
Course over ground and ground speed
GGA--- Global Positioning System Fixed Data
Table 5.1-2 contains the values for the following example:
$GPGGA,053740.000,2503.6319,N,12136.0099,E,1,08,1.1,63.8,M,15.2,M,,0000*64
Table5.1- 2 GGA Data Format
Name
Example
Message ID
$GPGGA
GGA protocol header
UTC Time
053740.000
hhmmss.sss
Latitude
2503.6319
ddmm.mmmm
N/S indicator
N
N=north or S=south
Longitude
12136.0099
dddmm.mmmm
E/W Indicator
E
E=east or W=west
Position Fix Indicator
1
See Table 5.1-3
Satellites Used
08
Range 0 to 12
HDOP
1.1
Horizontal Dilution of Precision
MSL Altitude
63.8
mters
Units
M
mters
Geoid Separation
15.2
mters
Units
M
mters
Age of Diff. Corr.
Units
second
Diff. Ref. Station ID
0000
Checksum
*64
<CR> <LF>
Description
Null fields when DGPS is not used
End of message termination
Table 5.1-3 Position Fix Indicators
Value
Description
0
Fix not available or invalid
Page 7/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
1
GPS SPS Mode, fix valid
2
Differential GPS, SPS Mode, fix valid
3-5
Not supported
6
Dead Reckoning Mode, fix valid
GLL--- Geographic Position – Latitude/Longitude
Table 5.1-4 contains the values for the following example:
$GPGLL,2503.6319,N,12136.0099,E,053740.000,A,A*52
Table 5.1-4 GLL Data Format
Name
Example
Units
Message ID
$GPGLL
GLL protocol header
Latitude
2503.6319
ddmm.mmmm
N/S indicator
N
N=north or S=south
Longitude
12136.0099
dddmm.mmmm
E/W indicator
E
E=east or W=west
UTC Time
053740.000
hhmmss.sss
Status
A
A=data valid or V=data not valid
Mode
A
A=autonomous, D=DGPS, E=DR
Checksum
*52
<CR> <LF>
Description
End of message termination
GSA---GNSS DOP and Active Satellites
Table 5.1-5 contains the values for the following example:
$GPGSA,A,3,24,07,17,11,28,08,20,04,,,,,2.0,1.1,1.7*35
Table 5.1-5 GSA Data Format
Name
Example
Message ID
$GPGSA
GSA protocol header
Mode 1
A
See Table 5.1-6
Mode 2
3
See Table 5.1-7
ID of satellite used
24
Sv on Channel 1
ID of satellite used
07
Sv on Channel 2
Units
Description
….
….
ID of satellite used
Sv on Channel 12
PDOP
2.0
Position Dilution of Precision
HDOP
1.1
Horizontal Dilution of Precision
VDOP
1.7
Vertical Dilution of Precision
Checksum
*35
Page 8/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
<CR> <LF>
End of message termination
Table 5.1-6 Mode 1
Value
Description
M
Manual- forced to operate in 2D or 3D mode
A
Automatic-allowed to automatically switch 2D/3D
Table 5.1-7 Mode 2
Value
Description
1
Fix not available
2
2D
3
3D
GSV---GNSS Satellites in View
Table 5.1-8 contains the values for the following example:
$GPGSV,3,1,12,28,81,285,42,24,67,302,46,31,54,354,,20,51,077,46*73
$GPGSV,3,2,12,17,41,328,45,07,32,315,45,04,31,250,40,11,25,046,41*75
$GPGSV,3,3,12,08,22,214,38,27,08,190,16,19,05,092,33,23,04,127,*7B
Table 5.1-8 GSV Data Format
Name
Example
Message ID
Units
Description
$GPGSV
GSV protocol header
Total number of messages
3
Range 1 to 3
Message number1
1
Range 1 to 3
Satellites in view
12
Satellite ID
28
Elevation
81
degrees
Channel 1 (Range 00 to 90)
Azimuth
285
degrees
Channel 1 (Range 000 to 359)
SNR (C/No)
42
dB-Hz
Channel 1 (Range 00 to 99, null when not tracking)
Satellite ID
20
Elevation
51
degrees
Channel 4 (Range 00 to 90)
Azimuth
077
degrees
Channel 4 (Range 000 to 359)
SNR (C/No)
46
dB-Hz
Channel 4 (Range 00 to 99, null when not tracking)
Checksum
*73
1
Channel 1 (Range 01 to 32)
Channel 4 (Range 01 to 32)
<CR> <LF>
End of message termination
1. Depending on the number of satellites tracked multiple messages of GSV data may be required.
RMC---Recommended Minimum Specific GNSS Data
Table 5.1-9 contains the values for the following example:
$GPRMC,053740.000,A,2503.6319,N,12136.0099,E,2.69,79.65,100106,,,A*53
Page 9/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
Table 5.1-9 RMC Data Format
Name
Example
Units
Message ID
$GPRMC
RMC protocol header
UTC Time
053740.000
hhmmss.sss
Status
A
A=data valid or V=data not valid
Latitude
2503.6319
ddmm.mmmm
N/S Indicator
N
N=north or S=south
Longitude
12136.0099
dddmm.mmmm
E/W Indicator
E
E=east or W=west
Speed over ground
2.69
knots
Course over ground
79.65
degrees
Date
100106
True
ddmmyy
degrees
Magnetic variation
Variation sense
E=east or W=west (Not shown)
Mode
A
Checksum
*53
A=autonomous, D=DGPS, E=DR
<CR> <LF>
Description
End of message termination
VTG---Course Over Ground and Ground Speed
Table 5.1-10 contains the values for the following example:
$GPVTG,79.65,T,,M,2.69,N,5.0,K,A*38
Table 5.1-10 VTG Data Format
Name
Example
Message ID
$GPVTG
Course over ground
79.65
Reference
T
Units
VTG protocol header
degrees
Measured heading
True
degrees
Course over ground
Description
Measured heading
Reference
M
Magnetic
Speed over ground
2.69
Units
N
Speed over ground
5.0
Units
K
Kilometer per hour
Mode
A
A=autonomous, D=DGPS, E=DR
Checksum
*38
knots
Measured speed
Knots
km/hr
<CR> <LF>
Measured speed
End of message termination
5.2 Proprietary NMEA input message
Page 10/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
Table 5.2-1 Message Parameters
Start Sequence
$PSRF<MID>
Payload
1
Data
Checksum
2
*CKSUM
End Sequence
3
<CR><LF>4
1.
Message Identifier consisting of three numeric characters. Input messages begin at MID 100.
2.
Message specific data. Refer to a specific message section for <data>…<data> definition.
3.
CKSUM is a two-hex character checksum as defined in the NMEA specification, NMEA-0183Standard For
Interfacing Marine Electronic Devices. Use of checksums is required on all input messages.
4.
Each message is terminated using Carriage Return (CR) Line Feed (LF) which is \r\n which is hex 0D0A. Because
\r\n are not printable ASCII characters, they are omitted from the example strings, but must be sent to terminate the
message and cause the receiver to process that input message.
Note: All fields in all proprietary NMEA messages are required, none are optional. All NMEA messages are comma
delimited.
Table 5.2-2 Proprietary NMEA input messages
MID1
Message
Description
SetSerialPort
100
Set PORT A parameters and protocol
NavigationInitialization
101
Parameters required for start using X/Y/Z2
SetDGPSPort
102
Set PORT B parameters for DGPS input
Query/Rate Control
103
Query standard NMEA message and/or set output rate
LLANavigationInitialization
104
Parameters required for start using Lat/Lon/Alt3
Development Data On/Off
105
Development Data messages On/Off
Select Datum
106
Selection of datum to be used for coordinate transformations
1.
Message Identification (MID).
2.
Input coordinates must be WGS84.
3.
Input coordinates must be WGS84
100---SetSerialPort
This command message is used to set the protocol (SiRF binary or NMEA) and/or the communication parameters (Baud,
data bits, stop bits, and parity). Generally, this command is used to switch the module back to SiRF binary protocol mode
where a more extensive command message set is available. When a valid message is received, the parameters are stored
in battery-backed SRAM and the Evaluation Receiver restarts using the saved parameters.
Table 5.2-3 contains the input values for the following example:
Switch to SiRF binary protocol at 9600,8,N,1
$PSRF100,0,9600,8,1,0*0C
Table 5.2-3 Set Serial Port Data Format
Name
Example
Message ID
$PSRF100
Units
Description
PSRF100 protocol header
Page 11/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
Protocol
0
0=SiRF binary, 1=NMEA
Baud
9600
4800,9600,19200,38400,57600,115200
DataBits
8
8,71
StopBits
1
0,1
Parity
0
0=None, 1=Odd, 2=Even
Checksum
*0C
<CR><LF>
End of message termination
1. SiRF protocol is only valid for 8 data bits, 1 stop bit, and no parity.
101---NavigationInitialization
This command is used to initialize the Evaluation Receiver by providing current position (in X, Y, Z coordinates), clock
offset, and time. This enables the Evaluation Receiver to search for the correct satellite signals at the correct signal
parameters. Correct initialization parameters enable the Evaluation Receiver to acquire signals quickly.
Table 5.2-4 contains the input values for the following example:
Start using known position and time
$PSRF101,-2686700,-4304200,3851624,96000,497260,921,12,3*1C
Table 5.2-4 Navigation Initialization Data Format
Name
Example
Units
Description
Message ID
$PSRF101
ECEF X
-2686700
meters
X coordinate position
ECEF Y
-4304200
meters
Y coordinate position
ECEF Z
3851624
meters
Z coordinate position
ClkOffset
96000
Hz
Clock Offset of the Evaluation Receiver1
TimeOfWeek
497260
seconds
GPS Time Of Week
WeekNo
921
GPS Week Number
ChannelCount
12
Range 1 to 12
ResetCfg
3
See Table 5.2-5
Checksum
*1C
PSRF101 protocol header
<CR><LF>
End of message termination
1. Use 0 for last saved value if available. If this is unavailable, a default value of 96000 is used.
Table 5.2-5 Reset Configuration
Hex
Description
0x01
Hot Start – All data valid
0x02
Warm Start – Ephemeris cleared
0x03
Warm Start (with Init) – Ephemeris cleared, initialization data loaded
0x04
Cold Start – Clears all data in memory
Page 12/24
© 2011 LOCOSYS Technology Inc.
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20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
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0x08
Clear Memory – Clears all data in memory and resets the receiver back to factory defaults
102---SetDGPSPort
This command is used to control the serial port used to receive RTCM differential corrections. Differential receivers may
output corrections using different communication parameters. If a DGPS receiver is used that has different
communication parameters, use this command to allow the receiver to correctly decode the data. When a valid message
is received, the parameters are stored in battery-backed SRAM and the receiver restarts using the saved parameters.
Table 5.2-6 contains the input values for the following example:
Set DGPS Port to be 9600,8,N,1.
$PSRF102,9600,8,1,0*12
Table 5.2-6 Set GPS Port Data Format
Name
Example
Units
Message ID
$PSRF102
PSRF102 protocol header
Baud
9600
4800,9600,19200,38400
DataBits
8
8,7
StopBits
1
0,1
Parity
0
0=None, 1=Odd, 2=Even
Checksum
*12
<CR><LF>
Description
End of message termination
Note: RTCM is not supported.
103---Query/Rate Control
This command is used to control the output of standard NMEA messages GGA, GLL, GSA, GSV, RMC, and VTG.
Using this command message, standard NMEA messages may be polled once, or setup for periodic output. Checksums
may also be enabled or disabled depending on the needs of the receiving program. NMEA message settings are saved in
battery-backed memory for each entry when the message is accepted.
Table 5.2-7 contains the input values for the following example:
1. Query the GGA message with checksum enabled
$PSRF103,00,01,00,01*25
2. Enable VTG message for a 1 Hz constant output with checksum enabled
$PSRF103,05,00,01,01*20
3. Disable VTG message
$PSRF103,05,00,00,01*21
Table 5.2-7 Query/Rate Control Data Format (See example 1)
Name
Example
Units
Description
Message ID
$PSRF103
PSRF103 protocol header
Msg
00
See Table 5.2-8
Page 13/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
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Mode
01
Rate
00
CksumEnable
01
Checksum
*25
0=SetRate, 1=Query
seconds
Output – off=0, max=255
0=Disable Checksum, 1=Enable Checksum
<CR><LF>
End of message termination
Table 5.2-8 Messages
Description
Value
0
GGA
1
GLL
2
GSA
3
GSV
4
RMC
5
VTG
6
MSS (If internal beacon is supported)
7
Not defined
8
ZDA (if 1PPS output is supported)
9
Not defined
104---LLANavigationInitialization
This command is used to initialize the Evaluation Receiver by providing current position (in latitude, longitude, and
altitude coordinates), clock offset, and time. This enables the receiver to search for the correct satellite signals at the
correct signal parameters. Correct initialization parameters enable the receiver to acquire signals quickly.
Table 5.2-9 contains the input values for the following example:
Start using known position and time.
$PSRF104,37.3875111,-121.97232,0,96000,237759,1946,12,1*07
Table 5.2-9 LLA Navigation Initialization Data Format
Name
Example
Units
Description
Message ID
$PSRF104
Lat
37.3875111
degrees
Latitude position (Range 90 to –90)
Lon
-121.97232
degrees
Longitude position (Range 180 to –180)
Alt
0
meters
Altitude position
ClkOffset
96000
Hz
Clock Offset of the Evaluation Receiver1
TimeOfWeek
237759
seconds
GPS Time Of Week
WeekNo
1946
Extended GPS Week Number (1024 added)
ChannelCount
12
Range 1 to 12
ResetCfg
1
See Table 5.2-10
PSRF104 protocol header
Page 14/24
© 2011 LOCOSYS Technology Inc.
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Checksum
*07
<CR><LF>
End of message termination
1. Use 0 for last saved value if available. If this is unavailable, a default value of 96000 is used.
Table 5.2-10 Messages
Hex
0x01
Hot Start – All data valid
0x02
Warm Start – Ephemeris cleared
0x03
0x04
0x08
Description
Warm Start (with Init) – Ephemeris cleared,
initialization data loaded
Cold Start – Clears all data in memory
Clear Memory – Clears all data in memory
and resets receiver back to factory defaults
105---Development Data On/Off
Use this command to enable development data information if you are having trouble getting commands accepted. Invalid
commands generate debug information that enables you to determine the source of the command rejection. Common
reasons for input command rejection are invalid checksum or parameter out of specified range.
Table 5.2-11 contains the input values for the following example:
1. Debug On
$PSRF105,1*3E
2. Debug Off
$PSRF105,0*3F
Table 5.2-11 Development Data On/Off Data Format
Name
Example
Message ID
$PSRF105
PSRF105 protocol header
Debug
1
0=Off, 1=On
Checksum
*3E
<CR><LF>
Units
Description
End of message termination
106---Select Datum
$PSGPS receivers perform initial position and velocity calculations using an earth-centered earth-fixed (ECEF)
coordinate system. Results may be converted to an earth model (geoid) defined by the selected datum. The default datum
is WGS 84 (World Geodetic System 1984) which provides a worldwide common grid system that may be translated into
local coordinate systems or map datums. (Local map datums are a best fit to the local shape of the earth and not valid
worldwide.)
Table 5.2-12 contains the input values for the following example:
Datum select TOKYO_MEAN
Page 15/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
$PSRF106,178*32
Table 5.2-12 Development Data On/Off Data Format
Name
Example
Units
Description
Message ID
$PSRF106
PSRF106 protocol header
Datum
178
21=WGS84
178=TOKYO_MEAN
179=TOKYO_JAPAN
180=TOKYO_KOREA
181=TOKYO_OKINAWA
Checksum
*32
<CR><LF>
End of message termination
117---System Turn Off
This message requests that the GPS receiver perform an orderly shutdown and switch to hibernate mode.
Table 5.2-13 contains the values for the following example:
$PSRF117,16*0B
Table 5.2-13 System Turn Off
Name
Example
Message ID
$PSRF117
PSRF117 protocol header
Sub ID
16
16: System turn off
Checksum
*0B
<CR><LF>
Units
Description
End of message termination
Page 16/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
5.3 Supply voltage control and sequencing
5.3.1 Initial power up
When power is first applied, the module goes into a low-power mode while RTC starts. The
host is not required to control /RESET pin (pin 8 of GPS module) since the module’s internal
reset circuitry handles detection of application of power. After that, the module is in
“ready-to-start” state and awaits an ON_OFF input pulse to start.
Since RTC startup time is variable, detection of when the module is ready to accept an
ON_OFF pulse requires the host to either wait for a fixed interval or to monitor a pulse on
WAKEUP output (pin 9 of GPS module) to assert a pulse on the ON_OFF input. An example
flow chart is shown below.
Start
First provide power
to GPS module
Wait for
≧1 second
≧ 3 RTC cycles
Assert an ON_OFF
pulse to GPS module
No
Receive UART
messages from GPS
module within 1
second?
ON_OFF pulse
Yes
GPS module starts to
work in full-power
mode
End
Page 17/24
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886-2-8698-3699
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5.3.2 Procedure for removing power of GPS module
Abrupt, uncontrolled removal of power while GPS module is operating carries the risk of
data corruption. The consequences of corruption range from longer TimeToFirstFix to complete
system failure. The appropriate procedure to remove power is shown as below.
Start
Via software
“
Via ON_OFF pin
”
Assert an ON_OFF pulse
when GPS module is in
full-power mode
Send system turn off
message to GPS module
(refer to table 5.2-13)
≧
Wait for 1 second to
let GPS module go into
hibernate mode
Remove power of GPS
module for a period
longer than 10 s
Restart GPS
module?
Note: All BBRAM contents and
RTC time of GPS module will
be lost resulting in a factory
reset.
Yes
Follow the procedure of
section 5.3.1
No
End
Page 18/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
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Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
6
Pin assignment and descriptions
Pin # Name
Type Description
1
VCC
P
DC supply voltage
2
GND
P
Ground
3
TX
O
Serial data output
4
RX
I
Serial data input
5
ON_OFF
I
Note
1
Power control pin.
1,2
Internal 10KΩ pull-down resistor.
Wake up output.
6
WAKEUP
O
A high on this output indicates that GPS module is in operational
mode. A low on this output indicates that GPS module is in low
power state (standby, hibernate and ready-to-start). User can use
this pin to control external power supply.
<Note>
1. Input voltage is 3.6V tolerant.
2. Input pulse to start the module, and switch the module between different power modes.
ON_OFF pulse requires a rising edge and high level that persists for three cycles of the RTC clock
in order to be detected. Resetting the ON_OFF detector requires that ON_OFF goes to logic low for
at least three cycles of the RTC clock.
If the module is first powered, i.e. in “ready-to-start” state, an ON_OFF pulse will start the module.
If the module is in hibernate state, an ON_OFF pulse will move it to full-power mode.
If the module is in MicroPower mode, an ON_OFF pulse will move it to full-power mode.
If the module is in AdvancedPower mode, an ON_OFF pulse will initiate one AdvancedPower cycle.
If the module is in TricklePower mode, an ON_OFF pulse will initiate one TricklePower cycle.
If the module is in Push-To-Fix mode, an ON_OFF pulse will initiate one Push-To-Fix cycle.
If the module is already in full-power mode, an ON_OFF pulse will initiate orderly shutdown.
Page 19/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
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Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
7
Ordering information
LS20229 series products are available with different thickness GPS antenna. The order
number is as below table.
Model
GPS antenna
8
LS20229-A
LS20229-B
3.5mm thickness
2mm thickness
DC & Temperature characteristics
8.1 Absolute maximum ratings
Parameter
Symbol
Ratings
Units
Supply Voltage
VCC
1.95
V
Operating Temperature Range
Topr
-40 ~ 85
℃
Storage Temperature Range
Tstg
-40 ~ 85
℃
8.2 DC Electrical characteristics
Parameter
Supply Voltage
Supply Current
Symbol
Conditions
Min.
Typ.
Max.
Units
1.71
1.8
1.89
V
Full operation
39(1)
120
mA
Standby(2)
65
uA
Hibernate
14
uA
Ready-to-start(3)
8
uA
MPM(4)
500
uA
VCC
IVCC
High Level Input Voltage
VI H
0.7*VCC
3.6
V
Low Level Input Voltage
VI L
-0.4
0.45
V
High Level Output Voltage
VOH
0.75*VCC
VCC
V
Low Level Output Voltage
VOL
0.4
V
High Level Output Current
I OH
2
mA
Low Level Output Current
I OL
2
mA
<Note>
1.
Measured when position fix is available and input voltage is 1.8V.
2.
Transitional state when GPS module is in TricklePower mode.
3.
When power is first applied, the module goes into a “ready-to-start” state. Please refer to the section 5.3.
4.
MicroPowerMode.
8.3 Temperature characteristics
Parameter
Operating Temperature
Symbol
Min.
Typ.
Max.
Units
Topr
-30
-
85
℃
Page 20/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
Storage Temperature
9
Tstg
-40
25
85
℃
Mechanical specification
9.1 Outline dimensions
9.1.1 LS20229-A
9.1.2 LS20229-B
Page 21/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
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℡ 886-2-8698-3698
886-2-8698-3699
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9.2 Applicable FPC/FFC cable
Page 22/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
10 Packing information
Page 23/24
© 2011 LOCOSYS Technology Inc.
LOCOSYS Technology Inc.
20F.-13, No.79, Sec. 1, Xintai 5th Rd.,
Xizhi City, Taipei County 221, Taiwan
℡ 886-2-8698-3698
886-2-8698-3699
www.locosystech.com
Document change list
Revision 1.0
First release on June 29, 2011
Page 24/24
© 2011 LOCOSYS Technology Inc.
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