Mini Ultra

Description

An updated version of our classic Mini Ultra 8 MHz. Powered by the newer ATmega4808 from the new megaAVR 0-series that comes with more program flash memory (48 kB), more RAM (6 kB) and 3 UART. We could have just stop at swapping out the MCU and call it a day but we wanted to put in as much features based on the years of feedback we received from our customers. For example, we know many people wanted to use different battery chemistry especially those lower than the 3.3V voltage rail like CR123A, LiFeFO4 or even 2xAA. 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-AU
  • Program flash memory: 48 kB
  • RAM: 6 kB
• Clock:
  • Internal 8/16 MHz oscillator
  • 32.768 kHz external crystal for real time counter (RTC) that still runs during sleep
• Operating voltage: 3.3 V / 5.0 V
• Low quiescent current (0.3 μA) on-board 3.3 V 300 mA buck-boost switching regulator
• Ultra low power: Minimum 4.0 μA in power down mode with input at 3.6V and VCC = 3.3V
• 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 A6
• Analog reference voltage with LC filter
• 600 mil in between 2 breakout headers – suitable for breadboard usage
• Dimension: 17.780 mm x 39.053 mm (0.700″ x 1.537″)
• FR-4 4-layer PCB with ENIG surface finish
• RoHS compliant: Yes!
• Note: Not completely pin compatible with Mini Ultra 8 MHz

Documentation:

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