TXC-06885BIOG Transwitch Corporation, TXC-06885BIOG Datasheet - Page 18

• 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

Envoy-CE4 Device
DATA SHEET
TXC-06885
1 8 o f 12 8
2.1.7.2 Link Mode
Figure 8. Envoy-CE4 in Link Layer Mode
In Link layer mode, the following SPI-3 interface naming convention is used, per the OIF
SPI-3 specification. Packets received at the Ethernet receive interface, are stored in the
Ingress FIFO and transmitted on the SPI-3 Tx interface (SPI-3 output for Envoy-CE4).
Packets received at the SPI-3 Rx interface (SPI-3 input for Envoy-CE4), are stored in the
Egress FIFO and transmitted on the Ethernet transmit interface.
At the Transmit Interface (SPI-3 output) in Link layer mode, the device monitors the STPA and
PTPA signals for indication of buffer space availability in the PHY device. In the event the
PHY device indicates FIFO buffer availability by asserting its Transmit Packet available status
signal and there is packet data available for transfer to the port, then Envoy-CE4 will transfer
packet data to the PHY port. The transfer may be chunk-based or packet-based. In chunk
mode, a specified number of bytes (chunk) is transferred to a PHY device port, before the
Envoy-CE4 selects another PHY port for packet data transfer. If an end of packet is
encountered, a reselection also occurs. Chunk sizes are programmable from 8 to 2040 bytes,
in 8 byte increments. In packet based transfer, Envoy-CE4 will transfer the complete packet
to a PHY port and will pause data transmission when the PHY device port indicates its FIFO
is almost full by de-asserting its Transmit Packet available signal. Selection of another PHY
port is done once a complete packet has been sent to the current PHY port. Port selection is
accomplished using the first come, first serve, round robin algorithm. At the Receive interface
(SPI-3 input), the PHY device will transfer packet data to the Envoy-CE4, which will globally
backpressure the PHY device when any Port’s Egress FIFO becomes almost full.
Device
Layer
PHY
RDAT[31:0]
TDAT[31:0]
RMOD[1:0]
TMOD[1:0]
TADR[7:0]
RPRTY
-
TPRTY
RFCLK
TFCLK
RENB
RSOP
REOP
RERR
TENB
TSOP
TEOP
TERR
STPA
PTPA
RVAL
Functional Description
RSX
TSX
-
OSPICLK
OSPITENB
OSPID[31:0]
OSPIPRTY
OSPISOP
OSPIEOP
OSPIERR
OSPITSX
OSPIMOD[1:0 ]
OSPISTPA
OSPIPTPA
OSPITADR[7:0]
ISPICLK
ISPIRENB
ISPID[31:0]
ISPIPRTY
ISPIRVAL
ISPISOP
ISPIEOP
ISPIERR
ISPIRSX
ISPIMOD[1:0]
ISPITENB
ISPISTPA
ISPIPTPA
ISPITADR[7:0]
ISPITSX
OSPIRENB
OSPIRVAL
OSPIRSX
Envoy-CE4
PRELIMINARY TXC-06885-MB, Ed. 6A
February 2005