Low latency multi-level communication interface
First Claim
1. A multi-mode pulse-amplitude-modulation (PAM) receiver for receiving a sequence of symbols, the receiver comprising:
- a receiver circuit configured to receive the sequence of symbols; and
logic circuitry coupled to the receiver circuit;
wherein the multi-mode PAM receiver is capable of operating in a specified mode of a plurality of predefined modes;
wherein the received symbols are N-PAM symbols when the specified mode is a first mode, each respective N-PAM symbol in the sequence of received symbols having one of N distinct symbol values;
wherein the received symbols are M-PAM symbols when the specified mode is a second mode, each respective M-PAM symbol in the sequence of received symbols having one of M distinct symbol values; and
wherein N is not equal to M.
1 Assignment
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Accused Products
Abstract
A memory system uses multiple pulse amplitude modulation (multi-PAM) output drivers and receivers to send and receive multi-PAM sigsnals. A multi-PAM signal has more than two voltage levels, with each data interval now transmitting a “symbol” at one of the valid voltage levels. In one embodiment, a symbol represents two or more bits. The multi-PAM output driver drives an output symbol onto a signal line. The output symbol represents at least two bits that include a most significant bit (MSB) and a least significant bit (LSB). The multi-PAM receiver receives the output symbol from the signal line and determines the MSB and the LSB.
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Citations
37 Claims
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1. A multi-mode pulse-amplitude-modulation (PAM) receiver for receiving a sequence of symbols, the receiver comprising:
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a receiver circuit configured to receive the sequence of symbols; and logic circuitry coupled to the receiver circuit; wherein the multi-mode PAM receiver is capable of operating in a specified mode of a plurality of predefined modes; wherein the received symbols are N-PAM symbols when the specified mode is a first mode, each respective N-PAM symbol in the sequence of received symbols having one of N distinct symbol values; wherein the received symbols are M-PAM symbols when the specified mode is a second mode, each respective M-PAM symbol in the sequence of received symbols having one of M distinct symbol values; and wherein N is not equal to M. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A multi-mode pulse-amplitude-modulation(PAM) transceiver comprising:
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a multi-mode PAM output driver, configured to output a first stream of signals at a symbol rate on a first signal path; and a multi-mode PAM receiver, configured to receive a second stream of signals at the symbol rate from a second signal path; wherein the first stream of signals includes a sequence of N-PAM symbols when a mode signal is in a first mode signal state, each respective N-PAM symbol in the sequence of N-PAM symbols having one of N distinct symbol values; wherein the first stream of signals includes a sequence of M-PAM symbols when the mode signal is in a second mode signal state, each respective M-PAM symbol in the sequence of M-PAM symbols having one of N distinct symbol values; and where N is not equal to M, and wherein symbols in a respective mode in the plurality of predefined modes include two or more voltage levels. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37)
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Specification