Mini Ultra LoRa

Description

We added SX1276 LoRa transceiver and EUI-64 identification chip to our Mini Ultra so you could run LoRaWAN stack such as the LMIC library with plenty of program flash memory and RAM left for your application code. The board is powered by the MegaCoreX Arduino core which is written and maintained by MCUdude. On top of that, we added an updated Arduino compatible low power library that can be used together with a simple Real Time Counter (RTC) library also written by us to allow flexible low power management of the board (or any MCU in the AVRmega 0-series).

Specifications:

• Compatible with Arduino IDE using MegaCoreX Arduino core
• Microcontroller: ATmega4808-MU
  • Program flash memory: 48 kB
  • RAM: 6 kB
  • Data EEPROM: 256 Bytes
  • 3 UART
• Clock:
  • Internal 8 MHz oscillator
  • 32.768 kHz external crystal for accurate real time counter (RTC) that still runs during sleep
• Operating voltage: 3.3 V
• EByte E19-900M20S2 SX1276 LoRa transceiver:
  • With solder jumper to connect DIO1, DIO2 and RESET to use LoRaWAN stack by running library such as the LMIC stack
  • Tested with Jan Gromeš’ RadioLib library for pure LoRa usage
• 2Kb I2C Serial EEPROM with Pre-Programmed EUI-64™ MAC ID 24AA025E64T:
  • Unique 64-bit identification to be used as DevEUI in LoRaWAN network
  • Can be used as small storage logging
• Low quiescent current (0.3 μA) on-board 3.3 V 300 mA buck-boost switching regulator
• Ultra low power: Minimum 5.0 μA in power down mode with input at 3.6V
• External DC source range: 1.8 – 5.5 V
  • Auto power switching between power source applied on the VBAT pin on breakout pin or VIN pin on the FTDI 6-pin header
  • Option to use various battery type, cell combination and chemistry such as 2xAA or 3xAA (alkaline, NiMH), CR123A, LiFeFO4, Li-Ion/Pol
• Red indicator LED connected to digital pin 7
• FTDI 6-pin header with additional UPDI interface:
  • Upload code either through serial or burn code directly using UPDI programmer like our jtag2updi based UPDI-USB-Serial Adapter board
• Battery power monitoring on pin A5
• Analog reference voltage with LC filter
• Easy access side tactile reset switch
• No on-board charger
• 4 M2 mounting holes
• 800 mil in between 2 breakout headers – suitable for breadboard usage
• Dimension: 22.86 mm x 44.45 mm (0.90″ x 1.75″)
• FR-4 4-layer PCB with ENIG surface finish
• RoHS compliant: Yes!

Documentation:

• Schematic
• Design files on Github
• LMIC OTAA sleep example
• Arduino compatible low power library
• Arduino compatible simple Real Time Counter (RTC) library