Fast serial data streams overcome link limitations

In many image-processing systems, large amounts of image data must be transferred rapidly between cameras and host CPUs. However, the system dependency on transmission protocols and operating systems of today's data communication methods can add significant overhead to data transmission rates. To overcome these limitations, Inova Semiconductor (Cotuit, MA) has developed a high-speed, point-to-point communications link, called GigaStar, that can transfer data up to 2.64 Gbit/s over standard twisted-pair cable at distances of 30 m. Consisting of the INGT165B transmitter and INGR165B receiver, the link converts a 33-MHz, 36-bit-wide data bus into a high-speed serial data stream.

Giga-Star data-link from Inova Semiconductors converts a 33-MHz, 36-bit-wide data bus into a 2.64-Gbits/s high-speed serial interface.

To interface digital 33-MHz data with a 2.64-Gbit/s high-speed interface, Inova designed both receiver and transmitter as a hybrid, separating the digital interface and the transmission layer. For the digital interface, the company partnered with Chartered Semiconductor (Singapore) to build a CMOS interface that can be buffered with FIFOs to adapt to any parallel interface. For the transmitter, Inova charged Austria Micro Systems International (Graz, Austria) with the task of integrating the phase-locked loops and voltage-controlled oscillators onto a bipolar ECL device. Once completed, the two dies were packaged by Amkor (Manila, Philippines) into hybrid receivers and transmitters.

To facilitate the GigaStar design, Inova is making the devices available with a chipset, a piggyback module, and a plug-and-play application kit. The piggyback module delivers the functionality of a full-duplex serial link at 2.64 Gbits/s and comprises transmitter and receiver ICs with a few external components. In operation, the piggyback board's transmitter converts parallel data of up to 36 bits into a serial bit stream. The receiver then converts the serial bit stream back to the original parallel data format, fully transparently with no protocol overhead.

To evaluate the two devices, Inova's application kit allows designers to build a 2.64-Gbit/s link in less than ten minutes. Including the piggyback module, software, loopback plug, cabling, and PC interface cable, this evaluation unit only requires a PC for control and a 3.3V power supply.

Already, sister company Inova Computers (Cotuit, MA) has used the Giga-Star as the I/O of choice for the precise control and synchronization of six-axle industrial robots. In the setup, two CompactPCI boards were connected through CPCI-GigaStar interfaces over distances between 3 and 15 m. According to Robert Kraus, general manager of Inova Semiconductors, the less than 1-µs latency time between the two systems demanded a high-speed synchronized interface with the minimum CPU loading of the GigaStar interface.