Backchannel protocol for link training and adaptation
View Patent ↗An electronic device includes circuitry configured to establish a steady-state connection with another device via a communication link. A backchannel data frame is detected in a steady-state data stream received from the other device via the communication link at a first predetermined data rate. The circuitry is configured to modify one or more signal transmission parameters based on signal information included in the backchannel data frame.
1. An electronic device comprising:
circuitry configured to
establish a steady-state connection with another device via a communication link,
detect a backchannel data frame in a steady-state data stream received from the another device via the communication link at a first predetermined data rate, and
modify one or more signal transmission parameters based on signal information included in the backchannel data frame,
wherein the circuitry is further configured to detect a locking data frame received from the another device at a second predetermined data rate that includes a predetermined locking data word.
2. The device of claim 1 , wherein the electronic device and the another device are serializer/deserializer (SERDES) devices.
3. The device of claim 1 , wherein the backchannel data frame includes at least one of one or more error correction code (FCC) bits, a frame inversion bit, or one or more signal information words.
4. The device of claim 3 , wherein the one or more signal information words include at least one of a control data word indicating one or more modified signal transmission parameters or a status data word indicating a current status of the another device.
5. The device of claim 1 , wherein the circuitry is further configured to detect the locking data frame in a case that a received data frame has a number of detected errors that is less than a predetermined threshold and one or more received bits of the received data frame correspond to the predetermined locking data word.
6. The device of claim 5 , wherein the circuitry is further configured to set a frame lock condition in a case that the number of consecutively detected locking data frames is greater than a predetermined threshold.
7. The device of claim 6 , wherein the circuitry is further configured to output a frame lock interrupt to the another device via the communication link in response to setting the frame lock condition.
8. The device of claim 6 , wherein the circuitry is further configured to detect the backchannel data frame at the first predetermined data rate in response to setting the frame lock condition.
9. The device of claim 1 , wherein the second predetermined data rate is greater than the first predetermined data rate.
10. The device of claim 1 , wherein the first predetermined data rate is based on at least one of an amount of variability of one or more communication link parameters or a transmission data bandwidth of the communication link.
11. The device of claim 1 , wherein the circuitry is further configured to determine that an out of lock (OOL) condition exists in a case that a number of consecutively received backchannel data frames that fail an ECC check is greater than a predetermined threshold.
12. The device of claim 11 , wherein the circuitry is further configured to output a reframing interrupt signal to the another device in the case that the OOL condition exists.
13. The device of claim 1 , wherein the circuitry is further configured to invert one or more bits of the backchannel data frame in a case that a frame inversion bit is equal to one.
14. The device of claim 1 , wherein the circuitry is further configured to determine one or more modified signal transmission parameters from a most significant data word or a least significant data word of the backchannel data frame.
15. The device of claim 14 , wherein the circuitry is further configured to modify one or more finite impulse response (FIR) filter taps of the device based on the modified signal transmission parameters.
16. The device of claim 14 , wherein the one or more modified signal transmission parameters correspond to duty cycle distortion (DCD) or digital-to-analog converter (DAC) skew correction parameters.
17. The device of claim 14 , wherein the circuitry is further configured to output a backchannel response to the another device via the communication link when a number of the backchannel data frames with corresponding signal transmission parameters is greater than a predetermined threshold.
18. A method comprising:
establishing, at an electronic device with circuitry, a steady-state connection with another device via a communication link;
detecting, via the circuitry, a backchannel data frame in a steady-state data stream received from the another device via the communication link at a first predetermined data rate; and
modifying, via the circuitry, one or more signal transmission parameters of a transmitter included in the electronic device based on signal information included in the backchannel data frame,
wherein the method further includes detecting a locking data frame received from the another device at a second predetermined data rate that includes a predetermined locking data word.
19. An electronic device comprising:
circuitry configured to
establish a steady-state connection with another device via an Ethernet communication link,
extract one or more modified signal transmission parameters from a detected backchannel data frame in a data stream received from the another device via the Ethernet communication link, and
modify one or more signal processing parameters of an Ethernet transmitter included in the electronic device based on the one or more modified signal transmission parameters included in the backchannel data frame,
wherein the circuitry is further configured to detect a locking data frame received from the another device at a second predetermined data rate that includes a predetermined locking data word.