Firewire connection capabilities – ALLIED Vision Technologies Guppy PRO F-503 User Manual
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FireWire
Guppy PRO Technical Manual V4.0.0
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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.
Figure 3: 1394b data transmission
Note
How to extend the size of an isochronous packet up to 11.000
byte at S800:
•
see register 0xF1000048, ADV_INQ_3, Max IsoSize [1]
in
Table 124: Advanced register: Advanced feature
•
see Chapter
Cycle Sync: 1394b
Parallel arbitration, handled by BOSS, can eliminate gaps