Image Transfer Via 1394A And 1394B - AVT Pike Technical Manual

FireWire
Technical detail
Transmission mode
Devices
Number of cameras
Number of DMAs
Real time capability
Available bandwidth acc. IIDC
(per cycle 125 µs)
Max. image bandwidth
Max. total bandwidth
Number of busses
CPU load
Gaps

Image transfer via 1394a and 1394b

1394a
Half duplex (both pairs needed)
400 Mbit/s data rate
aka: a-mode, data/strobe (D/S)
mode, legacy mode
4096 bytes per cycle
~ 1000q @ 400 Mbit/s
For further detail read Chapter
31.25 MByte/s
~45 MByte/s
Multiple busses per PC
limit: PCI bus
Gaps negatively affect asynchro-
nous performance of widespread
network (round trip delay),
reducing efficiency
Table 6: Technical detail comparison: 1394a and 1394b
Note The bandwidth values refer to the fact:
1 MByte = 1024 kByte
1394b
Full duplex (one pair needed)
1 Gbit/s signaling rate, 800
Mbit/s data rate
10b/8b coding (Ethernet), aka:
b-mode (beta mode)
Up to 63 devices per network
Up to 16 cameras per network
4 to 8 DMAs (parallel) cameras / bus
Image has real time priority
Frame rates
Almost none for DMA image transfer
No gaps needed, BOSS mode for
8192 bytes per cycle
~ 2000q @ 800 Mbit/s
(@1 GHz clock rate)
on page 201.
62.5 MByte/s
~85 MByte/s
Multiple busses per PC
limit: PCI (Express) bus
parallel arbitration
PIKE Technical Manual V4.1.0
31