HK32F030M - Chinese ARM for 15 cents

Final board

Quote:

Basic BOM:

CH340E
HK32F030MF4P6
SX3M32.000M20F30TNN
TYPE-C-31-M-12
ME6211A33PG-N
1N5819WT
HS91L02W2C01
XL-3216RGBC
CTS-3425J-V-TR

Rest are common parts easily sourced anywhere, 0402 resistors / capacitors, pin headers, 25xx/24xx memories...

Edit: Fix PCB
- Missing GND trace for CH340E.
- CH340E RTS/DTR not working as expected, remove them.