Guppy PRO Technical Manual
V4.1.2
234
Maximum ISO packet size
Use this feature to increase the MaxBytePerPacket value of Format_7 modes.
This overwrites the maximum allowed isochronous packet size specified by
IIDC V1.31.
Example
For isochronous packets at a speed of S800 the maximum allowed packet size
(IIDC V1.31) is 8192 byte. This feature allows you to extend the size of an
isochronous packet up to 11.000 byte at S800. Thus, the isochronous
bandwidth is increased from 64 MByte/s to approximately 84 MByte/s. You
need either PCI Express or PCI-X (64 bit).
The Maximum ISO packet size feature to
•
to reduces the asynchronous bandwidth available for controlling cameras
by approximately 75%
•
to may lead to slower responses on commands
•
to is not covered by the IEEE 1394 specification
•
to may not work with all available 1394 host adapters.
Note
If the SOFT_RESET has been issued, the camera no longer
responds to further read/write requests.
You might detect errors of incomplete 1394 transactions.
Register
Name
Field
Bit
Description
0xF1000560 ISOSIZE_S400 Presence_Inq [0]
Indicates presence of this feature (read only)
---
[1 to 5]
Reserved
ON_OFF
[6]
Enable/Disable S400 settings
Set2Max
[7]
Set to maximum supported packet size
---
[8 to 15] Reserved
MaxIsoSize
[16 to 31] Maximum ISO packet size for S400
0xF1000564 ISOSIZE_S800 Presence_Inq [0]
Indicates presence of this feature (read only)
---
[1 to 5]
Reserved
ON_OFF
[6]
Enable/Disable S800 settings
Set2Max
[7]
Set to maximum supported packet size
---
[8 to 15] Reserved
MaxIsoSize
[16 to 31] Maximum ISO packet size for S800
Table 141: Advanced register: Maximum ISO packet size