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US 12,602,335 B2Granted
Memory interface with reduced energy transmit mode
AssigneeNVIDIA Corporation
InventorsJames Michael O'Connor, Donghyuk Lee
Life of this patent
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Abstract
PAM encoding techniques that leverage unused idle periods in channels between data transmissions to apply longer but more energy-efficient codes. To improve energy savings, multiple sparse encoding schemes may be utilized selectively to fit different sized gaps in the traffic. These approaches may provide energy reductions, for example with memory READ and WRITE traffic, when transferring 4-bit data using 3-symbol sequences.
Claims22
A communication method comprising:
- applying a first encoding technique on a bit sequence to generate a plurality of first pulse amplitude modulated (PAM) symbols for data communicated over at least one bus;
- detecting a gap in command traffic on the bus;
- and
- in response to detecting the gap in command traffic, switching to a second encoding technique on the bit sequence to generate second PAM symbols for the data on the bus in the gap, the second PAM symbols comprising higher sparsity than the first PAM symbols.
1 more element
A transceiver comprising:
- a first codebook for a plurality of first PAM symbols;
- a second codebook for a second plurality of PAM symbols comprising higher sparsity than the first PAM symbols;
- and
- logic to switch from the first codebook to the second codebook to generate symbols on a data bus, in response to detection of a gap in command traffic, the symbols generated in the gap.
1 more element
A system comprising:
- a processor;
- a memory;
- logic to switch from utilizing a first encoding mechanism to utilizing a second encoding mechanism to generate PAM symbols on a memory bus, in response to detection of a gap in access commands from the processor to the memory, the symbols generated in the gap;
- and
- wherein the second encoding mechanism draws less power from the memory bus than the first encoding mechanism.
2 more elements
A communication method comprising:
- applying a first encoding technique on a bit sequence to generate a plurality of first pulse amplitude modulated (PAM) symbols for data communicated over at least one bus;
- detecting a gap in command traffic on the bus;
- in response to detecting the gap in command traffic, switching to a second encoding technique on the bit sequence to generate second PAM symbols for the data on the bus in the gap, the second PAM symbols comprising higher sparsity than the first PAM symbols;
- and
- on condition that a first symbol value is not a lowest-energy consumption symbol value, swapping the first symbol value on the bus with a second symbol value of lowest energy consumption;
- and
- encoding an indication of the swap on a data bus inversion (DBI) line of the at least one bus.
4 more elements
A communication method comprising:
- applying a first encoding technique on a bit sequence to generate a plurality of first pulse amplitude modulated (PAM) symbols for data communicated over at least one bus;
- detecting a gap in command traffic on the bus;
- in response to detecting the gap in command traffic, switching to a second encoding technique on the bit sequence to generate second PAM symbols for the data on the bus in the gap, the second PAM symbols comprising higher sparsity than the first PAM symbols;
- and
- on condition that one of the first PAM symbols or one of the second PAM symbols, respectively, is a highest energy consumption symbol, shifting a level of a next symbol to transmit on the bus to a next highest level than the first encoding technique or the second encoding technique, respectively, would have generated otherwise.
2 more elements
Dependencies are inferred from the claim text.