Embedded World: Glasgow USB firm develops 16bit MCU

Fabless chip firm FTDI has introduced a second generation of USB controller, adding an on-die Harvard architecture microcontroller and peripherals including eight channels of PWM for motor control.

Dubbed Vinculum VNC2, it is a programmable dual USB chip in which the channels can independently operate as host or slave. It includes 256kbyte flash and 16kbyte of SRAM.

“Customers had two main issues with the first Vinculum [VNC1L], cost and flexibility. By designing our own 16bit microcontroller we have removed the requirement for an external MPU which means less cost,” said a company spokesman. “For flexibility, the hardware now comes in six different packages, and there is a C-based design environment, including our own RTOS.”

The MCU is specifically for the USB chip and included are four DMA controllers to shift data around the device, serial interfaces including UART and SPI, the PWM channels, and a programmable block that map on-chip resources to physical package pins.

Packages are both LQFP and QFN in 32, 8 and 64 lead forms.

The 48 pin LQFP variant is backward compatible with the original Vinculum, except for one power supply pin. “If the circuit board was deigned to the data sheet, they can drop in a zero Ohm resistor,” said the spokesman.

1.5Mb/s (low speed) and 12Mb/s (full speed) transactions are supported but, to keep power consumption down, 480Mb/s (high speed) is not.

The tool chain is free to customers, and also royalty free. “The individual tool blocks can be used with other design environments including Eclipse,” said the spokesman.

Object files provided support USB host functionality including USB flash drive storage, HID, USB COMMs class and FAT file functionality.

Will FTDI sell the new chips for general-purpose use?

“The device itself is USB-centric. A lot of the silicon is USB host/slave port,” said the spokesman.

Operating from +3.3V, stand-by is typically 128uA, and there are three low power modes.

Applications are expected in cameras, mobile accessories, data loggers, toys, keyboards, game controller interfacing, point-of-sale applications and USB to USB bridges.

Engineering samples of VNC2 are now available with mass production expected from May 2010.

For 10,000, the VNC2 48-pin LQFP is priced at $2.75 each.


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