LAN8670/1

Description
Conformity
1 Preface
2 Introduction
3 Pin Description and Configuration
4 Functional Descriptions
5 Register Descriptions
- 5.1 SMI Basic Control and Status Registers
- 5.2 PMA/PMD Registers
- 5.3 PCS Registers
- 5.4 Miscellaneous Registers
  - 5.4.1 Configuration Protection Control
    Configuration Protection Control
  - 5.4.2 Control 1 Register
    Control 1 Register
  - 5.4.3 Control 1 Register - Rev D
    Control 1 Register - Rev D
  - 5.4.4 Pin Control Register
    Pin Control Register
  - 5.4.5 Link Status Control - Rev D
    Link Status Control - Rev D
  - 5.4.6 Status 1 Register
    Status 1 Register
  - 5.4.7 Status 1 Register - Rev D
    Status 1 Register - Rev D
  - 5.4.8 Status 2 Register
    Status 2 Register
  - 5.4.9 Status 2 Register - Rev D
    Status 2 Register - Rev D
  - 5.4.10 Status 3 Register
    Status 3 Register
  - 5.4.11 Interrupt Mask 1 Register
    Interrupt Mask 1 Register
  - 5.4.12 Interrupt Mask 1 Register - Rev D
    Interrupt Mask 1 Register - Rev D
  - 5.4.13 Interrupt Mask 2 Register
    Interrupt Mask 2 Register
  - 5.4.14 Interrupt Mask 2 Register - Rev D
    Interrupt Mask 2 Register - Rev D
  - 5.4.15 Counter Control Register
    Counter Control Register
  - 5.4.16 Transmit Opportunity Count (High)
    Transmit Opportunity Count (High)
  - 5.4.17 Transmit Opportunity Count (Low)
    Transmit Opportunity Count (Low)
  - 5.4.18 BEACON Count (High)
    BEACON Count (High)
  - 5.4.19 BEACON Count (Low)
    BEACON Count (Low)
  - 5.4.20 PLCA Multiple ID 0 Register
    PLCA Multiple ID 0 Register
  - 5.4.21 PLCA Multiple ID 1 Register
    PLCA Multiple ID 1 Register
  - 5.4.22 PLCA Multiple ID 2 Register
    PLCA Multiple ID 2 Register
  - 5.4.23 PLCA Multiple ID 3 Register
    PLCA Multiple ID 3 Register
  - 5.4.24 PLCA Reconciliation Sublayer Control 1
    PLCA Reconciliation Sublayer Control 1
  - 5.4.25 PLCA Reconciliation Sublayer Control 1 - Rev D
    PLCA Reconciliation Sublayer Control 1 - Rev D
  - 5.4.26 PLCA Reconciliation Sublayer Status
    PLCA Reconciliation Sublayer Status
  - 5.4.27 Port Management 2
    Port Management 2
  - 5.4.28 Port Management 2 - Rev D
    Port Management 2 - Rev D
  - 5.4.29 Inactivity Watchdog Timeout (High)
    Inactivity Watchdog Timeout (High)
  - 5.4.30 Inactivity Watchdog Timeout (High) - Rev D
    Inactivity Watchdog Timeout (High) - Rev D
  - 5.4.31 Inactivity Watchdog Timeout (Low)
    Inactivity Watchdog Timeout (Low)
  - 5.4.32 Inactivity Watchdog Timeout (Low) - Rev D
    Inactivity Watchdog Timeout (Low) - Rev D
  - 5.4.33 Transmit Match Control Register
    Transmit Match Control Register
  - 5.4.34 Transmit Match Pattern (High) Register
    Transmit Match Pattern (High) Register
  - 5.4.35 Transmit Match Pattern (Low) Register
    Transmit Match Pattern (Low) Register
  - 5.4.36 Transmit Matched Packet Delay Register
    Transmit Matched Packet Delay Register
  - 5.4.37 Receive Match Control Register
    Receive Match Control Register
  - 5.4.38 Receive Match Pattern (High) Register
    Receive Match Pattern (High) Register
  - 5.4.39 Receive Match Pattern (Low) Register
    Receive Match Pattern (Low) Register
  - 5.4.40 Receive Matched Packet Delay Register
    Receive Matched Packet Delay Register
  - 5.4.41 Credit Based Shaper Stop Threshold (High) Register
    Credit Based Shaper Stop Threshold (High) Register
  - 5.4.42 Credit Based Shaper Stop Threshold (Low) Register
    Credit Based Shaper Stop Threshold (Low) Register
  - 5.4.43 Credit Based Shaper Start Threshold (High) Register
    Credit Based Shaper Start Threshold (High) Register
  - 5.4.44 Credit Based Shaper Start Threshold (Low) Register
    Credit Based Shaper Start Threshold (Low) Register
  - 5.4.45 Credit Based Shaper Slope Control Register
    Credit Based Shaper Slope Control Register
  - 5.4.46 Credit Based Shaper Top Limit (High) Register
    Credit Based Shaper Top Limit (High) Register
  - 5.4.47 Credit Based Shaper Top Limit (Low) Register
    Credit Based Shaper Top Limit (Low) Register
  - 5.4.48 Credit Based Shaper Bottom Limit (High) Register
    Credit Based Shaper Bottom Limit (High) Register
  - 5.4.49 Credit Based Shaper Bottom Limit (Low) Register
    Credit Based Shaper Bottom Limit (Low) Register
  - 5.4.50 Credit Based Shaper Credit Counter (High) Register
    Credit Based Shaper Credit Counter (High) Register
  - 5.4.51 Credit Based Shaper Credit Counter (Low) Register
    Credit Based Shaper Credit Counter (Low) Register
  - 5.4.52 Credit Based Shaper Control Register
    Credit Based Shaper Control Register
  - 5.4.53 PLCA Skip Control Register
    PLCA Skip Control Register
  - 5.4.54 PLCA Transmit Opportunity Skip Register
    PLCA Transmit Opportunity Skip Register
  - 5.4.55 Application Controlled Media Access Control Register
    Application Controlled Media Access Control Register
  - 5.4.56 Sleep Control 0 Register
    Sleep Control 0 Register
  - 5.4.57 Sleep Control 0 Register - Rev D
    Sleep Control 0 Register - Rev D
  - 5.4.58 Sleep Control 1 Register
    Sleep Control 1 Register
  - 5.4.59 Sleep Control 1 Register - Rev D
    Sleep Control 1 Register - Rev D
  - 5.4.60 Collision Detector Control 0 Register
    Collision Detector Control 0 Register
  - 5.4.61 Collision Detector Control 0 Register - Rev D
    Collision Detector Control 0 Register - Rev D
  - 5.4.62 SQI Control Register
    SQI Control Register
  - 5.4.63 SQI Control Register - Rev D
    SQI Control Register - Rev D
  - 5.4.64 SQI Status 0 Register
    SQI Status 0 Register
  - 5.4.65 SQI Status 0 Register - Rev D
    SQI Status 0 Register - Rev D
  - 5.4.66 SQI Configuration 0 Register
    SQI Configuration 0 Register
  - 5.4.67 SQI Configuration 0 Register - Rev D
    SQI Configuration 0 Register - Rev D
  - 5.4.68 SQI Configuration 2 Register
    SQI Configuration 2 Register
  - 5.4.69 SQI Configuration 2 Register - Rev D
    SQI Configuration 2 Register - Rev D
  - 5.4.70 Pad Control 3 Register
    Pad Control 3 Register
  - 5.4.71 Analog Control 5
    Analog Control 5
  - 5.4.72 OPEN Alliance Map ID and Version Register
    OPEN Alliance Map ID and Version Register
  - 5.4.73 OPEN Alliance Map ID and Version Register - Rev D
    OPEN Alliance Map ID and Version Register - Rev D
  - 5.4.74 PLCA Control 0 Register
    PLCA Control 0 Register
  - 5.4.75 PLCA Control 1 Register
    PLCA Control 1 Register
  - 5.4.76 PLCA Status Register
    PLCA Status Register
  - 5.4.77 PLCA Transmit Opportunity Timer Register
    PLCA Transmit Opportunity Timer Register
  - 5.4.78 PLCA Burst Mode Register
    PLCA Burst Mode Register
  - 5.4.79 PLCA Diagnostics Register - Rev D
    PLCA Diagnostics Register - Rev D
  - 5.4.80 Advanced Diagnostic Features Capability - Rev D
    Advanced Diagnostic Features Capability - Rev D
  - 5.4.81 Harness Defect Detection - Rev D
    Harness Defect Detection - Rev D
  - 5.4.82 Dynamic Channel Quality Transmit Opportunity ID Register - Rev D
    Dynamic Channel Quality Transmit Opportunity ID Register - Rev D
  - 5.4.83 Signal Quality Index Register - Rev D
    Signal Quality Index Register - Rev D
  - 5.4.84 Signal Quality Index Plus Register - Rev D
    Signal Quality Index Plus Register - Rev D
  - 5.4.85 Topology Discovery Control Register - Rev D
    Topology Discovery Control Register - Rev D
  - 5.4.86 Topology Discovery Status Register - Rev D
    Topology Discovery Status Register - Rev D
  - 5.4.87 Topology Discovery Distance measurement Result Register (Low) - Rev D
    Topology Discovery Distance measurement Result Register (Low) - Rev D
  - 5.4.88 Topology Discovery Distance measurement Result Register (High) - Rev D
    Topology Discovery Distance measurement Result Register (High) - Rev D
  - 5.4.89 Topology Discovery Internal Delay Result Register (Low) - Rev D
    Topology Discovery Internal Delay Result Register (Low) - Rev D
  - 5.4.90 Topology Discovery Internal Delay Result Register (High) - Rev D
    Topology Discovery Internal Delay Result Register (High) - Rev D
  - 5.4.91 Topology Discovery Measured Node Delay measurement Result Register (Low) - Rev D
    Topology Discovery Measured Node Delay measurement Result Register (Low) - Rev D
  - 5.4.92 Topology Discovery Measured Node Delay measurement Result Register (High) - Rev D
    Topology Discovery Measured Node Delay measurement Result Register (High) - Rev D
  - 5.4.93 Topology Discovery Measured Node Measurement Duration Register - Rev D
    Topology Discovery Measured Node Measurement Duration Register - Rev D
  - 5.4.94 Topology Discovery Advanced Control Register - Rev D
    Topology Discovery Advanced Control Register - Rev D
  - 5.4.95 Wake Sleep Status Register - Rev D
    Wake Sleep Status Register - Rev D
  - 5.4.96 Wake Sleep Control Register
    Wake Sleep Control Register
6 Application Information
7 Operational Characteristics
8 Packaging Information
9 Package Marking Information
Product Identification System
Data Sheet Revision History
Microchip Information

5.4.77 PLCA Transmit Opportunity Timer Register

Name:	PLCA_TOTMR
Address:	0xCA04


Bit	15	14	13	12	11	10	9	8

Access	RO	RO	RO	RO	RO	RO	RO	RO
Reset	0	0	0	0	0	0	0	0


Bit	7	6	5	4	3	2	1	0
	TOTMR[7:0]
Access	R/W	R/W	R/W	R/W	R/W	R/W	R/W	R/W
Reset	0	0	1	0	0	0	0	0

Bits 7:0 – TOTMR[7:0] PLCA Transmit Opportunity Timer

Configures the PLCA Transmit Opportunity time allowed for each node to begin transmitting and capture the carrier sense for all nodes on the network. The time is represented in increments of 100 ns (i.e., 1 BT). This field defaults to 32 bit times (3.2 μs) according to the IEEE Std 802.3-2022 specification (Clause 30.16.1.1.5), and the OPEN Alliance 10BASE‑T1S PLCA Management Registers Specification, Version 1.2.

Important: This field must be configured identically across all nodes on the multidrop mixing segment.

CAUTION: Improper configuration of Transmit Opportunity timer may result in reduced network performance or collisions. Determination of the optimal Transmit Opportunity time requires knowledge of various delays of each of the vendor PHYs on the mixing segment and various physical layer propagation delay. It is recommended to leave this field at its default value unless a full evaluation of delays has been performed.

Note: Due to discrepancies in the default value for this register between Version 1.0 of the OPEN Alliance 10BASE‑T1S PLCA Management Registers Specification for this field and Clause 30.16.1.1.5 of the IEEE Std 802.3‑2022 specification, it is recommended that this field always be configured to the desired value for all Microchip and non-Microchip devices on the network.

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