HC4GX15 Datasheet, PDF (396/668 Pages) Altera Corporation – HardCopy IV Device Handbook

1–132
Figure 1–108. Receiver Detect, Successfully Detected
powerdown[1:0]
2'b10(P1)
tx_detectrxloopback
Chapter 1: HardCopy IV GX Transceiver Architecture
Functional Modes
pipephydonestatus
pipestatus[2:0]
3'b000
3'b011
Figure 1–109. Receiver Detect, Unsuccessfully Detected
powerdown[1:0]
2'b10 (P1)
tx_detectrxloopback
pipephydonestatus
pipestatus[2:0]
3'b000
Compliance Pattern Transmission Support
The LTSSM state machine can enter the polling.compliance substate where the
transmitter is required to transmit a compliance pattern as specified in the PCI
Express (PIPE) Base Specification 2.0. The polling.compliance substate is intended to
assess if the transmitter is electrically compliant with the PIPE voltage and timing
specifications.
The compliance pattern is a repeating sequence of the following four code groups:
■ /K28.5/
■ /D21.5/
■ /K28.5/
■ /D10.2/
The PCI Express (PIPE) protocol requires the first /K28.5/ code group of the
compliance pattern to be encoded with negative current disparity. To satisfy this
requirement, the PIPE interface block provides the input signal
tx_forcedispcompliance. A high level on tx_forcedispcompliance forces
the associated parallel transmitter data on the tx_datain port to transmit with
negative current running disparity.
HardCopy IV Device Handbook Volume 3
© June 2009 Altera Corporation