I want to share the basic things I learnt today about PCBs.

UART (universal asynchronous receiver-transmitter): is a computer hardware device for asynchronous serial communication in which the data format and transmission speeds are configurable. The UART interface consists of two pins: the Rx and Tx pin. The Rx pin is used to receive data. The Tx pin is used to transmit data. When two devices are connected using a UART, the Rx pin of one device is connected to the Tx pin of the second device.

UPDI Programmer (Unified Program and Debug Interface): is an interface for external programming and on-chip debugging of microcontrollers. On there boards, Tx and Rx are combined with a 4.7k resistor at the same pin.

Microcontroller board: is a microcontroller built onto a printed circuit board. This board provides all of the circuitry necessary for a useful control task: a microprocessor, I/O circuits, a clock generator, RAM, stored program memory and any necessary support ICs.

Microcontroller: is a small computer on a single VLSI integrated circuit (IC) chip. A microcontroller contains one or more CPUs (processor cores) along with memory and programmable input/output peripherals.

Boards