USB to RS232 serial converter

This is a galvanically isolated USB to RS2332 serial adapter. The repository includes project files for both a PCB and an enclosure.

Short data:

• One USB-C connector and one DB25 D-SUB male connector
• Full ±12V voltage swing on the RS232 side
• Rx/Tx and RTS and CTS signals are available
• Galvanic isolation provided by the MAX22246
• USB to serial conversion handled by the CP2102
• Supported data formats:
  • Data bits: 5, 6, 7, and 8
  • Stop bits: 1, 1.5, and 2
  • Parity: Odd, even, mark, space and none
  • Baud rates from 300 to 921600
• Supports serial break

Tools used

This project was created using:

• KiCad 9.0 and kicad-jlcpcb-tools plugin for generating PCB and fabrication files
• FreeCAD 1.0.2 for 3D modeling the enclosure

Assembly Instructions

To ensure easy and successful assembly, follow these steps:

1. Mount all surface-mount components. All necessary files are included for ordering fully assembled PCBs (apart from through hole components) from JLCPCB.
2. Mount all through-hole components. This includes the 3mm green LED and the DC/DC converter.
3. Mount the D-SUB connector:
   • Place the PCB into the enclosure so the USB connector and LED aligned correctly.
   • Position the D-SUB connector and screw it in place using the #4-40 standoffs and solder it in place.
   • Disassemble the PCB and solder the other side of the D-SUB connector.
4. Final assembly
   • Reassemble the PCB in the enclosure.
   • Slide on the lid.
   • Secure the lid using 2 × M2.5 × 14mm countersunk machine screws.