CAN-bus Expansion Card (Cananka)

The CAN-bus Expansion Card (Cananka) is a community-designed expansion card adding a CAN bus interface to any Framework laptop¹². Created by Josip Medved (medo64) and first prototyped in March 2022, it uses a PIC18F25K80 microcontroller and an MCP2221A USB-to-UART bridge, supporting SLCAN and SocketCAN¹²³.

Design

The card is based on Medved's existing Cananka USB-to-CAN adapter, shrunk to fit the expansion card form factor¹. It uses a PIC18F25K80 MCU with an integrated CAN controller and an MCP2221A for USB-to-UART conversion¹. The external connector is a 4-pin vertical JST PH header with GND, CAN L, CAN H, and V+ (not connected)²³.

The card uses a full-size PCB (flush with the frame) and a 3D-printed case¹. Two LEDs indicate UART communication and CAN bus activity². Bus termination is software-controlled¹.

The expansion card variant is non-isolated; an isolated full-size version exists in the main Cananka repository³.

Pinout

4-pin JST XH connector (pin 1 on the left, looking into the card)²:

Pin	Signal
1	GND
2	CAN L
3	CAN H
4	V+ (not connected)

Specifications

Specification	Details
MCU	PIC18F25K80 (integrated CAN controller)1
USB bridge	Microchip MCP2221A1
Bus speed	Up to 1 Mbit/s (125 kbit/s default)23
Interface	SLCAN (serial), SocketCAN (Linux)23
Serial speed	Up to 460,800 baud3
Isolation	Non-isolated (expansion card variant)3
Termination	Software-controlled1
Connector	4-pin JST PH (vertical)12
Indicators	2 LEDs (UART activity, CAN activity)2
PCB thickness	0.8 mm1
Source	Medo64/CanankaFEC (GitHub)3
License	MIT3

Related Projects

Project	Description
RS-232 Expansion Card	Medved's RS-232 serial card using MCP2221 + MAX232
RS-485 Expansion Card	Medved's RS-485 half-duplex card using FT232RL

Footnotes

1. Cananka for Framework Laptop — Medo's Home Page (Josip Medved, March 2022) ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹

2. Cananka Framework Expansion Card — Medo's Home Page ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹

3. Medo64/CanankaFEC — GitHub (MIT) ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹