TouCAN Probe

A compact USB 2.0 to CAN/RS‑485/RS‑422 hardware probe for interfacing and debugging CAN networks and differential serial buses. Designed in KiCad 9. Firmware is here: https://github.com/AndersBNielsen/TouCAN_fw

Overview

• MCU: STM32F042C6Tx (USB FS device)
• CAN transceiver: SN65HVD230
• RS‑485/RS‑422 transceivers: SP3485EN (2x)
• USB‑C receptacle (HCTL HC‑TYPE‑C‑16P‑01A)
• 3.3V LDO regulator: MIC5504‑3.3
• Crystals: 8 MHz and 32.768 kHz
• CAN DE‑9 (female) connector for classic CAN pinout
• Jumpers/headers for boot, CAN, RS‑422/485 routing

Project metadata

• Title: TouCAN Probe
• Company: ABNielsen.com
• Revision: 0
• Board: 4‑layer FR4, ~1.6 mm

Repository Structure

• USB-TouCAN.kicad_sch — KiCad schematic
• USB-TouCAN.kicad_pcb — KiCad PCB layout
• USB-TouCAN.kicad_pro — KiCad project file
• USB-TouCAN.kicad_prl — KiCad project local settings
• DSUB-9_... .kicad_mod — Custom footprint for DE‑9 female connector
• production/ — Fabrication outputs
  • bom.csv — Bill of Materials (includes LCSC part numbers)
  • designators.csv — Designator map
  • positions.csv — Pick‑and‑place (component positions)
  • netlist.ipc — IPC‑D‑356 netlist
  • backups/ — Historical fabrication snapshots
• fabrication-toolkit-options.json — Fabrication/export options

Key BOM Highlights

From production/bom.csv:

• MCU: STM32F042C6Tx (LQFP‑48)
• CAN: SN65HVD230 (SOIC‑8)
• RS‑485/422: SP3485EN (SOIC‑8, 2x)
• USB‑C receptacle: HC‑TYPE‑C‑16P‑01A
• LDO: MIC5504‑3.3
• Crystals: 8 MHz (3225), 32.768 kHz (3215)
• LEDs: Green (D1), Red (D2)
• DE‑9 CAN connector and various pin headers/jumpers

Fabrication

• KiCad: generator version 9.0; board setup targets a 4‑layer FR4 stackup.
• Use KiCad’s Plot tool to generate Gerbers and drill files (settings are stored in the project). The IPC netlist in production/netlist.ipc can be provided to your manufacturer for electrical test.
• Pick‑and‑place: production/positions.csv.
• BOM: production/bom.csv contains LCSC part numbers to streamline sourcing; DNPs are excluded per fabrication-toolkit-options.json.

Assembly & Bring‑Up

• Power from USB‑C (VBUS) with on‑board 3.3 V regulation.
• Boot/Programming: STM32F042 can be programmed via USB DFU or SWD (boot header present). Firmware will be released separately.
• CAN I/O: DE‑9 (male) with CAN_H and CAN_L; USB‑C provides data connection to host.
• RS‑485/RS‑422: Routing and driver enable/receive enable pins exposed via headers/jumpers.

If JP4 is closed at reset, USB is CDC USART1 for RS422/485. If JP4 in open, USB is GS_USB CAN

Jumpers can be moved into any position after reset.

RS-422: Default Full duplex RS-422: Short JP3 & JP4

RS422/485 can be used in CAN mode using external USB-to-UART via USART1 pins (PB7 is RX and PB6 is TX)

Status

Hardware files are provided; software/firmware will be licensed and released later.

License

Hardware design files in this repository are licensed under the Creative Commons Attribution‑ShareAlike 4.0 International (CC BY‑SA 4.0). See LICENSE-Hardware.md for the full text.

Software/firmware (when added) will use a separate license.

Credits

• Author/Company: ABNielsen.com
• EDA: KiCad 9