ACC Utilities Reference Guide

TTGEN - ZCOM System Table Generator
Creating the TTGEN Configuration File
Chapter 246
The firmware on the 8-channel PCI cards use fixed sized I/O buffers to
hold inbound and outbound data messages and protocol packets. If a data
message is larger than the buffer size, multiple buffers are allocated to
hold the message. The buffer size may be increased or decreased to allow
for the most common expected message size. If the buffer size is too small
then messages are fragmented by the firmware, increasing ACC CPU
overhead. If the buffer size is too large then buffer space is being wasted
by short messages. The size of the internal header/trailer of the buffer us
16 bytes. Protocol headers are in addition to this. The default buffer size
is 160 bytes.