Quectel LG77L EVB User manual

LG77L EVB User Guide
GNSS Module Series
Version: 1.0.0
Date: 2020-12-03
Status: Preliminary
www.quectel.com

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About the document
Revision History
Version
Date
Author
Description
-
2020-12-03
Wind ZHAO
Creation of the document
1.0.0
2020-12-03
Wind ZHAO
Preliminary

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Contents
About the document ...................................................................................................................................3
Contents.......................................................................................................................................................4
Table Index...................................................................................................................................................5
Figure Index.................................................................................................................................................6
1Introduction..........................................................................................................................................7
1.1. Safety Information.......................................................................................................................7
2General Overview.................................................................................................................................8
2.1. Top and Bottom Views................................................................................................................8
2.2. Key Features...............................................................................................................................9
2.3. EVB KitAccessories .................................................................................................................10
3Application Interfaces .......................................................................................................................11
3.1. Micro-USB Interface..................................................................................................................11
3.2. Antenna Interface...................................................................................................................... 11
3.3. Switches and Buttons ...............................................................................................................12
3.4. Operation Status Indication LEDs.............................................................................................13
3.5. Test Points.................................................................................................................................14
4EVB and Accessories Assembly......................................................................................................15
5EVB Operation Procedures...............................................................................................................16
5.1. Communication via USB Interface............................................................................................16
5.2. Firmware Upgrade....................................................................................................................17
6Usage of PowerGPS ..........................................................................................................................18
6.1. PowerGPS Interface.................................................................................................................18
6.1.1. COM Port and Baud Rate Setting..................................................................................18
6.1.2. Explanations of PowerGPS Interface ............................................................................19
6.2. Command Sending...................................................................................................................20
6.3. TTFF Testing.............................................................................................................................21
7Appendix A References.....................................................................................................................26

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Table Index
Table 1: Interfaces of LG77L EVB................................................................................................................ 8
Table 2: Key Features of LG77L EVB.......................................................................................................... 9
Table 3: List of Accessories........................................................................................................................ 10
Table 4: LG77L Switches and Buttons....................................................................................................... 13
Table 5: Operation Status Indication LEDs................................................................................................13
Table 6: Pin Description of J106 ................................................................................................................ 14
Table 7: Explanations of PowerGPS Interface........................................................................................... 19
Table 8: Related Documents......................................................................................................................26
Table 9: Terms and Abbreviations..............................................................................................................26

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Figure Index
Figure 1: Top View of LG77L EVB................................................................................................................8
Figure 2: EVB Kit Accessories ...................................................................................................................10
Figure 3: Micro-USB Interface.....................................................................................................................11
Figure 4: LG77L EVBAntenna Interface....................................................................................................12
Figure 5: LG77L EVB Switches and Buttons.............................................................................................12
Figure 6: Operation Status Indication LEDs ..............................................................................................13
Figure 7: LG77L EVB Test Points - J106 ...................................................................................................14
Figure 8: LG77L EVB and Accessories Assembly..................................................................................... 15
Figure 9: USB Ports ...................................................................................................................................16
Figure 10: COM Port Setting Interface of QCOM...................................................................................... 16
Figure 11: Firebird Update FW Tool Configurations for Firmware Upgrade..............................................17
Figure 12: PowerGPS main Interface (no connection)..............................................................................18
Figure 13: COM Port and Baud Rate Selection PowerGPS main Interface (connected) .........................19
Figure 14: Command Sending via PowerGPS ..........................................................................................21
Figure 15：Testing static TTFF Via uSTAR .............................................................................................. 22
Figure 16：Reference Location Button......................................................................................................23
Figure 17：Use Mean Position Button.......................................................................................................23
Figure 18：Config Button...........................................................................................................................24
Figure 19：Configurating TTFF Time-out (Sec)........................................................................................ 25

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1Introduction
This document defines and specifies the usage of LG77L EVB (Evaluation Board) which is an assistant
tool for engineers to develop and test Quectel LG77L module.
1.1. Safety Information
The following safety precautions must be observed during all phases of operation, such as usage, service
or repair of any cellular terminal or mobile incorporating LG77L. Manufacturers of the cellular terminal
should send the following safety information to users and operating personnel, and incorporate these
guidelines into all manuals supplied with the product. If not so, Quectel assumes no liability for customers’
failure to comply with these precautions.
Ensure the use of the product conforms to the local safety and environment
regulations and is allowed to be used in the country and in the required
environment.
Keep away from explosive and flammable materials. The use of electronic
products in extreme power supply conditions and locations with potentially
explosive atmospheres may cause fire and explosion accidents.
The product must be powered by a stable voltage source, while the wiring must
comply with security precautions and fire prevention regulations.
Proper ESD handling procedures must be followed throughout the mounting,
handling and operation of any application that incorporates the module to avoid
ESD damages.

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2General Overview
2.1. Top and Bottom Views
The following figure shows the top view of LG77L EVB.
B
D
E
F
G
A
H
F
C
Figure 1: Top View of LG77L EVB
Table 1: Interfaces of LG77L EVB
SN.
Reference Number
Description
A
J401
Test points
B
S402
FORCE_ON button

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2.2. Key Features
The following table describes the detailed features of LG77L EVB.
Table 2: Key Features of LG77L EVB
C
S401
RESET button
D
S201
POWER switch
E
J102
Micro USB interface
F
D402, D403
Indication LEDs
G
J301
Antenna interface
H
U101
LG77L module
Features
Implementation
Power Supply
DC power supply (J201): 4.5–5.5 V, typically: 5.0 V
Micro-USB Interface
Power supply and NEMA sentence output
Signal Indication
2 LEDs are available for signal indication
Switches and Buttons
POWER Switch (S201)
RESET (S401)
FORCE_ON (S402)
Physical Characteristics
Size: 70 mm ×70 mm

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2.3. EVB Kit Accessories
GNSS
Antenna
USB Flash
Drive
EVB
USB Cable
Bolts and
Coupling Nuts
Figure 2: EVB Kit Accessories
Table 3: List of Accessories
Items
Description
Quantity
EVB
LG77L EVB
1
USB Cable
USB cable
1
GNSS Antenna
Active GNSS antenna
1
USB Flash Drive
GNSS EVB Micro-USB Driver CP210x
1
Instruction Sheet
A sheet of paper giving instructions for EVB
connection, details of EVB accessories, etc.
1
Others
Bolts and coupling nuts
4 for each type

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3Application Interfaces
3.1. Micro-USB Interface
The main power is supplied via a Micro-USB interface. Micro-USB interfaces can be used for data
communication. So, it is strongly recommended to use the Micro-USB interface for both power supply and
NEMA sentence output, during which only a USB cable is needed.
Micro-USB
Interface
Figure 3: Micro-USB Interface
3.2. Antenna Interface
The LG77L module can be connected to a dedicated passive or active GNSS antenna and it has a built-in
LNA to improve sensitivity. The antenna interface is used for connection with an external antenna.

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Antenna
Interface
Figure 4: LG77L EVB Antenna Interface
3.3. Switches and Buttons
The following illustrates the switches and buttons of the EVB.
J102
S402
S401
Figure 5: LG77L EVB Switches and Buttons

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Table 4: LG77L Switches and Buttons
3.4. Operation Status Indication LEDs
The indication LEDs on the EVB are shown as below.
D401D402
Figure 6: Operation Status Indication LEDs
Table 5: Operation Status Indication LEDs
Part No.
Name
I/O
Description
S201
POWER Switch
PI
Control power supply connect and disconnect
S401
RESET button
DI
Press and then release the button, the module
will be reset.
S402
FORCE_ON button
DI
Press and then release the button, the module
will be waked up from back up mode.
Part
Name
I/O
Description
D401
1PPS
DO
Flash: successful fix. The frequency is 1 Hz.
Extinct: no fix.
D402
TXD
DO
Flash: the module is turned on successfully, and
either Micro-USB or SD card interface can be used to
output messages.
Extinct or keep light: failed to turn on the module.

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3.5. Test Points
The following illustrates the test points of the EVB.
1
2
3
4
5
6
7
8
9
10
Figure 7: LG77L EVB Test Points - J106
Table 6: Pin Description of J106
Pin No.
Signal
I/O
Description
1
TXD
DO
Transmit data
2
RXD
DI
Receive data
3
RESET
DI
System reset
4
FORCE_ON
DI
System force on
5
ANT_DET
DI
Active antenna open circuit detection
6/7
GND
-
System ground
8
1PPS
DO
1 pulse per second
9
ANT_OK
DI
Active antenna short circuit detection
10
ANT_OFF
DO
Active antenna power control

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4EVB and Accessories Assembly
The following figure shows the assembly of LG77L EVB and its accessories.
Figure 8: LG77L EVB and Accessories Assembly

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5EVB Operation Procedures
This chapter mainly illustrates the operation procedures of LG77L EVB.
5.1. Communication via USB Interface
Step 1: Connect the EVB and the PC with a USB cable through USB interface, and then switch S201 to
ON state to power on the EVB.
Step 2: Run the USB flash drive on PC to install the USB driver. The USB port numbers can be viewed
through the PC Device Manager, shown as below.
Figure 9: USB Ports
Step 3: Install and then use the QCOM tool provided by Quectel to realize the communication between
the LG77L module and the PC.
The following figure shows the COM Port Setting interface of QCOM: select the correct “COM
Port”(USB Port shown in the above figure) and set the correct “Baudrate”(the default value:
9600 bps). For more details of QCOM usage, see document [1].
Figure 10: COM Port Setting Interface of QCOM

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5.2. Firmware Upgrade
Quectel LG77L module upgrades firmware via USB interface by default. Please follow the procedures
below to upgrade the firmware.
Step 1: Install and open the firmware upgrade tool (Firebird Update FW Tool) on PC.
Step 2: Power on the EVB according to the procedures mentioned in step 1 of Chapter 5.1.
Step 3: Follow the steps below to start firmware upgrade.
a) Select the COM port.
b) Choose the firmware package.
c) Click the “Baud rate” dropdown list and select the “9600”.
d) Click the “START” button to upgrade the firmware.
a
b
c
d
Figure 11:Firebird Update FW Tool Configurations for Firmware Upgrade

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6Usage of PowerGPS
6.1. PowerGPS Interface
6.1.1. COM Port and Baud Rate Setting
The PowerGPS tool can help you view the status of GNSS receiver conveniently.
After EVB accessories are assembled, turn on the module and start up the PowerGPS. After the tool is
opened, the following interface will be shown:
Figure 12: PowerGPS main Interface (no connection)
After that, select a correct COM port and baud rate (LG77L module supports 9600 bps by default), then
click the button （“Create Connection”）“OK”.

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Figure 13: COM Port and Baud Rate Selection PowerGPS main Interface (connect)
6.1.2. Explanations of PowerGPS Interface
From the PowerGPS interface, users can view CNR message, time, position, speed, precision, and so on.
Explanations are listed in the table below.
Table 7: Explanations of PowerGPS Interface
Icon
Explanation
⚫SV with PRN 65.If the position of SV is near to the centre of
the Sky View, the elevation angle of SV is close to 90°.
⚫Blue means this satellite is in tracking.
⚫Pale blue means this satellite is not in tracking.
⚫The CNR of SV with PRN is 49 dB/Hz.
⚫G represents GPS satellite, B represents BeiDou satellite, S
represents SBAS satellite.
⚫Pale-blue column means the navigation data of the satellite is
in use.