Serial Port Complete - Latest Microcontroller projects

Using Special-function USB Controllers

The chip can obtain its power from the VBUS line in the USB cable or from an

external supply that connects to the VCC pin. The 3V3OUT pin is a +3.3V

output. VCCIO is an input whose voltage determines the logic levels on the

UART and CBUS pins. The pin can connect to VCC, 3V3OUT, or an external

supply. The chip doesn’t require an external oscillator.

To convert the asynchronous serial interface to RS-232, use a Maxim MAX232

or similar interface chip. To convert to RS-485, use an SN75176B or similar

RS-485 transceiver.

Figure 15-1: The FT232R converts between USB and asynchronous serial data.