STM32 Triple-Port Controller PCB

I need a compact controller board built around the STM32F103CBT6 in the 48-pin LQFP package (or a pin-compatible alternative with the same Cortex-M3 core). The board must expose three independent serial channels:

• RS-485
• RS-232
• A UART linked to an on-board serial-to-TCP module that speaks plain TCP/IP

Reliability is critical. Please integrate proven over-voltage, short-circuit and over-current protection on all power inputs as well as the three interface blocks.

If you are more comfortable substituting a different F1-series part with identical footprints, that’s fine as long as the firmware and pinout remain drop-in compatible.

Deliverables
• Complete schematic (Altium, KiCad or EasyEDA)
• Four/two -layer PCB layout with proper isolation between high-speed and power domains
• Gerber, drill files, pick-and-place and fabrication notes
• Clean BOM with supplier part numbers
• Minimal bootloader-level firmware showing the three ports working (echo test on RS-485/RS-232, socket connect test on TCP/IP)
• Short design report explaining the protection topology and component choices

I will review the design in two quick iterations, then have the board fabricated and powered up on my side. Release of final payment hinges on the board enumerating over SWD, passing the echo tests and drawing current within calculated limits.

If this fits your skillset in STM32 hardware, serial comms, and robust power design, let’s get rolling.