FTDI.FT-X series USB to serial bridges can be still reasonable option even for today.
Microcontrollers with USB interface are common nowadays. Manufacturers provide source codes for USB device classes like CDC, HID, Mass storage and DFU. . Even in this case, programming USB communications may not be a trivial task. If it is only required to replace RS232 serial interface to USB, is worth considering using of FTDI TF-X series USB to serial bridge.Advantages:
- Entire USB protocol handled on the chip. No USB specific firmware programming required.
- Detection of connection to DCP (Dedicated Charging Port) USB port.
- Lower requirements for microcontroller resources. Communication through UART, I2C or SPI is less resource demanding than implementation of USB CDC device class
- Drivers for Windows, Mac OS-X, Linux and Android for free.
- Microcontroller pins are connected to USB connector through USB/serial bridge. ESD or overvoltage spikes on USB bus can damage bridge instead of microcontroller. Replacement of small bridge chip is simpler than replacement of microcontroller.
Disadvantages:
- USB/serial bridge chip requires PCB space and increases cost.
Microcontrollers with USB interface are common, but… – [Link]
