This article describes some of the differences to consider when purchasing an IEEE-1394 PCI / PCMCIA host adapter card.
Some of these differences can be attributed to the type of IEEE-1394 Open Host Controller Interface (OHCI) (or chipset) used by the card. Common chipsets include: Lucent/Agere, VIA, and Texas Instruments (TI).
MAXIMUM NUMBER OF DMA CHANNELS
The number of simultaneous DMA channels (also known as isochronous transmit / receive contexts) supported by the card determines the number of IEEE-1394 cameras that can be running (streaming images) at the same time. Although the 1394a standard limits the maximum number of simultaneous isochronous channels to 16, there is currently no host adapter that is capable of supporting 16 channels.
FIFO BUFFER SIZE
The size of the on-chip isochronous and asynchronous receive and transmit FIFOs for the 1394 packets can affect 1394 streaming performance. Larger FIFO's generally result in better recovery from PCI bandwidth issues.
CABLE INTERFACE
Most PCMCIA cards for laptops and some PCI cards for desktop systems are built for use with a 4-pin FireWire cable, which will not work with PGR cameras that require a 6-pin connector (the additional two pins provide power). Some FireWire accessory manufacturers sell cables that have one 4-pin end and one 6-pin end. However, the cameras still require power to be provided. See the related Knowledge Base article below for more information.
IEEE-1394b SUPPORT
Some IEEE-1394 card manufacturers are now offering 1394b host adapters. 1394b is a significant enhancement to the basic 1394 specification, and is fully backwards compatible with the current 1394-1995 and 1394a specifications. Consult the related Knowledge Base article below for more information.
WHICH CARD SHOULD I BUY?
In general, PGR has had positive experiences with IEEE-1394 PCI cards based on the TI and Lucent/Agere chipset. Aside from the trade-offs listed above, there are no signficant performance variations, particularly between cards based on the same chipset. Some vendors which we have used to ship with our cameras in the past are listed in the Related Article 131 below.
SUMMARY
| Chipset | Max DMA Channels | Isochronous Receive FIFO Buffer | Isochronous Transmit FIFO Buffer | Asynchronous Transmit FIFO Buffer | Datasheet |
| VIA Fire II VT6306 | 4 | 2K | 2K | 2K | |
| Lucent/Agere FW323 06 | 8 | 4K | 4K | 2K | |
| Texas Instruments TSB12LV21B | 4 | 4K | 4K | 4K | |
| Texas Instruments TSB12LV26 | 4 | Not available | Not available | Not available | |
| Texas Instruments TSB82AA2 (1394b) | 5 | 2K | 2K | 5K |
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