FT12 USB Controller Series from FTDI Optimise Designers’ Implementation Choice

The FT12 series is configurable as a standard device class, and as such there is no need to add USB drivers. It was designed specifically so that engineers can quickly understand the device functionality and architecture, as well as taking advantage of application software and standard class drivers currently available and installed within the market.

“With the FT12 series offering, FTDI is widening the choice for engineers’ USB implementations,” states Dave Sroka, Global Product Director at FTDI. “These ICs enable the native class drivers of an operating system to be used, while providing flexibility on the device side to optimise implementations for a broad spectrum of applications. FTDI continues to strive to achieve its goal of ‘USB Made Easy’, by architecting the devices in a familiar fashion and at the same time providing high quality support through development tools, application notes and worldwide one-on-one technical assistance.”

Composed of three members, and inspired by the industry standard D12, the FT12 series offers unique features, like battery charging detection, numerous interface options and optimised device footprints - allowing the designer to choose the best-fit chip. A serial interface engine built into each FT12 handles the USB protocol, as well as carrying out packet recognition, checking and sequencing. Multiple USB transfer modes are supported, enabling bulk and isochronous data transfer activity, as well as supporting interrupt protocol.

For the FT120 and FT122 ICs, microcontroller/FPGA connection takes the form of an 8-bit generic parallel interface, while the FT121 supports SPI Slave mode. The FT120 has 3 USB endpoints, with 320 Bytes of configurable endpoint buffer integrated into the controller. The FT121 and FT122 offerings have greater capacity, with up to 8 bi-directional endpoints available and 2 kBytes of endpoint buffer capacity. Both the FT121 and FT122 also have USB battery charger detection functionality - allowing extra power from a dedicated charging port to be utilised, so that up to 1.8 A of current, rather than the usual 500 mA, can be drawn, without the need to add multiple external components into the circuit. Input voltages of 5 V or 3.3 V are supported, for all devices. The FT121 and FT122 handle all clock generation internally and require no crystal, thus freeing valuable PCB area and lowering system cost. A dedicated clock output pin with programmable clock frequency (from 4 MHz to 24 MHz) is also included.

The FT120 and FT122 are both supplied in TSSOP-28 and QFN-28 packages, while the FT121 is offered in TSSOP-16 and QFN-16 package options. All of these advanced USB controller ICs have an operating temperature range of -40 °C to 85 °C.

Development tool support is provided through 4 evaluation modules - the UMFT12XEV, UMFT120DC, UMFT121DC, and UMFT122DC - that can be used to implement and demonstrate USB functionality. The ‘DC’ denotes daughter-card functionality which enables the USB connection through a micro-B port and can be used in conjunction with the UMFT12XEV board or another microcontroller development system. The feature-rich UMFT12XEV board includes the LPC1114 microcontroller (preloaded with CDC class driver support), prototyping area, numerous connectors (SPI, JTAG, GPIO), LEDs for signal status and battery charging detection.