AVR-CDC is an USB-RS232C interface using CDC (Communication Device Class) protocol on USB 1.1. Although CDC is a part of USB 2.0 standard, it works on low speed USB with slower speed. ATtiny45 can handle the 4800bps 8N1 well enough.No dedicated driver necessary. CDC loads Windows built-in usbser.sys.It is very low cost ith ATtiny45, this is the cheapest solution for the USB-RS232C interface.[read]

To simplify this process of connecting the real world to the virtual, the CUI provides the necessary electronics to capture sensor input or control actuator output. The CUI comes with a USB port, a power LED, a Reset switch, a Programming switch, and a prototyping area. At the heart of the board is the PIC18F4550, a versatile microcontroller made by Microchip Technologies, Inc. The PIC18F4550 features thirteen A/D inputs, eighteen general I/O ports, and an efficient RISC-like instruction set. The CUI only uses one of the PIC’s general I/O ports; the remaining ports are available for user applications to be built in the prototyping area. The total cost of the CUI is around $30 US when built in small quantities. [read]

Features:MCU: PIC18F2550 with external xtal,ADC: one channel 0-2.5V sigma-delta converter, Linear Technology LTC2400/LTC2420, 6-channal 10-bit ADC 0-5V, Display: Two connectors for text LCD or GLCD, USB: onchip USB port with type B connector, Power supply: onboard low dropout regulator, rechargeable battery, Code programming: 10-pin header for In Circuit Loader.[read]