TXC-06885BIOG Transwitch Corporation, TXC-06885BIOG Datasheet - Page 69

• Manufacturer Part Number: TXC-06885BIOG
• Manufacturer: Transwitch Corporation

Specifications of TXC-06885BIOG

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

PRELIMINARY TXC-06885-MB, Ed. 6A
February 2005
6.2 SPI-3 TO SMII/GMII FLOW CONTROL OPERATION
6.2.1 SPI-3 Input Operation
6.2.1.1 Input SPI-3 Data Flow:
Frame format at SPI-3 Output Interface
VLAN Tag Frame format at SPI-3 Output Interface
Frame with Extension Field at SPI-3 Output Interface
At the SPI-3 input interface, frames are transferred from the Link or PHY layer device to the
Envoy-CE4. An Envoy-CE4 channel is selected for data transfer, by the Link or PHY layer
device. In PHY layer mode, the Link layer device monitors the “Buffer Space Available”
signals, STPA/PTPA and selects an Envoy-CE4 channel for data transfer, based on the
Transmit packet available signals (STPA and PTPA). In Link layer mode, the PHY layer
device transfers frame based on Envoy-CE4’s read enable signal. Once a data transfer
begins, the Link/PHY layer device qualifies the frame data being transferred into the
channel’s Egress FIFO, with the read enable/data valid signal. The “Buffer Space Available”
signals reflect the full status of the channel’s Egress FIFO and get de-asserted when the
associated Egress FIFO becomes near full (near full level is programmable). When the
Egress FIFO is configured for Store and Forward mode, frames received with the SPI-3 error
pin asserted, will be either discarded or errored and a count of the discarded and errored
frames is kept.
When the egress FIFO is configured for Store and Forward mode, frames received with the
SPI-3 error pin asserted are discarded and will not show up on the Ethernet port. When the
egress FIFO is configured for Streaming mode, frames received with the SPI-3 error pin
asserted will show up on the Ethernet port with an additional four bytes of bad CRC
appended to it.
Destination
Destination
(6 bytes)
Address
(6 bytes)
Destination
Address
(6 bytes)
Address
(6 bytes)
Address
Source
(6 bytes)
Address
Source
(6 bytes)
Address
Source
(4 bytes)
- Operation -
Length/Type
VLAN
Tag
(2 bytes)
Length/Type
(2 bytes)
Length/Type
(2 bytes)
(46 to 1500
bytes)
Data
(46 to 1500 bytes)
(46 to 1500 bytes)
Data
Frame Check
Data
Sequence
(4 bytes)
Envoy-CE4 Device
Frame Check
Frame Check
DATA SHEET
Sequence
(4 bytes)
Sequence
(4 bytes)
Extension
TXC-06885
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