AC07 LoRa Mary

Features

Send and receive messages or sensor data over LoRa radio when combined with an MCU (microcontroller) leaf. Prepare a compatible device at the other end of the link for low-power wireless communication.

This LoRa leaf uses a Murata Type ABZ module and a chip antenna (STAF 1019-085A) with Japanese radio equipment construction design certification. It comes programmed with firmware v1.2.3, published for the Arduino MKR WAN 1300/1310, so you can program it with Arduino.

Specifications

Item	Description
Part number	CMWX1ZZABZ-091
Chipset	SX1276, STM32L072CZ
Secure element	ATECC608A
Carrier frequency	920MHz band (920.6 MHz to 928 MHz), Japan
Modulation method	LoRa™ modulation
Antenna	Murata antenna support (Japanese)
Interface	SPI
RF certification	FCC, IC, TELEC, KCC
Dimensions	W23 × D30 × H2mm

LoRaWAN and private LoRa

LoRaWAN and private LoRa both use LoRa modulation for wireless communication, but their upper MAC layers differ. LoRaWAN is a standard developed by the LoRa Alliance that supports interoperability between devices from different manufacturers and wide-area communication. Private LoRa uses a proprietary MAC-layer protocol and requires a dedicated gateway, with no communication fees. See the following references for more information.

• Differences between LoRaWAN and private LoRa (Japanese)
• The Arduino Guide to LoRa® and LoRaWAN®

Board layout

The Molex 73412-0110 is compatible with the U.FL RF coaxial connector developed by Hirose Electric.

Antennas

LoRa Mary has a chip antenna (1019-085A) with Japanese radio equipment construction design certification. For longer-range communication, attach an external antenna.¹ The antennas below have this certification. See Murata antenna support (Japanese) for details.

Model	Supplier	Antenna type	Connector	Dimensions	Note
1019-085A2	STAF Corporation	Monopole (λ/4)		4 × 9.1 × 1.2mm	Chip antenna
1018-504B2	STAF Corporation	Dipole (λ/2)	U.FL	100 × 13 mm (cable length 140mm)	FPC antenna
1019-008A	STAF Corporation	Monopole (λ/2)	SMA3	Length 160mm, diameter 9mm	External antenna

Pin assignment

See the Leafony pin assignment documents for the source data.

Libraries

• LoRa.h
• TCA9536.h
• SparkFun_ATECCX08a_Arduino_Library.h

For details, see Installing Libraries.

Sample applications

These samples use the STM32 MCU and LoRa Mary leaves. Include the LoRaLeafony.h library when using them.

• LoRa message communication (Japanese)
• LoRa sensor data communication (Japanese)

Documents

• Schematic
• Component mounting drawing

Tips

Programming firmware with STLINK and STM32CubeProgrammer

1. Prepare the following:
   • LoRa Mary, Shield and screws
   • A 3.3V power supply, or USB for power
   • STLINK-V3SET
   • A computer and USB cable
2. Secure LoRa Mary and USB (for power) to the Shield with screws, then connect the STLINK-V3SET. See Connecting the debugger for details.
3. Start STM32CubeProgrammer.
4. Select ST-Link as the connection on the right, set Frequency(KHz) to 8000, and click Connect.
5. Open the erase and programming panel on the left and configure the following:
   • File path: select the v1.2.3 .bin file.
   • Enable programming verification.
6. Click Start Programming. Programming is complete when Download verified successfully appears.

Programming firmware with FP-10 and C-Flash

1. Prepare the following:
   • LoRa Mary, Shield and screws
   • A 3.3V power supply, or USB for power
   • computex FP-10
   • A computer and USB cable
2. Download C-Flash:
   • Enter the CODE and SERIAL NO printed on the FP-10 at the C-Flash download page, then download the software.⁴
3. Load the program into the FP-10:
   • Connect the FP-10 to the computer and start C-Flash.
   • Click 設定 (Settings) → ターゲット設定 (Target settings).
   • Select the manufacturer to narrow down the microcontroller list, choose the STM32L07xxZ filter, and click 起動する (Start).
   • On the initial settings tab, set the target to 未接続 (Not connected), and select SWD and 1MHz for the interface.
   • Click ファイル (File) → ロード (Load) → 追加 (Add), then select the v1.2.3 .bin file.
   • Set the load address to 0x08000000, which is the Flash start address.
   • Select データ (Data) → 書き込み (Write) to load the program into the FP-10.
4. Program LoRa Mary:
   • Connect the FP-10 to a USB AC adapter.
   • Secure LoRa Mary and USB to the Shield with screws, then connect to an AC adapter.
   • Connect the FP-10 to the Shield’s SWD interface.
   • Press the FP-10 PROGRAM button. The STS LED lights when programming succeeds.

Spreading factor (SF) and bandwidth (BW)

SF describes how much the transmitted data is spread. The LoRa library accepts values from 6 to 12, with SF7 as the default. SF6 requires implicit header mode for both transmission and reception. See the LoRa library API for details. The main characteristics are shown below.

SF	Characteristics
SF6–SF8	Shorter communication range and higher data rate
SF10–SF12	Longer communication range and lower data rate

BW is the width of the frequency band. Common values are 125kHz, 250kHz and 500kHz, with 125kHz as the default. The main characteristics are shown below.

Bandwidth	Characteristics
Narrow (125kHz)	Lower data rate, longer communication range and lower power consumption
Wide (500kHz)	Higher data rate, shorter communication range and higher power consumption

Footnotes

1. The chip antenna and external antenna cannot be used together. To use an external antenna, reposition the 0Ω resistor. ↩

2. These antennas are certified even though they are not included in Murata’s recommended antenna list. ↩ ↩²

3. SMA stands for SUB-MINIATURE TYPE A and is a MIL-standard connector. Use a U.FL-to-SMA adapter cable to connect it to LoRa Mary. ↩

4. See the setup video (Japanese) for download and licensing instructions. ↩