OPERATION
Copyright 2007
5-27
S SC150e HARDWARE REFERENCE
Media Circuitry
Rx
Tx
Rx
Tx
Internal
PLL and Data
Recovery
MECHSWITCH
FO
Conv
FO
Conv
Fiber Optic Bypass Switch
(Optional)
RX
ENABLE
TX
ENABLE
OFF
ON
OFF
ON
OFF
ON
OFF
ON
ENABLE WIRE
LOOPBACK
INSERT
Figure 5-9 Insert Mode
5.11.4 Holdoff Mode
To enable Holdoff, set CSR8[1] OFF. The Holdoff feature automatically slows down
CPU data writes to the S SC150e memory when the Transmit FIFO becomes
full. The Transmit FIFO serves as a buffer between the S SC150e memory
and the S SC150e network.
The Transmit FIFO can become full when the host CPU is writing to S
SC150e memory faster than the network can absorb the data. If a CPU is capable of
writing to the S SC150e memory on the PCI bus at such a rate that the
Transmit FIFO becomes full (1024 deep), data could be lost. In the event that the
Transmit FIFO becomes full, the hardware will automatically extend the next write cycle
until the Transmit FIFO empties at least one message. This prevents the loss of any data
and is transparent to the user.
Summary of Contents for SCRAMNet+ SC150e
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