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Preview. The card is real — REV A1, and the pinout on this page is the card's own data, checked pin by pin. It is not in the catalogue yet, so the price is still a placeholder.
DIY KIT own board · REV A1

FORTY PINS. NO GUESSING.

A slotted card that drops over the Pi's 40-pin header and stays there while you wire. Every pin named and numbered where your hands already are — not on a browser tab behind you.

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GPIO CARD REV A1 — front and back. ENIG gold on cream mask.
40 Pins, both sides numbered
3 Pi 4 · Pi 5 · Pi 400
7 Function colours
3.3 V Logic — not 5 V tolerant
// The numbers

Specification

 7 rows

Fit

Fits Raspberry Pi 4, Pi 5 and Pi 400 — the standard 40-pin header
Mounting Slotted so it drops over the header and sits flat on the board

Print

Front All 40 pins, numbered both sides, colour-coded by function
Back I²C, SPI0, UART and PWM assignments, limits, reserved pins, QR to diykit.ae
Logic note Printed on the card: 3.3 V logic only — not 5 V tolerant

Build

Finish ENIG gold on cream mask, gold-plated eyelet
Revision GPIO CARD REV A1 · 2026-08
// Every header, pin by pin

Pinout

 4 pins

Filter to one header, or search for the pin you are looking for.

ODD Left column — odd pins

PinNameFunctionNote
1 3V3 3V3
3 GPIO2 SDA I²C
5 GPIO3 SCL I²C
7 GPIO4 GPIO
9 GND GND
11 GPIO17 GPIO
13 GPIO27 GPIO
15 GPIO22 GPIO
17 3V3 3V3
19 GPIO10 MOSI SPI
21 GPIO9 MISO SPI
23 GPIO11 SCLK SPI
25 GND GND
27 ID_SD Reserved HAT EEPROM — leave alone
29 GPIO5 GPIO
31 GPIO6 GPIO
33 GPIO13 PWM PWM
35 GPIO19 PWM PWM
37 GPIO26 GPIO
39 GND GND

EVEN Right column — even pins

PinNameFunctionNote
2 5V 5V
4 5V 5V
6 GND GND
8 GPIO14 TXD UART
10 GPIO15 RXD UART
12 GPIO18 PWM PWM
14 GND GND
16 GPIO23 GPIO
18 GPIO24 GPIO
20 GND GND
22 GPIO25 GPIO
24 GPIO8 CE0 SPI
26 GPIO7 CE1 SPI
28 ID_SC Reserved HAT EEPROM — leave alone
30 GND GND
32 GPIO12 PWM PWM
34 GND GND
36 GPIO16 GPIO
38 GPIO20 GPIO
40 GPIO21 GPIO
// What is on the back

The four buses, at a glance
I²C bus 1

SDA = GPIO2 · pin 3 · SCL = GPIO3 · pin 5

SPI0

MOSI = GPIO10 · MISO = GPIO9 · SCLK = GPIO11 · CE0 = GPIO8 · CE1 = GPIO7

UART

TXD = GPIO14 · pin 8 · RXD = GPIO15 · pin 10

Hardware PWM

GPIO12, 13, 18, 19 — Pi 4: 2 channels · Pi 5: 4 channels

Reserved

Pins 27 / 28 — HAT EEPROM (ID_SD / ID_SC). Greyed out on the card.

// The line that saves a Pi

Not 5 V tolerant

It is printed on the front where you will see it before wiring, not buried in a manual.

Logic Every GPIO is 3.3 V. A 5 V sensor output wired straight to a GPIO can damage the SoC.
Pins 2, 4 5 V rails — supply only. Never a signal level.
Pins 27, 28 Reserved for HAT identification. Use them as ordinary GPIO and HAT auto-detection breaks.
// Before you ask

Questions

 4 questions
Does it fit the Pi 5?
Yes — Pi 4, Pi 5 and Pi 400 all use the same 40-pin header and the same pin assignments, which is why one card covers all three.
Does it stay on while a HAT is fitted?
No. It slots over the header so it sits flat while you are wiring; a HAT wants the same pins, so the card comes off first.
Why does it say not 5 V tolerant?
Because it is the mistake that kills a Pi. Every GPIO is 3.3 V logic — a 5 V sensor output wired straight to a GPIO can damage the SoC. It is printed on the front where you will see it before wiring, not buried in a manual.
What are pins 27 and 28 for?
ID_SD and ID_SC, reserved for HAT identification EEPROM. Use them as ordinary GPIO and you break HAT auto-detection, so the card marks them greyed out.
// Register interest

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