Energy efficient ethernet with multiple low-power modes
An Ethernet transceiver is disclosed. The Ethernet transceiver includes transceiver circuitry including transmit circuitry, receive circuitry, and adaptive filters. The transceiver circuitry is configurable to operate in one of two low-power modes. A first low-power mode includes update operations for the adaptive filters. A second low-power mode includes turning off at least one of the transmit circuitry and the receive circuitry, and omitting update operations for the adaptive filters.
1. An Ethernet transceiver, comprising:
transceiver circuitry including transmit circuitry, receive circuitry, and adaptive filters;
wherein the transceiver circuitry is configurable to operate in one of two low-power modes, including
a first low-power mode including update operations for the adaptive filters, and
a second low-power mode including turning off at least one of the transmit circuitry and the receive circuitry, and omitting update operations for the adaptive filters.
2. The Ethernet transceiver of claim 1 , wherein:
the update operations involve transferring refresh symbols.
3. The Ethernet transceiver of claim 1 , wherein:
the transceiver circuitry is configurable as one of a master device and a slave device, and
wherein operation in the second low-power mode for a master device is different than for a slave device.
4. The Ethernet transceiver of claim 3 , wherein:
with the transceiver circuitry configured as a master device in the second low-power mode
the receive circuitry is operative to periodically monitor for an alert symbol transferred from a slave link partner.
5. The Ethernet transceiver of claim 4 , wherein:
the receive circuitry is operative to periodically monitor for an alert symbol based on an LDPC frame timing boundary.
6. The Ethernet transceiver of claim 3 , wherein:
with the transceiver circuitry configured as a slave device in the second low-power mode
the transmit circuitry is operative to transfer an alert symbol to a master link partner upon waking to transfer data.
7. The Ethernet transceiver of claim 6 , wherein:
the transmit circuitry is operative to transfer an alert symbol to a master link partner based on an LDPC frame timing boundary.
8. An Ethernet network, comprising:
a network hub including multiple Ethernet ports;
multiple network devices coupled to the multiple Ethernet ports via multiple Ethernet data links;
wherein each of the multiple Ethernet data links includes an upstream path for transferring data from the network hub to a given network device, and a downstream path for transferring data from the given network device to the network hub; and
wherein each of the Ethernet data links is configurable to operate in one of two low-power modes, including
a first low-power mode including powering down unused transceiver circuitry and performing filter update operations on the link, and
a second low-power mode including powering down unused transceiver circuitry, and omitting filter update operations on the link.
9. The Ethernet network of claim 8 , wherein:
solely the upstream path for each Ethernet data link operates in the second low-power mode.
10. The Ethernet network of claim 8 , wherein:
the multiple network devices comprise at least one from the group including a sensor, video camera or telematics data monitoring device.
11. The Ethernet network of claim 10 , wherein:
the network hub and the multiple network devices are disposed within the body of a motor vehicle.
12. The Ethernet network of claim 11 , wherein:
the multiple network devices generate data for use in an autonomous driving system.
13. A method of operation for an NBASE-T Ethernet transceiver, comprising:
providing transceiver circuitry including transmit circuitry, receive circuitry, and adaptive filters; and
configuring the transceiver circuitry to operate in one of two low-power modes, including
a first low-power mode including updating the adaptive filters, and
a second low-power mode including turning off at least one of a transmit circuit and a receive circuit, and omitting update operations for the adaptive filters.
14. The method of claim 13 , wherein:
the updating includes transferring refresh symbols having filter coefficient information.
15. The method of claim 13 , further comprising:
configuring the transceiver circuitry as one of a master device and a slave device, and
wherein operation in the second low-power mode for a master device is different than for a slave device.
16. The method of claim 15 , wherein:
with the transceiver circuitry configured as a master device in the second low-power mode,
periodically monitoring for an alert symbol transferred from a slave link partner.
17. The method of claim 16 , wherein:
the periodically monitoring is based on an Ethernet data frame timing boundary.
18. The method of claim 15 , wherein:
with the transceiver circuitry configured as a slave device in the second low-power mode
transferring an alert symbol to a master link partner upon waking to transfer data.
19. The method of claim 18 , wherein:
the transferring is based on an LDPC frame timing boundary.
20. The method of claim 19 , further comprising:
after transferring the alert symbol, performing a training operation with the master link partner.