The most popular and versatile medium today for adding off-the-shelf or custom functionality to a system board is the PMC standard, a.k.a. PCI Mezzanine Card or, more formally, IEEE 1386.1. Most commonly fielded in a 2.9 x 5.9-inch format, PMC is available in a broad array of boards. Dozens of companies add graphics, communications, networking and other functions to a CPU or DSP system board. Complexity ranges from boards with a few serial ports to full-fledged processing boards that pack a microprocessor or DSP chip.
The benefits of PMC are clear-cut. For those making processing boards or dumb carrier boards, this technology makes it possible to sell a small number of general-purpose boards into a large number of applications by customizing them with PMC add-ons. For those making PMC boards themselves, the standard provides broad market appeal, supported as it is on VMEbus, Compact PCI and even the trailing-edge Multibus II.
On the user end, PMC gives developers the ability to create tailored subsystems that precisely meet their needs, whether it's for an extra Ethernet port to gain network redundancy, for an analog I/O capability to turn a DSP baseboard into a data-acquisition front end, or for a platform on which to implement custom applications that are tightly-coupled to the processing board.
Among the new serial PMC boards, Cyclone Microsystems Inc. (New Haven, Conn.), General Micro Systems (Rancho Cucamonga, Calif.) and SBS GreenSpring Modular I/O (Menlo Park, Calif.) have all unleashed four-channel entries. Synergy Microsystems Inc. (San Diego), meanwhile, has come to market with a PMC board that packs as many as 32 serial channels.
Cyclone's PMC 50 delivers quad RS-422 serial ports, simultaneously operating at up to 10 Mbits/second. Its eight DMA channels boast "high-performance DMA controllers for optimized data transfer to and from host memory," said company vice president Peter Zackin.
The controllers operate on linked lists, Zackin said, and "large on-chip FIFOs combined with enhanced threshold control mechanisms allow decoupling of traffic requirements on host bus and serial interfaces with little exception probabilities, such as data underruns and overflows." Another feature is programmable protocol processing. The board is $252 each in lots of 1,000. A VxWorks driver is optional.
The four serial channels on the PMC-HS Serial from SBS GreenSpring are also independently programmable, handling asynchronous protocols at up to 2 Mbits/s and synchronous protocols at up to 10 Mbits/s. Different physical interfaces-RS-232, RS-422, EIA-449 and so on-are also software-configurable. It's priced at $675. A VxWorks driver is optional.
The PMC QSIO from General Micro Systems likewise provides independence for its four serial channels in speed, protocol and operating mode. In synchronous mode, the channels max out at 20 Mbits/s; asynchronous mode provides sustained data rates of up to 154 kbits/s. "To maximize performance and better accommodate bursty traffic, each QSIO channel is also equipped with 32 bytes of FIFO buffering on both the receive and transmit channels," said Ben Sharfi, company president.
The OMC QSIO comes with drivers for VxWorks, Phar Lap and Windows NT 4.0. It's priced at $780 in 100-piece quantities.
As for Synergy, its PU32 PMC board adds 20 serial I/O ports to a VME baseboard or 32 ports for a VME board using a five-row DIN connector. Each port supports a bit rate of up to 128 kbits/s. Pricing starts at $800.
Several companies recently introduced PMC boards with analog and digital I/O for interfacing to the real world. General Standards Corp. (Huntsville, Ala.), for instance, has two entries: the $1,395 PMC-Opto32, with 32 optically coupled digital channels configured as 24 inputs and eight outputs; and the $2,975 PMC-ADADIO analog I/O board, which contains eight 16-bit inputs, sampled simultaneously at 60 Hz, as well as four analog outputs and an 8-bit bidirectional data port.
With real-world data capture for DSP systems in mind, Blue Wave Systems Inc. (Carrollton, Texas) offers a high-precision, multichannel analog I/O card for PMC with a complement of 16 20-bit analog-input channels, two 24-bit analog-output channels and four TTL-compatible digital signal lines, configurable as inputs or outputs. That combination of functions plugged into a DSP baseboard creates "a complete data-acquisition front end in one slot," said executive vice president Rob Shadduck.
All the I/O channels use crystal delta-sigma converters with 20-bit accuracy, and each channel has a 1-kbyte FIFO for data buffering. The $3,250 PMC/ 16IO2 samples at up to 48 kHz and supports Windows 95, 98 and NT.
Blue Wave also recently rolled a PMC frame grabber: the Datacell PMC/SNP-24, which gears a DSP baseboard for applications in security, machine-vision and industrial inspection systems. At $3,650, the board sports custom circuitry that "performs optional subsampling and region-of-interest generation for maximum flexibility and high-speed readout," Shadduck said.
The board has two banks of 256-k x 24-bit frame-buffer memory, with pixels stored at 24 bits deep. It accommodates a range of video-camera types and accepts multiple camera inputs, software-selectable for either four color cameras or 12 monochrome cameras. It supports real-time image digitization at frame rates between 25 and 30 frames/s.
Making the connection
Other functional areas similarly aren't lacking for new products in the PMC form factor. Megatek Graphics Group of Space Electronics Inc. (San Diego), Concurrent Technologies Inc. (Cincinnati), Alta Technology Corp. (Sandy, Utah) and Peritek Corp. (Oakland, Calif.), for instance, have all brought out PMC graphics boards.
This month, Cyclone will start shipping its PMC56 Ultra2 SCSI LVD (low-voltage differential) board for $297 each in lots of 1,000. For its part, Technobox Inc. (Mount Laurel, N.J.) has just announced a $749 reconfigurable PMC card that blends an Altera Flex 10K70 FPGA with 96 bits of digital I/O. Versions with alternative I/O (fiber-optic and RS-422/485) are in the offing.
But clearly, most of the PMC introductions in recent days have revolved around various communication schemes. Concurrent, for example, recently came out with a 10/100-Mbit Ethernet PMC board based on a Digital Equipment Corp. 21143 Ethernet controller chip. With driver support available for VxWorks, Windows NT, QNX and Solaris, the CL PMC/100 is priced at $488.
Alta, in turn, has unveiled a Gigabit Ethernet board for PMC-a $1,395 model, called PMC/GNIC, that's capable of either 32- or 64-bit bus operation. It was cooperatively designed with Packet Engines Inc. (Spokane, Wash.), according to Clark Roundy, marketing and sales manager at Alta, based on that company's PE-MAC media-access controller chip and G-NIC technology.
The board, said Roundy, can achieve "2 Gbits of full-duplex throughput to a host computer, due to three factors. First, instruction prefetch reduces latency by ensuring that packets are not held up in queues waiting for instructions. Second, dual PCI burst FIFOs enable data pipelining. Third, large external packet buffers maximize throughput by minimizing retransmission during extended bursts."
Further, he said, independent RX and TX descriptor-based DMA processors on the board reduce host-CPU utilization by streaming RX and TX data to and from the host memory without host intervention. "And intelligent interrupt algorithms reduce the number of host interrupts and latency," he said. Also, "transmit packet chaining reduces the host-CPU utilization by transferring multiple packets from the host memory to the PMC/G-NIC adapter with a single interrupt." Drivers are available for Windows NT, Unix and Linux.
Three companies have come out with Fibre Channel PMC boards, all focused on military electronics: DY-4 Systems Inc. (Kanata, Ontario), Vista Controls Corp. (Santa Clarita, Calif.) and Vmetro (Houston). The Vista and Vmetro boards are based on a QLogic Fibre Channel controller chip and a board design licensed from the Delphi Engineering Group (Costa Mesa, Calif.). Vista's FC-PMC is a conduction-cooled respin of Delphi's Fibre Channel PMC, able to withstand -40degreesC to +75degreesC environments.
According to spokesmen for Vista and Vmetro, the Delphi design boasts low latency, minimal host-processor overhead and sustained transfer rates of slightly more than 100 Mbytes/s-twice that of previous products and 99.7 percent of the theoretical maximum performance of Fibre Channel. The flexible board accommodates point-to-point, arbitrated-loop and switched Fibre Channel topologies, as well as copper or fiber. An integrated hub capability implements redundant links. The Vista board starts at $2,495 and the Vmetro board at $2,095.
The PMC-640 from DY-4, built around an intelligent Fibre Channel ASIC, also provides "high data throughput, low latency, real-time transfers and minimized host-processor overhead," said Duncan Young of that company. Also featured, he said, is the "interconnect versatility required by data-intensive applications such as DSP, radar/sonar, network backbones, system clustering, video and image processing, and map display systems." It's priced at $2,500.
SciTech Inc. (Madison, Wis.), in turn, has come to market with a PMC board that accommodates E1, T1 and primary-rate ISDN interfaces. The TCOM4-SC supports 1.544 Mbit/s (T1) to 2,048 Mbit/s (E1, ISDN) data rates. Equipped with a VxWorks driver, it starts at $465 each in lots of 1,000 for a two-channel version, $635 for four channels. An SC Bus expansion port is optional for offloading multimedia traffic from the system bus.
The ANSI-standard Raceway crossbar switching fabric developed by Mercury Computer Systems (Chelmsford, Mass.) has been implemented on PMC by two board vendors: Pentek Inc. (Upper Saddle River, N.J.) and Synergy Microsystems. Delivering multiple simultaneous data paths with an aggregate bandwidth of more than 1 Gbyte/s, Raceway "is one of the industry's fastest, nonproprietary interface solutions," said Pentek vice president Rodger Hosking.
Both Pentek's Model 7106, starting at $1,795, and Synergy's PXB2, starting at $1,995, route Raceway through a VME board's P2 connector.
Elsewhere in the gigabit realm, General Micro Systems has a PMC networking board based on the Hypernet chip and technology of WideBand Corp. It can sustain aggregate data rates of 800 Mbits/s at 100 meters over standard UTP-5 wiring. Optional fiber-optic links extend that to 3,000 meters in multimode operation or 40,000 meters in single-mode.
WideBand Gigabit networks "provide the means for data synchronization, thereby eliminating the need for 'fillers' in each data packet to allow collision detection. The data-flow control mechanism in a WideBand network is simple, robust and effective." The GMS board supports Windows NT, VxWorks and Real/IX. It's priced at $560.
Sederta Inc. (St. Laurent, Quebec) has fielded another novel communications scheme in a PMC and other formats. The SD-PCI-200 implements a real-time interconnection scheme called SedNet, which is based on IEEE 1394 and handles links among as many as 64 computers. Running at 100 or 200 Mbits/s, but likely to scale up to faster 1394 speeds, SedNet provides "fully transparent communication management," said vice president Michel Lefebvre, along with "full real-time synchronization among all nodes."
SedNet can be implemented in a point-to-point, daisy chain or tree topology. The PMC board version provides three ports and is priced at $695. Operating systems supported include VxWorks, QNX, Windows NT, AIX, Solaris and Phar Lap.
The PMC standard is even flexible enough to support a processing subsystem, and Ixthos Inc. (Leesburg, Va.), a subsidiary of DY-4 Systems, has used it to field single- and quad-DSP configurations based on the Analog Devices Inc. Sharc DSP. And last month, SBS Embedded Computers (Encinitas, Calif.) launched a PMC processor module called Palomar, based on a PowerPC 750 microprocessor. It's priced at $2,500 in single quantities.
There were no major hindrances to implementing a processor on PMC, said Bret Farnum, SBS director of sales.
Alta Technology Corp.
Issue of January 4, 1999; EETInfo No. 616
Blue Wave Systems Inc.
Issue of January 4, 1999; EETInfo No. 617
Concurrent Technologies Inc.
Issue of January 4, 1999; EETInfo No. 618
Cyclone Microsystems Inc.
Issue of January 4, 1999; EETInfo No. 619
DY-4 Systems Inc.
Issue of January 4, 1999; EETInfo No. 620
General Micro Systems Inc.
Issue of January 4, 1999; EETInfo No. 621
General Standards Corp.
Issue of January 4, 1999; EETInfo No. 622
Issue of January 4, 1999; EETInfo No. 623
Megatek Graphics Group
Issue of January 4, 1999; EETInfo No. 624
Issue of January 4, 1999; EETInfo No. 625
Issue of January 4, 1999; EETInfo No. 626
SBS Embedded Computers
Issue of January 4, 1999; EETInfo No. 627
SBS GreenSpring Modular I/O
Issue of January 4, 1999; EETInfo No. 628
Issue of January 4, 1999; EETInfo No. 629
Issue of January 4, 1999; EETInfo No. 630
Issue of January 4, 1999; EETInfo No. 631
Issue of January 4, 1999; EETInfo No. 632
Vista Controls Corp.
issue of January 4, 1999; EETInfo No. 633
Issue of January 4, 1999; EETInfo No. 634