# Adafruit QT Py RP2040

> Adafruit QT Py RP2040: dual Cortex-M0+ at ~125 MHz, 264 KB RAM, 8 MB QSPI flash, 13 GPIO (4 ADC) at 3.3 V on castellated XIAO-footprint pads, USB-C, STEMMA QT I2C port, NeoPixel, 17.8 × 20.8 mm.

- Manufacturer: Adafruit Industries
- Part number: 4900
- Category: Development boards
- Canonical page: https://www.xirkit.io/products/adafruit-qt-py-rp2040-bdcf
- Pinout: https://www.xirkit.io/products/adafruit-qt-py-rp2040-bdcf/pinout
- Structured JSON: https://www.xirkit.io/products/adafruit-qt-py-rp2040-bdcf/data.json
- Source: Xirkit structured parts catalog — every value traced to a cited document; unknowns are explicit.

## Key specifications

| Property | Value |
| --- | --- |
| Main chip | RP2040 |
| Chips on board | RP2040 |
| Exposed GPIO | 13 |
| Documented board pins | 16 |
| I/O voltage | 3.3 V |
| Supply voltage | 5–5 V |
| Flash | 8,192 KB |
| SRAM | 264 KB |
| Interfaces | adc, spi, i2c, pwm, uart, gpio, pio, usb, other, clock |
| Frameworks | CircuitPython, MicroPython, Arduino |
| Dimensions | 20.83 × 17.78 mm |

## Pinout (16 pins, 13 with electrical limits)

| Pin | Position | Kind | Chip pad | Functions | VIH | VIL | VOH | VOL | IOH | IOL | 5 V tolerant |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| A0/D0 | JP1 · JP1-1 | gpio | GPIO29 | ADC3, SPI1 CS, I2C0 SCL, PWM6 B, SPI1_CSn, UART0_RX, SIO, PIO0, PIO1, USB_VBUS_EN | 2–3.6 V | -0.3–0.8 V | 2.62–3.3 V | 0–0.5 V | ≤ 12 mA | ≤ 12 mA | no |
| A1/D1 | JP1 · JP1-2 | gpio | GPIO28 | ADC2, SPI1 MISO, I2C1 SDA, PWM6 A, SPI1_RX, UART0_TX, I2C0_SDA, SIO, PIO0, PIO1, USB_VBUS_DET | 2–3.6 V | -0.3–0.8 V | 2.62–3.3 V | 0–0.5 V | ≤ 12 mA | ≤ 12 mA | no |
| A2/D2 | JP1 · JP1-3 | gpio | GPIO27 | ADC1, SPI1 MOSI, I2C1 SCL, PWM5 B, SPI1_TX, UART1_RTS, SIO, PIO0, PIO1, USB_OVCUR_DET | 2–3.6 V | -0.3–0.8 V | 2.62–3.3 V | 0–0.5 V | ≤ 12 mA | ≤ 12 mA | no |
| A3/D3 | JP1 · JP1-4 | gpio | GPIO26 | ADC0, SPI1 SCK, I2C1 SDA, PWM5 A, UART1_CTS, SIO, PIO0, PIO1, USB_VBUS_EN | 2–3.6 V | -0.3–0.8 V | 2.62–3.3 V | 0–0.5 V | ≤ 12 mA | ≤ 12 mA | no |
| SDA/D4 | JP1 · JP1-5 | gpio | GPIO24 | I2C0 SDA, digital I/O pin 4, UART1 TX, PWM4 A, SPI1_RX, SIO, PIO0, PIO1, CLOCK_GPOUT2, USB_OVCUR_DET | 2–3.6 V | -0.3–0.8 V | 2.62–3.3 V | 0–0.5 V | ≤ 12 mA | ≤ 12 mA | no |
| SCL/D5 | JP1 · JP1-6 | gpio | GPIO25 | I2C0 SCL, digital I/O pin 5, UART1 RX, PWM4 B, SPI1_CSn, SIO, PIO0, PIO1, CLOCK_GPOUT3, USB_VBUS_DET | 2–3.6 V | -0.3–0.8 V | 2.62–3.3 V | 0–0.5 V | ≤ 12 mA | ≤ 12 mA | no |
| TX/D6 | JP1 · JP1-7 | gpio | GPIO20 | UART1 TX, I2C0 SDA, PWM2 A, SPI0_RX, SIO, PIO0, PIO1, CLOCK_GPIN0, USB_VBUS_EN | 2–3.6 V | -0.3–0.8 V | 2.62–3.3 V | 0–0.5 V | ≤ 12 mA | ≤ 12 mA | no |
| RX/D7 | JP3 · JP3-1 | gpio | GPIO5 | UART1 RX, SPI0 CS, I2C0 SCL, PWM2 B, SPI0_CSn, SIO, PIO0, PIO1, USB_VBUS_EN | 2–3.6 V | -0.3–0.8 V | 2.62–3.3 V | 0–0.5 V | ≤ 12 mA | ≤ 12 mA | no |
| SCK/D8 | JP3 · JP3-2 | gpio | GPIO6 | SPI0 SCK, digital I/O pin 8, I2C1 SDA, PWM3 A, UART1_CTS, SIO, PIO0, PIO1, USB_OVCUR_DET | 2–3.6 V | -0.3–0.8 V | 2.62–3.3 V | 0–0.5 V | ≤ 12 mA | ≤ 12 mA | no |
| MI/D9 | JP3 · JP3-3 | gpio | GPIO4 | SPI0 MISO, digital I/O pin 9, UART1 TX, I2C0 SDA, PWM2 A, SPI0_RX, SIO, PIO0, PIO1, USB_VBUS_DET | 2–3.6 V | -0.3–0.8 V | 2.62–3.3 V | 0–0.5 V | ≤ 12 mA | ≤ 12 mA | no |
| MO/D10 | JP3 · JP3-4 | gpio | GPIO3 | SPI0 MOSI, digital I/O pin 10, I2C1 SCL, PWM1 B, SPI0_TX, UART0_RTS, SIO, PIO0, PIO1, USB_OVCUR_DET | 2–3.6 V | -0.3–0.8 V | 2.62–3.3 V | 0–0.5 V | ≤ 12 mA | ≤ 12 mA | no |
| SDA1 | STEMMA QT · STEMMA QT | gpio | GPIO22 | I2C1 SDA for the STEMMA QT connector, SPI0 SCK, PWM3 A, UART1_CTS, I2C1_SDA, SIO, PIO0, PIO1, CLOCK_GPIN1, USB_VBUS_DET | 2–3.6 V | -0.3–0.8 V | 2.62–3.3 V | 0–0.5 V | ≤ 12 mA | ≤ 12 mA | no |
| SCL1 | STEMMA QT · STEMMA QT | gpio | GPIO23 | I2C1 SCL for the STEMMA QT connector, SPI0 MOSI, PWM3 B, SPI0_TX, UART1_RTS, I2C1_SCL, SIO, PIO0, PIO1, CLOCK_GPOUT1, USB_VBUS_EN | 2–3.6 V | -0.3–0.8 V | 2.62–3.3 V | 0–0.5 V | ≤ 12 mA | ≤ 12 mA | no |
| 3V | JP3 · JP3-5 | power out | — | power_out | — | — | — | — | — | — | — |
| GND | JP3 · JP3-6 | ground | — | ground | — | — | — | — | — | — | — |
| 5V | JP3 · JP3-7 | power in | — | power_in | — | — | — | — | — | — | — |

## Where to buy

| Supplier | Price | Stock | Checked | URL |
| --- | --- | --- | --- | --- |
| www.adafruit.com | 9.95 USD | in_stock | 2026-09-25 | https://www.adafruit.com/product/4900 |

## FAQ

**What microcontroller does the Adafruit QT Py RP2040 use?**

The Adafruit QT Py RP2040 is built around the RP2040, alongside AP2112K-3.3, WS2812B.

**How many GPIO pins does the Adafruit QT Py RP2040 have?**

13 GPIO pins are exposed. Xirkit documents 16 board pins, 13 of them with pin-level electrical limits.

**Are the Adafruit QT Py RP2040 I/O pins 5 V tolerant?**

No. The I/O pins are not 5 V tolerant — they run at 3.3 V logic; use a level shifter for 5 V signals. Input-high threshold: 2–3.6 V.

**How much current can a Adafruit QT Py RP2040 GPIO pin source?**

Documented output-high current per pin: ≤ 12 mA. Values are traced to the chip datasheet; see the pinout table for per-pin limits and conditions.

**What voltage powers the Adafruit QT Py RP2040?**

Supply range 5–5 V. Power inputs: 5V.

**How much does the Adafruit QT Py RP2040 cost?**

From $9.95 at www.adafruit.com. Prices are observed unit prices before tax and shipping.

**What are the Adafruit QT Py RP2040 dimensions?**

20.83 × 17.78 mm. A STEP model is available for enclosure fit checks.

**Which interfaces does the Adafruit QT Py RP2040 support?**

adc, spi, i2c, pwm, uart, gpio, pio, usb, other, clock.

**How do I program the Adafruit QT Py RP2040?**

Supported frameworks: CircuitPython, MicroPython, Arduino.

**Where does this Adafruit QT Py RP2040 data come from?**

Every value in this record is traced to a source — 2 documents including the board and chip datasheets — with the page and table cited per value. Unknowns are left explicit, never guessed.

## Sources

- [Adafruit QT Py RP2040 datasheet](https://cdn-learn.adafruit.com/downloads/pdf/adafruit-qt-py-2040.pdf)
- [www.adafruit.com listing](https://www.adafruit.com/product/4900)

## Part graph

### Built from

- [RP2040](https://www.xirkit.io/products/category/dev-boards/rp2040) — main processor on the Adafruit QT Py RP2040
- AP2112K-3.3 — voltage regulator on the Adafruit QT Py RP2040
- WS2812B — rgb led on the Adafruit QT Py RP2040

### Alternatives (by use case)

- [Raspberry Pi Pico W](https://www.xirkit.io/products/raspberry-pi-pico-w-8b30) — Both serve custom digital protocols and precise timing — check the trade-offs; $9.95 vs $6
- [Raspberry Pi Pico 2](https://www.xirkit.io/products/raspberry-pi-pico-2-1cde) — Both serve custom digital protocols and precise timing — check the trade-offs; $9.95 vs $5
- [Raspberry Pi Pico 2 W](https://www.xirkit.io/products/raspberry-pi-pico-2-w-b3bc) — Both serve custom digital protocols and precise timing — check the trade-offs; $9.95 vs $7
- [Adafruit Feather RP2040](https://www.xirkit.io/products/adafruit-feather-rp2040-802e) — Both serve custom digital protocols and precise timing — check the trade-offs; $9.95 vs $11.95
- [STM32 Nucleo-64 NUCLEO-F446RE (MB1136)](https://www.xirkit.io/products/stmicroelectronics-stm32-nucleo-64-nucleo-f446re-mb1136-2179) — Both serve custom usb devices (hid, midi, serial) — check the trade-offs; $9.95 vs $18.66
- [Arduino Nano ESP32](https://www.xirkit.io/products/arduino-nano-esp32-d5fc) — Both serve custom usb devices (hid, midi, serial) — check the trade-offs; $9.95 vs $19.3
- [Adafruit ESP32-S3 Feather (8 MB flash, no PSRAM)](https://www.xirkit.io/products/adafruit-esp32-s3-feather-8-mb-flash-no-psram-a873) — Both serve custom usb devices (hid, midi, serial) — check the trade-offs; $9.95 vs $17.5

### Pin-compatible

- [Seeed Studio XIAO RP2040](https://www.xirkit.io/products/seeed-studio-xiao-rp2040-53de) — Same Seeed XIAO footprint and pad layout (guide p10: 'Pinout and shape is Seeed Xiao compatible') and the same RP2040
- [Seeed Studio XIAO ESP32C3](https://www.xirkit.io/products/seeed-studio-xiao-esp32c3-99be) — Same Seeed XIAO footprint and pad layout (guide p10) — different main chip
- [Seeed Studio XIAO ESP32-S3](https://www.xirkit.io/products/seeed-studio-xiao-esp32-s3-f8f5) — Same Seeed XIAO footprint and pad layout (guide p10) — different main chip
- [Seeed Studio XIAO nRF52840 Sense](https://www.xirkit.io/products/seeed-studio-xiao-nrf52840-sense-a973) — Same Seeed XIAO footprint and pad layout (guide p10) — different main chip