Input Parameters Specification
Pin Muxing Capabilities
Details on port pins designed to share general-purpose input/output (GPIO), analog inputs, PWM, and communications.
Operating Voltage (3.3V vs 5V)
Voltage logic level constraints defining safety margins for high-level inputs to avoid destroying internal gates.
Primary Bus Interfaces
Dedicated line paths mapped to SPI (MISO/MOSI/SCK), I2C (SDA/SCL), and serial UART (TX/RX) standards.
Power Sourcing Schemes
Power routing configurations allocating load paths across USB, battery inputs (VBAT), and regulated pin rails.
Board Design & Serial Interfaces Theory
Development boards provide safe physical access to microcontrollers by routing raw silicon pins to standardized header layouts. These boards include voltage regulation, USB-to-serial conversion, and filtering components to protect the processor. High-speed serial interfaces (like SPI and I2C) are broken out alongside analog-to-digital converter (ADC) channels, allowing the board to communicate with sensors and peripherals without signal degradation.
Tip: Standard Arduino UNO and Nano boards run at 5V logic. Connecting them directly to 3.3V boards (such as Teensy 3.x/4.x or MKR series) without level shifters can damage the inputs.
About This Reference Guide
Your direct lookup path for Arduino, Teensy, and raw AVR development boards.
This reference index consolidates pin configurations, expansion header maps, and line assignments for the Arduino family, high-speed Teensy platforms, and raw ATmega/ATTiny microcontroller chips.
Navigating changing board configurations is critical for firmware developers, IoT engineers, and electronics makers. Pin-to-pin alignment is essential to prevent hardware damage from system voltage lines.
Always verify operating voltages (5V vs 3.3V) before constructing custom connections. Correct connection paths preserve performance and safety.
Arduino PlatformsClassic UNO, Mega, Nano, and modern ARM-based MKR/Zero architectures.
Teensy SeriesHigh-performance Teensy 2.0, 3.x, LC, and 4.x platforms.
AVR ComponentsRaw ATmega328, ATmega2560, and ATTiny microcontrollers.
Circuit ProtectionDetailed warnings regarding logic level compatibility between standard boards.
Frequently Asked Questions
1. What is the difference between Arduino UNO and Leonardo pinouts?
The UNO uses the ATmega328P with fixed hardware SPI/I2C pins. The Leonardo uses the ATmega32U4, which features native USB. This shifts the SPI pins to the ICSP header and changes the analog input pin locations.
2. Why do Teensy boards feature much higher pin densities?
Teensy boards use advanced ARM Cortex-M processors. These chips break out a larger number of hardware timers, PWM channels, multiple serial ports, and secondary SPI/I2C buses on a compact board area.
3. Can I program raw ATmega328 chips using the Arduino IDE?
Yes. By configuring an active Arduino board as an ISP (In-System Programmer), you can upload bootloaders and sketches directly to raw ATmega328 chips via their SPI and Reset pins.
4. What are the analog input limitations on MKR series boards?
MKR boards use the SAMD21 processor, which runs on 3.3V logic. Exceeding 3.3V on any analog input pin will damage the internal analog-to-digital converter.
5. How does the Teensy 4.0 manage 5V tolerance?
Teensy 4.0 is not 5V tolerant. All I/O pins run strictly on 3.3V logic. Connecting 5V signals to any digital or analog pin without a level shifter can damage the processor.
6. What is the purpose of the ICSP header on Arduino boards?
The In-Circuit Serial Programming (ICSP) header provides direct SPI bus access (MISO, MOSI, SCK, Reset, VCC, GND). This allows you to flash bootloaders or firmware directly to the main processor without using the USB-to-serial chip.