USB to SPI/I²C bridge chip from FTDI; IO-rich and power-efficient

September 25, 2014 // By Graham Prophet
FTDI Chip’s FT4222H is the latest addition to its USB offering; cCompliant with the USB 2.0 hi-speed standard, this is a feature-rich single chip bridging solution with I²C and multi-channel SPI interface capabilities: It has support for multiple data lines and a variety of different configurations in order to maximise design flexibility

For SPI the device serves as a SPI Master/Slave interface controller and supports all four SPI modes (0, 1, 2, 3). It allows single, dual and quad data width transfer, so that total data rates of up to 27 Mbit/sec are possible. The integrated configurable I²C Master/Slave interface controller conforms completely with both I²C v2.1 and v3.0 specifications. Support is given for operation in 100 kbit/sec standard mode (SM), 400 kbit/sec fast mode (FM), 1 Mbit/sec fast mode plus (FM+) and 3.4 Mbit/sec high speed mode (HS). Configurable general purpose IOs (GPIOs) can be controlled by software applications via the USB bus. The USB 2.0 interface draws very little current either when it is active (75 mA typical) or while in suspend mode (375 µA typical).

As with other FTDI Chip USB device controllers, the USB protocol is fully taken care of by the IC itself, so that such activities do not waste valuable resources on the system microcontroller, which could lead to performance compromises being witnessed. The FT4222H's integrated OTP memory allows the storage of USB vendor ID (VID), product ID (PID), device serial number and product description string information, along with various other items of vendor specific data. The battery charger detection function furnishes USB peripherals that incorporate this IC with the ability to detect connection with a dedicated charging port (DCP) and thereby benefit from more rapid charging. FTDI Chip’s, royalty-free USB drivers for the Windows operating system mean that engineers can, in the majority of circumstances, avoid the inconvenience having to develop their own drivers.

The FT4222H comes in a compact, 32-pin QFN package with an operational temperature range that spans -40°C to 85°C for use in demanding industrial environments. It is priced at £1.54 (1000).

FTDI Chip;