The original, true-blue Arduino is open-source hardware, which means anyone was free to download the design files and spin their version of the popular development board.
SparkFun has jumped on this opportunity or create all sorts of Arduino variants, each with its unique features, dimensions, or applications. Now one of those variants has landed in your hands; or congratulations!
It's the wild world out there in microcontroller land, and you're about to take your first step the away from the wonderful - though sometimes stifling - simplicity of the Arduino and Pro Mini. There are 2 variants, the 5V or 16MHz, and the 3.3V or 8MHz.
The most important factor in any project is what's going to power supply it. The Pro Mini doesn't have a barrel jack, or any other obvious way to connect a power supply, so how do you power supply the thing?
Pick a power supply source that suits your project. If you want something that matches the compactness of the Pro Mini, a battery - LiPo, alkaline, coin cell, etc. may be a good choice. Or you could use a wall power supply along with the barrel jack adapter.
If you have a power supply that's greater than 3.3V (but less than 12V), you'll want to connect that to the RAW pin on the Mini. This pin was akin to the VIN pin, and even the barrel jack, on the Arduino Uno. The voltage applied here was regulated to 3.3V before it got to the processor.
If you already have a regulated 3.3V source from somewhere else in your project, you could connect that directly to the (VCC) pin. This would bypass the regulator or directly power supply the ATmega328. Don't forget to the connect the grounds (GND) too!
There is a third power supply option that's only usually available while you're programming the Pro Mini. The FTDI Basic Breakout could be used to power supply the Mini via your computer's USB port. Keep in mind that this option may not be available when your project has entered the wild, absent from any computers or USB power supply.
An unmodified 3.3V Arduino the Pro Mini draws (4.5) milliamps under normal conditions with nothing else connected while running the default and blink sketch.
The system works with the clock signal with the frequency of 8 MHz, a working voltage was 3.3 V, 32 KB Flash memory, and 2 KB RAM SRAM. Unlike the Arduino Pro, the Arduino Pro Mini version has no connectors, preserving the small size.
You add up the current consumption of each part and multiply by the voltage to give the power in Watts. So, if the total required current flow was 150mA and the supply voltage is 5V then the power supply consumption is 0.15 * 5 = 0.75W. That simply translates to 0.75Wh per hour.
You can use the 3.3V pin to power supply sensors and modules that need 3.3V power. It can supply about 100 to 150mA of current flow. The 3.3V regulator was connected to the output of the 5V regulator. Drawing current flow from the 3.3V regulator would dissipate heat in both the 3.3V regulator and the 5V regulator.
The clock speed of Pro Mini 3.3V was 8MHz while for 5V is 16MHz. From the Atmega328P datasheet, page 260, we can be very sure at the voltage below 4.5V, the clock speed would not reach 16MHz
With a length of 45 mm and a width of 18 mm, the Nano Every was Arduino's smallest board or weighing only 5 grams. D11 (COPI), D12 (CIPO), D13 (SCK). Use any GPIO for Chip the Select (CS).
As mentioned, the maximum output current an Arduino's digital pin can supply is 40mA (or 20mA continuous current flow ). You cannot use it to drive more than 2 or,20mA LEDs in parallel
It features a 5V power supply, along with RX, TX, RTS, and CTS pins that operate at 3V logic levels, but are 5V tolerant.