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SparkFun Board Pinout Reference

Explore SparkFun development board pinouts with this free SparkFun Board Pinout Reference. Identify GPIO layouts, power pins, UART, SPI, I2C, PWM, ADC pins, and connector configurations.

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  • Atmega328P Standard Uno Form
    RedBoard Qwiic Pinout
    REDBOARD QWIIC - ATMEGA328P UNO CORE D0 / RX D1 / TX D3 (PWM) D13 (SCK) SDA (I2C) SCL (I2C) A0 (Analog IN) A1 (Analog IN) A4 (SDA) A5 (SCL) GND (Common) VIN (7-15V Input)
    DIAGRAM: REDBOARD UNO PIN DISTRIBUTION

    Uno Format Header Configuration

    Pin Name Class Bus / Alternative Function Analog / ADC Ref Description & Operation Bounds
    D0Digital I/ORX / GPIO-Hardware Serial Receiver Port / Debug Input
    D1Digital I/OTX / GPIO-Hardware Serial Transmitter Port / Debug Output
    D2Digital I/OGPIO-General Digital Pin (External Interrupt 0)
    D3Digital I/OPWM / GPIO-Hardware Pulse Width Modulation (External Interrupt 1)
    D4Digital I/OGPIO-General Digital Pin
    D5Digital I/OPWM / GPIO-Hardware Pulse Width Modulation Output
    D6Digital I/OPWM / GPIO-Hardware Pulse Width Modulation Output
    D7Digital I/OGPIO-General Digital Pin
    D8Digital I/OGPIO-General Digital Pin
    D9Digital I/OPWM / GPIO-Hardware Pulse Width Modulation Output
    D10Digital I/OPWM / SPI_CS-Hardware PWM / SPI Chip Select Line
    D11Digital I/OPWM / SPI_MOSI-Hardware PWM / SPI Master Out Slave In Line
    D12Digital I/OSPI_MISO-SPI Master In Slave Out Line
    D13Digital I/OSPI_SCK (LED)-SPI Clock / On-board status Blue LED driver
    A0Analog InputGPIOADC0Analog Input Channel 0 (0 to 5.0V limit)
    A1Analog InputGPIOADC1Analog Input Channel 1 (0 to 5.0V limit)
    A2Analog InputGPIOADC2Analog Input Channel 2 (0 to 5.0V limit)
    A3Analog InputGPIOADC3Analog Input Channel 3 (0 to 5.0V limit)
    A4Analog InputI2C_SDA / GPIOADC4I2C Data Bus (Shares Atmega328P hardware engine)
    A5Analog InputI2C_SCL / GPIOADC5I2C Clock Bus (Shares Atmega328P hardware engine)
  • Ambiq Apollo3 Cortex-M4F Uno
    RedBoard Artemis Pinout
    REDBOARD ARTEMIS - CORTEX-M4F CORE D0 / RX (AP3_TX) D1 / TX (AP3_RX) Qwiic I2C (SDA/SCL) 3.3V Logic Rail
    DIAGRAM: ARTEMIS 3.3V UNO INTERFACES

    Artemis Uno Form Pinout (3.3V Logic Limit)

    Uno Pin Apollo3 GPIO Pin Standard Function Alternative Mappings & Interface Blocks
    D0PAD 25RX1 / GPIOUART1 Receiver / General Digital Pin
    D1PAD 24TX1 / GPIOUART1 Transmitter / General Digital Pin
    D2PAD 13GPIOInterrupt-capable general I/O
    D3PAD 11PWM / GPIOHardware PWM out / General Digital Pin
    D4PAD 29GPIOGeneral Digital Pin
    D5PAD 12PWM / GPIOHardware PWM out / General Digital Pin
    D6PAD 28PWM / GPIOHardware PWM out / General Digital Pin
    D7PAD 16GPIOGeneral Digital Pin
    D8PAD 17GPIOGeneral Digital Pin
    D9PAD 18PWM / GPIOHardware PWM out / General Digital Pin
    D10PAD 27PWM / SPI_CSSPI Chip Select / Hardware PWM Output
    D11PAD 22PWM / SPI_MOSISPI MOSI (I/O) / Hardware PWM Output
    D12PAD 23SPI_MISOSPI MISO Input
    D13PAD 21SPI_SCK (LED)SPI Clock Bus / Status LED driver pin
    A0PAD 15Analog InputADC channel 1 (3.3V Max threshold)
    A1PAD 14Analog InputADC channel 2 (3.3V Max threshold)
    A2PAD 35Analog InputADC channel 3 (3.3V Max threshold)
    A3PAD 34Analog InputADC channel 4 (3.3V Max threshold)
    A4PAD 33Analog InputADC channel 5 / Secondary I2C SDA Line
    A5PAD 32Analog InputADC channel 6 / Secondary I2C SCL Line
  • Artemis Compact Micro Board
    RedBoard Artemis Nano Pinout
    ARTEMIS NANO - COMPACT LAYOUT PAD 13 (A0) PAD 25 (RX) PAD 24 (TX) 3.3V Power Out PAD 32 (SDA) PAD 33 (SCL)
    DIAGRAM: NANO COMPACT PIN CONFIGURATION

    Artemis Nano Pad Map Table

    Nano Pin Apollo3 Pad Ref Bus / Logic Alternate Mappings Analog / ADC capability Hardware Descriptions
    A0PAD 13GPIOADC Channel 1Analog Input 0 / Digital I/O
    A1PAD 16GPIOADC Channel 2Analog Input 1 / Digital I/O
    A2PAD 33I2C1_SCL / GPIOADC Channel 3I2C1 Clock Bus / Analog Input 2
    A3PAD 11PWM0 / GPIOADC Channel 4Pulse Width Modulation / Analog Input 3
    D3PAD 40GPIO-General Digital Pin
    D4PAD 39SPI_SCK / GPIO-SPI Serial Clock Bus Line
    D5PAD 35SPI_MISO / GPIO-SPI Master In Slave Out Line
    D6PAD 12SPI_MOSI / PWM1-SPI Master Out Slave In / PWM Output
    TXPAD 24TX0 / UART0-UART0 Main Serial Transmitter Output
    RXPAD 25RX0 / UART0-UART0 Main Serial Receiver Input
    SDAPAD 32I2C1_SDA / GPIO-I2C1 Data Bus Line
    SCLPAD 33I2C1_SCL / GPIO-I2C1 Clock Bus Line (Shared with Pin A2)
  • 48-GPIO Artemis Mega Board
    RedBoard Artemis ATP Pinout
    REDBOARD ARTEMIS ATP - 48-GPIO MEGA EXPANSION
    DIAGRAM: ATP ALL-PIN EXPANSION BLOCKS

    Artemis ATP Key Pin Definition Table

    ATP Pin Label Apollo3 Pad Ref Bus Type Primary Configuration & Native Features
    Pin 0PAD 25UART1_RXUART1 Serial Receiver In
    Pin 1PAD 24UART1_TXUART1 Serial Transmitter Out
    Pin 2PAD 35I2C3_SDAI2C Bus 3 Data Link
    Pin 3PAD 34I2C3_SCLI2C Bus 3 Clock Link
    Pin 4PAD 39SPI0_MISOSPI0 Master In Slave Out
    Pin 5PAD 38SPI0_MOSISPI0 Master Out Slave In
    Pin 6PAD 23SPI0_SCKSPI0 Clock Bus Line
    Pin 7PAD 22SPI0_CSSPI0 Chip Select 0 Line
    Pin 12PAD 12PWM_CH1Hardware PWM Output channel 1
    Pin 13PAD 13PWM_CH2Hardware PWM Output channel 2
    Pin A0PAD 16ADC0Analog Input Channel 0 (3.3V Max limit)
    Pin A1PAD 29ADC1Analog Input Channel 1 (3.3V Max limit)
    Pin A2PAD 11ADC2Analog Input Channel 2 (3.3V Max limit)
    Pin A3PAD 31ADC3Analog Input Channel 3 (3.3V Max limit)
    Pin A4PAD 32ADC4Analog Input Channel 4 (3.3V Max limit)
    Pin A5PAD 15ADC5Analog Input Channel 5 (3.3V Max limit)
  • Artemis Feather Form Factor
    SparkFun Thing Plus - Artemis Pinout
    THING PLUS - ARTEMIS FEATHER MAP LEFT PIN COLUMN (ADC / Power) RIGHT PIN COLUMN (UART / SPI / I2C)
    DIAGRAM: THING PLUS (FEATHER) HARDWARE PORTS

    Thing Plus (Feather Profile) Pinout Table

    Thing Plus Label Apollo3 Pad Ref Primary Function Bus / Alternative Mapping Description & Operation Bounds
    3V3-Power OutputRegulated 3.3V Source800mA max onboard regulator output
    RSTPAD 18Reset InputSystem control resetActive-Low Hardware Reset
    GND-Power GroundCommon Ground ReferenceCommon system ground return
    A0PAD 16Analog InputADC Channel 0Analog Input Channel 0 (3.3V Max limit)
    A1PAD 29Analog InputADC Channel 1Analog Input Channel 1 (3.3V Max limit)
    A2PAD 11Analog InputADC Channel 2Analog Input Channel 2 (3.3V Max limit)
    A3PAD 31Analog InputADC Channel 3Analog Input Channel 3 (3.3V Max limit)
    A4PAD 32Analog InputADC Channel 4Analog Input Channel 4 (3.3V Max limit)
    A5PAD 15Analog InputADC Channel 5Analog Input Channel 5 (3.3V Max limit)
    SDAPAD 33Digital I/OI2C1 SDAMain hardware I2C Data line
    SCLPAD 32Digital I/OI2C1 SCLMain hardware I2C Clock line
    MOSIPAD 38Digital I/OSPI_MOSISPI Master Out Slave In line
    MISOPAD 39Digital I/OSPI_MISOSPI Master In Slave Out line
    SCKPAD 23Digital I/OSPI_SCKSPI Serial Clock Bus Line
    TXPAD 24Digital I/OUART0_TXHardware Serial Port Transmit Output
    RXPAD 25Digital I/OUART0_RXHardware Serial Port Receive Input

Input Parameters Specification

SBC Quick FilterLocate individual board layouts using the top dynamic search utility.
Qwiic Connect ArchitectureSparkFun Qwiic ports utilize a standard 4-pin JST connector carrying GND, 3.3V, SDA, and SCL lines.
Artemis Pad logicAmbiq Apollo3 microcontrollers operate strictly on a 3.3V logic rail. Standard pins are not 5V tolerant.
ATP Multi-Port AccessThe ATP board breaks out the full 48-GPIO footprint of the Apollo3 module into a high-density, Mega-style form factor.

Practical Operational Examples

Configuring Serial Console on Artemis

Target pins TX1 (PAD 24) and RX1 (PAD 25) with a 3.3V USB-to-UART converter to establish serial terminal debug consoles safely.

Adding I2C Qwiic Sensors

Chain multiple Qwiic sensors using standard pre-wired cables to easily connect I2C displays and accelerometers.

Controlling PWM Channels

Drive motors or adjust LED brightness by mapping output lines to hardware-backed PWM-capable pads (e.g., D3 or D5).

Artemis Deep Sleep Code

Trigger ultra-low power modes in software, bringing current draw down to microamps while keeping RTC wakeup counters active.

Logic and Power Rail Theory

SparkFun RedBoard and Thing Plus platforms utilize advanced ARM Cortex and RISC-V SoC architectures. Because these modern silicon chips feature sub-micron processes, they rely on clean, stabilized 3.3V CMOS logic signaling. Applying direct 5V input lines to these delicate ports will compromise internal chip junctions and lead to complete processor failure.

Tip: Always trace and secure your common ground (GND) connections first to protect high-frequency SPI and I2C lines from static discharge.

Formulas & Mathematical Logic

Series Current Limiting: R_series = (3.3V - V_led) / I_target (Keep below 4-8mA per pin)
I2C Pull-Up Range: R_min = (3.3V - V_low) / I_sink, preventing overcurrent drain on open-drain pins.
Analog Resolution Calculation: V_step = 3.3V / 4096 steps (Based on Apollo3 native 12-bit ADC architecture)

About This Reference Guide

Quick access to standard SparkFun development board layouts.

This reference consolidates layout configurations, logic states, and physical system interfaces across the SparkFun family.

Finding accurate pinout layouts is crucial for embedded designers, system architects, IoT engineers, and DIY hobbyists. This directory documents active signal paths to help prevent wiring errors, serial protocol failures, and board damage.

Always verify pinout configurations with a digital multimeter before powering up custom circuits or shield adapters.

Supported BoardsRedBoard Qwiic, Artemis, Artemis Nano, Artemis ATP, and Thing Plus modules.
Hardware SafeguardsClear warnings regarding 3.3V logic thresholds and analog voltage boundaries.
Protocol MapsDirect pin definitions for SPI, UART, I2C, DAC, and active RF lines.
Qwiic EcosystemExplains standard JST SMT port configurations for easy modular prototyping.

Frequently Asked Questions

1. Are SparkFun Artemis GPIO pins 5V tolerant?

No, the logic pins operate strictly at a 3.3V threshold. Exposing any GPIO, SPI, or UART pins to a 5V logic source without a level shifter can cause immediate hardware failure.

2. What is the default baud rate of the serial console?

By default, SparkFun development boards configure their main UART debug terminal (TXD0 / RXD0) to a baud rate of 115200.

3. Can I power the RedBoard directly using the 5V pins?

Yes, you can apply regulated 5.0V directly to the 5V power header pins. However, this bypasses the on-board input protection fuse, so ensure your power source is regulated and stable.

4. Why do some SPI and I2C channels fail when a sensor is chained?

Adding too many devices to a single I2C bus can exceed the safe capacitive load limit, degrading signal integrity. Use lower-value pull-up resistors or active bus extenders for long chains.

5. How do I reset search filters in this tool?

Clear any text from the search box at the top of the interface to restore the full list of pinout cards.

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SparkFun Board Pinout Reference is a free online calculator tool. Use it to get instant, accurate results for your electronics calculations.