budgetcan-fw CAN Bus Card
The budgetcan-fw CAN Bus Card is a community-designed 2x CAN bus expansion card based on the STM32F405 microcontroller and the budgetcan-fw platform1. Created by mowoe, it provides two independent CAN interfaces in the Framework expansion card form factor, distinct from the existing Cananka CAN-bus card which uses a PIC18F25K80 and MCP2221A bridge2.
Design
The card uses an STM32F405 as the CPU, running a forked and adapted version of the budgetcan-fw firmware1. The firmware fork for this specific board was planned to follow, but the README notes it is straightforward to adapt budgetcan-fw to the STM32F4051.
The expansion card features a 9-pin Würth Elektronik D-Sub connector with a pinout similar to the common Vector VN1610 dongles1. This means the connector stands out from the laptop rather than sitting flush — a deliberate trade-off to allow use without carrying a separate cable1. The USB connector is a MOLEX 1054440001 that sandwiches the PCB1.
A 3D-printable case was planned1. The repository includes Altium Designer schematic and PCB files (USB2CAN.SchDoc, can_transceiver.SchDoc, main.PcbDoc) along with a exported schematics.pdf1.
Specifications
| Specification | Details |
|---|---|
| MCU | STM32F4051 |
| CAN channels | 2x CAN1 |
| Firmware | budgetcan-fw (forked)1 |
| Connector | 9-pin Würth Elektronik D-Sub (VN1610-compatible pinout)1 |
| USB connector | MOLEX 10544400011 |
| Form factor | Connector stands out (not flush)1 |
| Design tool | Altium Designer1 |
| Source | mowoe/framework-can-expansion (GitHub)1 |
Related Projects
| Project | Description |
|---|---|
| CAN-bus Expansion Card (Cananka) | Earlier CAN bus card using PIC18F25K80 + MCP2221A |
| RS-232 Expansion Card | Medved's RS-232 serial expansion card |
| RS-485 Expansion Card | Medved's RS-485 serial expansion card |