TXC-06880BIOG Transwitch Corporation, TXC-06880BIOG Datasheet - Page 72

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TXC-06880BIOG

Manufacturer Part Number
TXC-06880BIOG
Description
Manufacturer
Transwitch Corporation
Datasheet

Specifications of TXC-06880BIOG

Operating Supply Voltage (typ)
1.8/3.3V
Operating Temperature Classification
Industrial
Mounting
Surface Mount
Lead Free Status / RoHS Status
Not Compliant

Available stocks

Company
Part Number
Manufacturer
Quantity
Price
Part Number:
TXC-06880BIOG
Manufacturer:
SAMWHA
Quantity:
34 000
Envoy-CE2 Device
DATA SHEET
TXC-06880
7 2 o f 12 2
6.5.3 PAUSE Control Frame Generation
6.5.3.1 Automatic PAUSE Frame Generation
6.5.3.2 Host Initiated PAUSE Frame Generation
PAUSE state until the internal timer counts down to zero, in which case Envoy-CE2 will
resume transmission of data frames to the remote device. If a PAUSE control frame with a
new non zero pause_time parameter is received, the new pause_time is loaded into the
internal down counter and the Envoy-CE2 stays in the PAUSE state for the time specified by
the new pause_time. When a PAUSE frame with a timer parameter value of zero is received,
the Envoy-CE2 will resume sending data frames to the remote device.
There are two modes for PAUSE Control Frame generation: Automatic PAUSE frame
generation and Host initiated PAUSE frame generation.
In this mode, when the remote device sends Data frames to the Envoy-CE2 and the Ingress
FIFO fills to a programmable High Watermark, Envoy-CE2’s flow control mechanism is
triggered and automatically generates a PAUSE control frame, which is sent after the current
transfer is over. Envoy-CE2 transmits the frame to the remote device and backpressures the
remote device. The pause_time value for the generated PAUSE control is programmable.
Once the PAUSE control frame is transmitted, Envoy-CE2 will re-transmit another PAUSE
control frame, every pause_retransmit_time, if a programmable Low Watermark is not
reached in the Ingress FIFO. The effect of the re-transmitted PAUSE control frame on the
remote device is that, it (remote device) is held in the PAUSE state and does not transmit
data frames to Envoy-CE2. The value of pause_retransmit_time is programmable and is kept
by the pause retransmit counter (down counter). In the event the Low Watermark is reached
before the pause retransmit counter counts down to zero, Envoy-CE2 will transmit a PAUSE
control frame with a pause_time value of zero to the remote device held in the pause state.
The PAUSE control frame with pause_time value of zero will initiate resumption of
transmission of data frames from the remote device to the Envoy-CE2.
The Host device can query Envoy-CE2 for the status of each Ingress FIFO (per channel). The
values for the indication of near full status and near empty status, are programmable. They
are the Ingress FIFO Control High and Low Watermarks associated with the Ingress FIFOs.
The Envoy-CE2 provides the host with the ability to generate a PAUSE control frame from the
Envoy-CE2. This is done by the Host enabling the PAUSE generate configuration bit. The
Host can generate a PAUSE control frame with a non-zero value for pause_time, to the
remote device across the link with Envoy-CE2, when the Ingress FIFOs reach the High
Watermark and also generate a PAUSE control frame with a null value for pause_time, when
the Ingress FIFO reaches the Low Watermark. This allows the Host to regulate the flow
control mechanism.
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Operation
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PRELIMINARY TXC-06880-MB, Ed. 4
February 2005

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