Microcontroller to USB Serial Interface Circuit

Microcontroller to USB Serial Interface Circuit

Figure 1. USB to MCU Serial Interface

An example of using the FT232R as a USB to Microcontroller(MCU) UART interface is shown in Figure 7.4. In this application the FT232R uses TXD and RXD for transmission and reception of data, and RTS# / CTS# signals for hardware handshaking. Also in this example CBUS0 has been configured as a 12MHz output to clock the MCU. Optionally, RI# could be connected to another I/O pin on the MCU and used to wake up the USB host controller from suspend mode. If the MCU is handling power management functions, then a CBUS pin can be configured as PWREN# and would also be connected to an I/O pin of the MCU.

FT245BM datasheet pdf


Implementation USB to microcontroller (AVR)
Purpose of this article is to inform readers about implementation USB interface into singlechip microcontroller, which this interface directly not supports. Simply: implementation USB interface on firmware level (similar as emulation of RS232 Serial interface in microcontrollers, which not have RS232 Serial support). This project includes development of firmware on microcontroller side, driver development on computer side (for Windows operating system) , development of DLL library for functions calling from another programs (programmers level) and development of demo program (users level), which shows all functions of this device. Device is named IgorPlug-USB (AVR) (as successor of my previous device for computer remote control IgorPlug - serial port version).

Universal USB interface
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