Point Grey Research Grasshopper Technical Reference
Camera Operations and Features
Revised 26-Nov-10
Copyright (c) 2010 Point Grey Research Inc.
25
1024x768
RGB
••••
••••
••••
•••
1024x768
Y16
••••
••••
••••
••••
••••
••••
••••
••••
••••••
1024x768
Y8
••••
••••
••••
••••
••••
••••
••••
••••
••••
1280x960
YUV422
•••
•••
•••
•••
1280x960
RGB
•••
•••
•••
•••
1280x960
Y16
•••••• ••••••
••••••
••••••
1280x960
Y8
•••••• ••••••
••••••
••••••
•••
1600x1200
YUV422
••
••
••
••
1600x1200
RGB
••
••
••
1600x1200
Y16
••••
••••
••••
••••
1600x1200
Y8
••••
••••
••••
••••
4.3. Frame Rates and Camera Bandwidth
[
This section is recommended for advanced users only, and is not
meant to address all possible applications of the Grasshopper camera.
4.3.1. Maximum Number of Cameras on a Single Bus
A single IEEE-1394 OHCI host adapter generally constitutes a single “bus”. There are four
elements that limit the number of cameras that can be used on the same 1394 bus:
• Although the 1394b standard limits the maximum number of simultaneous isochronous
channels to 16, there is currently no host adapter that is capable of supporting 16
channels. Host adapters based on the LSI chipset such as the FirePRO™ 1394b PCI
Express card can support up to 8 simultaneous DMA channels (or contexts). Host
adapters based on the TI chipset can support at most 4 simultaneous DMA channels (or
contexts). There are no known 1394b chipsets that allow 16 simultaneous DMA contexts.
See
Knowledge Base Article 146 for more information.
• The maximum bandwidth of the 1394b bus is 800Mbits/sec (10240Bytes/packet - 8000
cycles/sec). The usable bandwidth as defined by the 1394 Trade Association and
enforced by the Microsoft Windows 1394 driver stack (1394bus.sys, ohci1394.sys, etc.) is
approximately 80% or 80MBytes/sec (8192 bytes/packet). The remaining 20% of the
bandwidth is allocated for asynchronous communication (e.g. register reads/writes).
Outside of the Microsoft stack, it may be possible to allocate up to 9830 bytes/packet.
To Next Page
Loading...
