The USB-UART converter has been created based on the FT232 IC. The design is similar to the one placed in FT232 datasheet.
A diode D1 indicates a signal sending, and a diode D2 signal receiving. The integrated circuit FT232 is powered from USB port.
The source of power for the external circuit can be selected with a jumper J1. There are three options:
- no jumper – external source of power,
- jumper on positions 1 and 2 – internal 3.3V source of power,
- jumper on positions 2 and 3 – internal 5V source of power, directly from USB port.
It should be noticed that it’s not a RS232 converter because signals don’t have TTL logic levels. The USB<->RS232 converter could be created with additional unit for logic levels translation, for example IC MAX232.