30 / 91 page

IP178C
Preliminary Data Sheet
30/91
October 27, 2005
Copyright © 2004, IC Plus Corp.
IP178C-DS-R09
2.1
Flow control
IP178C jams or pauses a port, which causes output queue over the threshold. Its link partner will defer
transmission after detecting the jam or pause frame. A port of IP178C defers transmission when it
receives a jam or a pause frame.
When CoS is enabled, IP178C may disable the flow control function for a short term to guarantee the
bandwidth of high priority packets. A port disables its flow control function for 2 ~ 3 seconds when it
receives a high priority packet. It doesn’t transmit pause frame or jam pattern during the period but it still
responses to pause frame or jam pattern.
The flow control function can be enabled by pulling up pin 75 X_EN or by programming MII register
30.1.10.