OpenT2OTP
About the OpenT2OTP PCB
OpenT2OTP is an open source Microchip SAM PCB design by token2, published on GitHub under the MIT license. It is a 2-layer board measuring 48 × 24 mm, with 15 components from 13 distinct parts.
Its main chip is the ATSAML22N18A, from the Microchip SAM family. Other key parts include the NFC front-end (back side) and Secure element (back side). By type, the board carries 5 capacitors, 3 ICs, 2 resistors, 1 crystal, 1 connector and 1 battery holder.
From the project
open-source programmable TOTP hardware token
This directory holds a connectivity schematic for the openT2OTP reference board, generated from the documented design. It is not a routed PCB — it gives you the correct components and nets so you can drop in real footprints and lay out the board.
placement.png is a suggested component-placement diagram. It shows where each part would sit on a 48×24 mm board that fits the OT1 enclosure, with the arrangement matched to the real reference board (battery clip at one end, IC cluster at the other, LCD and button on the front).
Main components on the OpenT2OTP
OpenT2OTP bill of materials (BOM)
15 components, 13 distinct parts — part numbers from the project's BOM.
| Qty | Part | Footprint | Refs |
|---|---|---|---|
| 1 | ATSAML22N18A MCU (QFN) (back side) | qfn48 | U1 |
| 1 | NFC front-end (back side) | qfn32 | U2 |
| 1 | Secure element (back side) | son8 | U3 |
| 1 | 32.768kHz (back side) | xtal_can | Y1 |
| 1 | prog pads (back side) | swd | J1 |
| 1 | CR2025/2032 clip (back side) | bat_clip | BT1 |
| 1 | 6-digit LCD (COG) | lcd | DS1 |
| 1 | Power/show | sw_th | SW1 |
| 2 | tune C0G (back side) | c0805 | C1, C2 |
| 1 | LCD bias (back side) | c0805 | C3 |
| 1 | 100nF (back side) | c0603 | C7 |
| 1 | 1uF (back side) | c0603 | C9 |
| 2 | 10k (back side) | c0603 | R1, R2 |
OpenT2OTP design files
The KiCad project lives in the token2/openT2OTP repository on GitHub; these links point at the commit this page was built from.
OpenT2OTP: common questions
What microcontroller does the OpenT2OTP use?
The OpenT2OTP is built around the ATSAML22N18A, from the Microchip SAM family.
How big is the OpenT2OTP PCB?
The OpenT2OTP measures 48 × 24 mm, has 2 copper layers and is 1.6 mm thick.
How many components are on the OpenT2OTP?
15 components, from 13 distinct parts, with part numbers taken from the project's own BOM. The full bill of materials is listed on this page.
Where can I download the OpenT2OTP design files?
From the token2/openT2OTP repository on GitHub, which has the KiCad layout, the schematic and the BOM; the links under Design files point to each one.
Can I use the OpenT2OTP design in my own project?
Yes, under the terms of its MIT license, which token2 chose for the repository.
Can I test firmware for the OpenT2OTP without the hardware?
Yes. HardLabs builds a simulation of the board from its netlist and BOM, so you can run and debug Microchip SAM firmware against it before you order a PCB.
Similar boards
Microchip SAMFpgaboy
Wren6991
50 × 50 mm89 parts4LNo license508
Microchip SAMKira
kiibohd
366.9 × 114.3 mm400 partsCERN-OHL-1.2415
Microchip SAMDSKY driver
benkrasnow
43 × 92.3 mm44 partsMIT258
Microchip SAMDuet 2 Maestro
Duet3D
100 × 123 mm336 partsCERN-OHL-1.2257
Microchip SAMMainboard
pycubed
90.2 × 95.9 mm196 parts2LNo license96
Microchip SAMTiny4FSK
New-England-Weather-Balloon-Society
35.1 × 76.3 mm80 parts4LCERN-OHL-W-2.095