PC-104-based image-processing boards pack functionality
Andrew Wilson
Editor at Large
Since IBM Corp. (White Plains, NY) introduced the first open-architecture PC, board-level vendors have sought to add increased processing capability through the introduction of PC add-in boards. For image-processing applications, their initial products included individual boards that were used to capture, process, and display images.
Often linked by proprietary high-speed image-transfer buses, these boards offered systems developers a building-block approach to developing machine-vision systems.
With the increasing density of integrated circuits (ICs) and the availability of high-speed PC-based buses such as the 132-Mbyte/s peripheral connect interconnect (PCI) bus, board suppliers found that they could incorporate much of the functionality of individual boards into single-slot processing solutions. Consequently, over the past few years, board fabrication has led to the introduction of single, PCI-based image-processing boards. And, whereas many boards incorporate broadcast standard interfaces and noninterlaced super-video-graphics-adapter (SVGA) display capability, others can interface to high-speed linescan cameras.
Small but rugged
While the emergence of such board products has eased the development of machine-vision and image-processing systems, developers are always trying to lower costs. To do so, they need to choose from a variety of image-capture, processing, and display modules to tailor their image-processing systems and to minimize any inherent redundancy of single-board solutions.
Enter the PC-104 and PC-104+ boards. Developed by Ampro Computers (San Jose, CA), the PC-104 specification describes a standard for using the PCI bus in embedded applications. PC-104 modules are 3.6 x 3.8 in. and self-stacking, allowing easy expansion without backplanes or card cages. And because PC-104-based systems are PC-compatible, they can be used with hundreds of existing PC development tools and software packages. This enables developers to reduce system-development costs and to speed product time to market.
The PC-104 cards are smaller than the older ISA-bus boards. But, because the 104 pins of the PC-104 bus connectors are occupied with PC/AT signals, a 120-pin stackable connector has been developed to handle the additional signals of the 32-bit PCI bus. The combination of PC-104 with PCI, called PC-104Plus (PC-104+), is compatible with the current 33-MHz PCI bus and future 66-MHz versions.
For imaging-system developers, the approximately 2000 boards available worldwide from more than 100 vendors has placed PC-104 based systems in the mainstream. Products available on the bus form factor include modules for networking, processing, analog-to-digital (A/D) and digital-to-analog (D/A) conversion, image capture, monitor display, digital compression, and motion control.
Image-capture modules
Like their extended-industry-standard-architecture (EISA) counterparts of the past, many PC-104 and PC-104+ modules for image processing perform single functions such as image capture, processing, or display. Due to the small size of the PC-104 form factor, most image-capture boards digitize video images in standard broadcast video formats such as NTSC, PAL, and S-Video (see Fig. 1). In addition to digitizing these standard formats, many boards are also capable of handling multiple video inputs, general-purpose input/output (I/O) signals, and vertical and horizontal sync outputs for genlocking video sources. Many boards are also available in both PC-104 and PC-104+ formats.
For example, the PC-104 frame grabber from InSync Technologies (San Leandro, CA) runs on 16-bit PC-104 buses and can capture both NTSC and S-Video signals into a 2-Mbyte on-board buffer in real time. The board is also offered in a PAL version. Because the board uses the ISA bus, its image-transfer rate to the host CPU is limited to 4 Mbytes/s.
To speed up the data-transfer rate, other vendors are incorporating the PC-104+ specifications into their boards. For example, the Imagenation (Beaverton, OR) PXC-200 PC-104+ color frame grabber provides four multiplexed inputs that accept color video from NTSC and PAL sources. While one input can be reserved for S-Video, the board also supports YCrCb and RGB outputs. Acting as a bus master, it can transfer video data to memory in real time while the processor is running other applications.
Designers interested in using such PC-104 products in their next-generation embedded image-processing designs should carefully consider the software support provided by manufacturers. Often, this is packaged in the form of a software-development kit (SDK) that includes DOS drivers and a suite of demonstration programs. The SDK offered with the Model 311 PC-104+ frame grabber from Sensoray (Tigard, OR), for example, includes a C-language sample program that captures and saves color and monochrome images and illustrates the board`s scaling feature. In addition, an available 32-bit dynamic link library supports interrupts and multiple DMA buffers that can be scattered within host memory.
Pick a processor
Choosing a host processor to support image-capture boards proves complex when specifying a PC-104-based system. Although more than 30 single-board-computer (SBC) boards are now available for this purpose, many sport x86-to-Pentium class processors, and some come with cooling fans attached. Like the large SBCs of the past, the latest range of PC-104 SBCs integrate all of the functionality and more of PC/AT-based motherboards (see Fig. 2).
Where basic functions, such as central processing unit (CPU), memory, line printer Terminal LPT), integrated drive electronics (IDE), and keyboard are sufficient, developers can chose from SBC products such as the MOSlite from JUMPtec (San Diego, CA). Developed to add PC functionality into embedded equipment at low-cost, this board is equipped with a 386SX CPU, hard-disk, printer-port, serial-port, and keyboard interfaces.
Using the board`s integrated interface for a single- or multiline character display and matrix keyboard interface, developers can build an inexpensive operator interface. And, an integrated BIOS flash disk with up to 2.9 Mbytes of memory enables the system to start and run an application without the need for an external drive.
Often, however, especially in image-processing and vision applications, a more-powerful, integrated CPU is required. Although more expensive, such PC-104 SBCs integrate higher performance processors, faster memory, and added I/O capability. To meet the demands of compute-intensive inputs such as video, PC-104 SBC vendors such as WinSystems (Arlington, TX) and EEPD North America (Plantation, FL) have developed powerful 5 x 86 class and Pentium SBCs.
As a 5 x 86-based SBC, the WinSystems PCM-586 board is PC-AT compatible and, in embedded applications, can operate without disks, keyboard, or monitor. With an on-board 133-MHz AMD5x86 CPU, this SBC includes a 16-kbyte cache, AT-peripheral core logic, two communication channels, floppy-disk controller, IDE controller, keyboard and mouse controllers, and a printer port.
Supplied with up to 32 Mbytes of extended-data-output (EDO) RAM, the board allows developers to substitute on-board EPROM where the operating environment is too harsh for mechanical hard drives. According to WinSystems, the board operates with ROM-DOS, MS-DOS, Linux, Windows-3.1/95/98/CE/NT, and real-time operating systems such as QNX, VxWorks, and RTXC.
For even higher performance, SBC vendors are providing PC-104+ based processors with 233-MHz Pentium MMX processors and 300-MHz AMD-K6 CPUs. The EEPD Profive product series, for example, is based on the PC-104+ standard. The company`s CPU-P5 board is based on the Intel 430 TX chipset and accommodates Pentium 75- to 200-MHz, Pentium MMX 166/200/233-MHz, and AMD-K6 266/300-MHz processors. By using a Socket 7-compatible ZIF-socket for the CPU, developers can upgrade the processor at any time.
In addition to the ISA-bus and PCI-bus connectors for the PC-104+ standard, the Profive CPU-P5 board contains two RS-232 compatible serial ports, an extended capabilities port/enhanced parallel port (EPP)-compatible parallel port, a 2.88-Mbyte FDD controller, a PCI-IDE controller, a single universal serial bus (USB) port, and a PS/2-compatible keyboard and mouse controller. A dual in-line memory module-small outline (DIMM-SO) II module that supports EDO and SDRAM memories allows developers to change memory sizes between 2 and 64 Mbytes.
Display control
For many embedded image-processing and vision-system applications, developers usually make a simple pass or fail decision for selecting a display control, especially when they do not need to show captured or processed images. However, to perform systems development, they often need to visualize captured image data. In embracing the PC-104 and PC-104+ standards, developers can have the best of both specifications.
To develop an embedded image-processing system, designers can take advantage of off-the-shelf image-capture, processing, and display cards. Once the system has been developed, they can deploy it without using any display image modules. Just as image-capture boards based on the PC-104 standard embrace broadcast standards, and processing modules similarly incorporate AT-based functionality, the available display modules are PC-specific and support the VGA or SVGA standards developed by IBM Corp. (see Fig. 3).
Using chipsets from Chips and Technologies--now part of Intel Corp. (Santa Clara, CA)--and from Cirrus Logic (Fremont, CA), PC-104 display controllers offer developers single-board, small-footprint, graphics display solutions. Typical of these offerings, the AX10430 from Axiom Technology (City of Industry, CA) is an SVGA display board that plugs into any PC-104 carrier. Supporting graphics modes from 640 x 480 to 1280 x 1024 pixels, the board uses the Cirrus GD542x series of display controllers and a 1-Mbyte display memory that can be upgraded for high-speed video access.
Other options
Fortunately for designers of embedded image-processing systems, image capture, processing, and display controller boards for the PC-104 and PC-104+ standards provide additional options. Other available boards include networking, data acquisition, motor control, reconfigurable processors, and time-stamp circuits (see Fig. 4). With these products, developers can configure a range of PC-based embedded systems for machine-control, industrial-automation, scientific, and medical-vision applications.
In the future, as PC-104+ boards replace older PC-104-based products in embedded applications, the associated imaging systems will become more like their PCI-based counterparts of today. Indeed, as semiconductor vendors continue to cram more logic into single ICs, manufacturers will likely offer complete image processors--including video capture, processing, and display capabilities--on boards that measure just 3.6 x 3.8 in. And, once again, developers of PC-104+ boards will have to evaluate another set of price/performance trade-offs.
FIGURE 1. Featuring a 3.6 x 3.8-in. size, PC-104 and PC-104+ image-capture modules are self-stacking and can be expanded without backplanes or card cages with other PC-104 CPU, display controller, network, and digital-to-analog cards. Available image-capture boards include the the eGrabber-1 from Phytec America.
FIGURE 2. To build a PC-compatible system with PC-104 bus cards, developers can choose from a range of processor cards that host such CPUs as 386s, low-power 486s, or Pentiums. Available CPU boards that use the PC-104 form factor include the MSMP5V/N, a Pentium-5 processor from Digital-Logic, the TC586, a 133-MHz PC from DSP Design, and a 66-MHz low-power 486 PC from Real Time Devices.
FIGURE 3. To display images captured and processed with PC-104-bus cards, a number of different types of display controllers are available, including VGA, SVGA, and flat-panel-display driver cards. And because such systems are essentially PCs with a different form factor, the development tools used for PCs can be harnessed to develop PC/104-based systems.
FIGURE 4. To build a complete image-processing system around the PC-104, developers must look to harness readily available Ethernet, A/D boards, motor controllers, and other peripherals. Whereas these boards are available from more than 100 vendors, typical boards include a 16-bit, 200-kHz analog I/O module from Diamond Systems and a PF2000 reconfigurable FPGA module from Derivation Systems.
Company Information
For information on additional suppliers of image-processing boards, see the 1999 Vision Systems Design Buyers Guide (Vision Systems Design, Feb. 1999, p. 90).
Ampro Computers
San Jose, CA 95138
E-mail: [email protected]
Web: www.ampro.com
Cirrus Logic Inc.
Fremont, CA 94538
(510) 623-8300
Fax: (510) 226-2270
Web: www.cirrus.com
IBM Corp.
White Plains, NY 10601
(800) 426-4968
Fax: 914-288-1178
Web: www.ibm.com
Intel Corp.
Santa Clara, CA 95052
(800) 548-4725
Web: www.intel.com
