Allied Vision Technologies Pike Manual de instrucciones descargar pdf (Pagina 23)

FireWire

PIKE Technical Manual V4.0.0

In case of 1394b no gaps are needed due to parallel arbitration, handled by

bus owner supervisor selector (BOSS) (see the following diagram). Whereas

1394a works in half duplex transmission, 1394 does full duplex transmission.

Additional devices may be added up to the overall capacity of the bus, but

throughput at guaranteed minimum service levels is maintained for all

devices with an acknowledged claim on the bus. This deterministic feature is

a huge advantage for many industrial applications where robust performance

is required. Such is the case when it is not acceptable to drop images within

a specific time interval.

FireWire connection capabilities

FireWire can connect together up to 63 peripherals in an acyclic network

structure (hubs). It allows peer-to-peer device communication (between dig-

ital cameras), to take place without using system memory or the CPU.

But even more importantly, a FireWire camera can directly, via direct mem-

ory access (DMA), write into or read from the memory of the computer with

almost no CPU load.

FireWire also supports multiple hosts per bus. FireWire requires only a cable

with the correct number of pins on either end (normally 6 or 9). It is

designed to support plug-and-play and hot swapping. Its six-wire cable can

supply up to 54 W of power per port at 36 V, allowing moderate-consumption

devices to operate without a separate power cord.

Figure 3: 1394b data transmission

Cycle Sync: 1394b

Parallel arbitration, handled by BOSS, can eliminate gaps

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Allied Vision Technologies Pike Manual de instrucciones Pagina 23