Dragino LGT-92 LoRaWAN User manual

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LGT-92 LoRaWAN GPS Tracker User Manual
Document Version: 1.0
Image Version: v1.3
Version
Description
Date
1.0
Release
2018-Dec-12
1.0.1
Correct GPS payload format in TTN
2019-Jan-23

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1. Introduction..............................................................................................................................4
1.1 What is LGT-92 LoRa GPS Tracker ..............................................................................................4
1.2 Specifications..............................................................................................................................5
1.3 Features......................................................................................................................................6
1.4 Applications................................................................................................................................6
2. Use LGT-92 with stock LoRaWAN firmware ...............................................................................7
2.1 How it works?.............................................................................................................................7
2.2 Quick guide to connect to LoRaWAN server (OTAA) ...................................................................7
2.3 Uplink Payload..........................................................................................................................10
2.3.1 Payload Analyze ..............................................................................................................10
2.3.2 Add Payload format in TTN .............................................................................................10
2.4 Downlink Payload.....................................................................................................................12
2.5 Firmware Change Log...............................................................................................................12
3. Use AT Command....................................................................................................................13
3.1 Access AT Command.................................................................................................................13
3.2 Common AT Command Sequence.............................................................................................15
3.2.1 Multi-channel ABP mode (Use with SX1301/LG308) ......................................................15
3.2.2 Single-channel ABP mode (Use with LG01/LG02)...........................................................15
4. Upload Firmware .................................................................................................................... 16
5. Developer Guide .....................................................................................................................18
5.1 Source Code..............................................................................................................................18
5.2 Compile Source Code ................................................................................................................18
5.2.1 Set up Keil compile environment....................................................................................18
5.2.2 Install STM32L0 Series Device.........................................................................................21
5.2.3 Compile Source Code......................................................................................................22
6. FAQ .........................................................................................................................................23
6.1 Why there is 433/868/915 version? .........................................................................................23
6.2 What is the frequency range of LT LoRa part? .........................................................................24
6.3 How to change the LoRa Frequency Bands/Region? ................................................................25
6.4 Can I use Private LoRa protocol? ..............................................................................................25

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6.5 How to set up LGT-92 to work in 8 channel mode in US915, AU915, CN470 bands? ...............26
6.6 What is the pin mapping for the USB program cable? .............................................................26
6.7 How to set up LGT-92 to work with Single Channel Gateway such as LG01/LG02? .................27
7. Order Info ............................................................................................................................... 29
8. Packing Info ............................................................................................................................29
9. Support...................................................................................................................................29
10. Reference................................................................................................................................30

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1. Introduction
1.1 What is LGT-92 LoRa GPS Tracker
LGT-92 is a Long Range / low power consumption LoRaWAN GPS tracker. LGT-92 get user’s
location info via GPS and send it to IoT server via LoRaWAN wireless network.
Compare to traditional GPS tracker, LGT-92 use much lower power consumption hence can last
for longer time. It doesn’t need cellular service; system integrator can build their own tracking
network base on LoRa technology.
LGT-92 uses STM32l0x chip from ST, STML0x is the ultra-low-power STM32L072xx
microcontrollers incorporate the connectivity power of the universal serial bus (USB 2.0
crystal-less) with the high-performance ARM® Cortex®-M0+ 32-bit RISC core operating at a 32
MHz frequency, a memory protection unit (MPU), high-speed embedded memories (192 Kbytes
of Flash program memory, 6 Kbytes of data EEPROM and 20 Kbytes of RAM).
LGT-92 includes a low power GPS module L70 and 9-axis accelerometer for motion and attitude
detection. The power for both of the GPS module and accelerometer can be controlled by MCU
to achieve the best energy profile for different applications.
LGT-92 is powered by 1000mA Li-on battery, user can program the device to work from weeks to
months depends on the target use case.
LGT-92 is an open source product, it is based on the STM32Cube HAL drivers and lots of libraries
can be found in ST site for rapid development.

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1.2 Specifications
Micro Controller:
STM32L072CZT6 MCU
MCU: STM32L072CZT6
Flash:192KB
RAM:20KB
EEPROM: 6KB
Clock Speed: 32Mhz
Common DC Characteristics:
Supply Voltage: 2.1v ~ 3.6v
Operating Temperature: -40 ~ 85°C
LoRa Spec:
Frequency Range,
Band 1 (HF): 862 ~ 1020 Mhz
or
Band 2 (LF): 410 ~ 528 Mhz
168 dB maximum link budget.
+20 dBm - 100 mW constant RF output vs.
+14 dBm high efficiency PA.
Programmable bit rate up to 300 kbps.
High sensitivity: down to -148 dBm.
Bullet-proof front end: IIP3 = -12.5 dBm.
Excellent blocking immunity.
Low RX current of 10.3 mA, 200 nA register retention.
Fully integrated synthesizer with a resolution of 61 Hz.
FSK, GFSK, MSK, GMSK, LoRaTM and OOK modulation.
Built-in bit synchronizer for clock recovery.
Preamble detection.
127 dB Dynamic Range RSSI.
Automatic RF Sense and CAD with ultra-fast AFC.
Packet engine up to 256 bytes with CRC.
LoRaWAN 1.0.2 Specification
Battery:
1000mAh Li-on rechargeable battery
Power Consumption
Sleeping Mode: 77uA
LoRa Transmit Mode: 125mA @ 20dBm 44mA @ 14dBm

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Tracking: max: 38mA
1.3 Features
LoRaWAN 1.0.2 Class A,Class C
STM32L072CZT6 MCU
SX1276/78 Wireless Chip
Pre-load bootloader on USART1/USART2
MDK-ARM Version 5.24a IDE
Preamble detection
Frequency bands CN470/EU433/KR920/US915/IN865
EU868/AS923/AU915
Open source hardware / software
Regular/ Real-time GPS tracking
Built-in 9 axis accelerometer (MPU9250)
Motion sensing capability
Power Monitoring
Charging clip with USB port
1000mA Li-on Battery power
Tri-color LED, Alarm button
1.4 Applications
Smart Buildings & Home Automation
Logistics and Supply Chain Management
Significant Assets management.
Human tracking

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2. Use LGT-92 with stock LoRaWAN firmware
2.1 How it works?
The LGT-92 is pre-loaded with a firmware and is configured as LoRaWAN OTAA Class A mode by
default. It has OTAA keys to join LoRaWAN network. To connect a local LoRaWAN network, user
just need to input the OTAA keys in the LoRaWAN IoT server and power on the LGT-92. It will auto
join the network via OTAA.
In case user can’t set the OTAA keys in the LoRaWAN OTAA server and has to use the keys from
the server. User can use AT Command to set the keys in LGT-92.
2.2 Quick guide to connect to LoRaWAN server (OTAA)
Here is an example for how to join the TTN LoRaWAN Network. Below is the network structure,
we use LG308 as LoRaWAN gateway in this example.
The LG308 is already set to connect to TTN network . So what we need to now is only configure
the TTN:
Step 1: Create a device in TTN with the OTAA keys from LGT-92.
Each LGT-92 is shipped with a sticker with the default device EUI as below:

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User can enter this key in their LoRaWAN Server portal. Below is TTN screen shot:
Add APP EUI in the application
Add APP KEY and DEV EUI

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Step 2: Power on LGT-92 LoRaWAN GPS Tracker
Step 3: LGT-92 will auto join to the TTN network. After join success, LGT92 will start to upload
message to IoT server.
By default, the upload period is 5 minutes. In the start of each period, LGT-92 will try to get GPS
signal and the green LED will blink. Once LGT-92 get the GPS info, it will upload a LoRa message
include battery / GPS info/ X,Y axis info. If LGT-92 can’t get GPS info into 2 minutes, it will still
upload the message but the GPS info will be all 00.

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2.3 Uplink Payload
2.3.1 Payload Analyze
The uplink payload includes totally 12 bytes. Uplink packets use FPORT=2 and every 5 minutes
send one uplink by default.
Size(bytes)
3
3
2
2
2
Value
Latitude
Longitude
BAT
X
Y
Example:
Latitude: 06765f ⇒if (0x06765f & 0x800000 = 0 ): value = 0x06765f /10000 = 42.3519
Longitude: F2960a ⇒if (0xF2960a & 0x800000 = 1 ):
value = (0xf2960a –0x 1000000)/10000 -87.9094
BAT: Ex1: 0x0B45 ⇒3850mV
X: 04D2 = if (0x04D2 & 0x8000 = 0 ): value = 0x04D2 / 1000 = +1234 ⇒+1.234G
Y: FB2E =if (0xFB2E & 0x8000 = 1 ): value =( 0xFB2E - 0x10000)/1000(dec) ⇒ -1.234G
2.3.2 Add Payload format in TTN
In TTN, use can add a custom payload so it shows friendly.
In the page Applications --> Payload Formats --> Custom --> decoder
Add below code:
//The function is :
function Decoder(bytes, port) {
// Decode an uplink message from a buffer
// (array) of bytes to an object of fields.
var value=bytes[0]<<16 | bytes[1]<<8 | bytes[2];
if(bytes[0] & 0x80)