核心内容摘要
大菠萝的福建奇遇:在时光的茶香里,捕捉最鲜活的人口脉动
一� 基本概念�频周期性信令LFPSLow frequency periodic signalingLow frequency periodic signaling (LFPS) is used for side band communication between the two ports across a link that is in a low power link state. It is also used when a link is under training, or when a downstream port issues Warm Reset to reset the link.For x2 operation, LFPS signals are only transmitted on the Configuration Lane.SCD1/SCD2SuperSpeedPlus Capability Declaration (SCD) is a step for a SuperSpeedPlus port, while in the Polling.LFPS substate, to identify itself as SuperSpeedPlus capable by transmittingPolling.LFPS signals with specific patterns unique to SuperSpeedPlus ports. This section defines SuperSpeedPlus specific patterns in SCD1 and SCD
LBPM SuperSpeedPlus LFPS Based PWM MessageLBPM is defined as a low power signaling mechanism for two SuperSpeedPlus ports to communicate with each other based on LFPS signals. The adoption of Pulse Width Modulation (PWM) is to embed the transmitting clock in data and to allow for easy data recovery at the receiver based on LFPS clock defined in Table 6-
T二ã€�physical layergen1 8b/10b ç¼–ç �gen2 128b/132b ç¼–ç �gen1 data scramblingSpecial Symbols for Framing and Link ManagementTraining sequence TS1, TS2, TSEQ三ã€�link layer
1 包结�link layer 包结�分为 LMP/TP/DP/ITP header packet 和 data packet payloadLMP TP DP ITP header packetheader packet 包括 link control word�packet headerData Packet Payload
2 link commandsLink commands are used for link level data integrity, flow control and link power management.Link commands are a fixed length of eight symbols and contain repeated symbols to increase the error tolerance. Refer to Section
3 for more details. Link command names have the L-preface to differentiate their link level usage and to avoid confusion with packetsLink Commandb
b
b
b
LGOOD_n0000000HP Sequence Number0000:LGOOD_0…1111:LGOOD_15n: Header Sequence Number.Sent by a port receiving a header packet when all of the following conditions are true:• The header packet has a valid structure and can be recognized by the receiver.• CRC-5 and CRC-16 are valid.• Header Sequence Number in the received header packet matches the expected Rx Header Sequence Number.• An Rx Header Buffer in the receiver is available for storing the received header packet.Mismatch between a Header Sequence Number in the received header packet and the expected Rx Header Sequence Number will result in a port transitioning to Recovery.Received by a port sending a header packet. This is an acknowledgement from a link partnerthat a header packet with the Header Sequence Number of “n� is received properly. Receipt of LGOOD_n mismatching the expected ACK Tx Header Sequence Number will result in a porttransitioning to Recovery.Also sent by a port upon entry to U0 as the Header Sequence Number Advertisement to initialize the ACK Tx HeaderSequence Number of the two ports.LCRD_xLCRD1_xLCRD2_x0001000Gen 1x1, Gen 1x2, Gen 2x1:b3: Reservedb2: Credit series0: LCRD_x or LCRD1_x1: LCRD2_xb1~0: Rx Header Buffer Credit00: LCRD_A/LCRD1_A/LCRD2_A01: LCRD_A/LCRD1_A/LCRD2_A10: LCRD_A/LCRD1_A/LCRD2_A11: LCRD_A/LCRD1_A/LCRD2_Aused to signal the availability of Rx Header Buffers in terms of Credit.LRTY0010000reservedSent by a port before resending the first header packet in response to receipt of LBAD.LBAD0011000reservedBad header packet.Sent by a port receiving the header packet in response to an invalid header packet. Packet that was received has corrupted CRC-5 and/or CRC-
Receipt of LBAD will cause a port to resend all header packets after the last header packet that has been acknowledged with LGOOD_n.Refer to Section
7.
2.
1 for details.LGO_Ux01000000001: LGO_U10010: LGO_U20011: LGO_U3Others: ReservedSent by a port requesting entry to U
Sent by a port requesting entry to U2Sent by a downstream port requesting entry to U
An upstream port shall accept the request.LAU0101000reservedSent by a port accepting the request to enter U1, U2, or U
LXU0110000reservedSent by a port rejecting the request to enter U1 or U
LPMA0111000reservedSent by a port upon receiving L AU. Used in conjunction with LGO_Ux and LAU handshake to guarantee both ports are in the same state.LDN
reservedDownstream port present in U
Sent by a downstream port every 10 µs when there are no packets or other link commands to be transmitted. Refer to Section
7.
5.
1 for detailLUP1001000reservedDevice present in U
Sent by an upstream port every 10 µs when there are no packets or other link commands to be transmitted. Refer to Section
7.
5.