Many sensor chips use the I²C bus, sometimes called TWI or SMBus, for communication. Most microcontrollers support I²C also natively and if not I can be implemented easily in software. Connecting I²C devices to a PC is much more difficult as soldering them onto the mainboard (where a SMBus can be found usually) is not a viable solution. Up to now I usually used a Atmel AVR microcontroller in teamwork with a FT232R (a standard USB↔RS232 converter).

The USB 2.0 successor of the FT232R, the FT232H, has a Multi-Protocol Synchronous Serial Engine (MPSSE) included which is designed to support serial interfaces such as I²C, SPI or JTAG at speeds up to 30 Mbps. This sounded to me as an interesting option to test I²C and SPI devices directly from my PC. Continue reading →