Error detection pin encoding scheme to avoid maximum transitions and further improve signal integrity on high speed graphic memory interfaces

A method comprising:

• encoding seven bits of a first eight-bit data value as a first set of four PAM-4 symbols on a first serial data line;
• encoding seven bits of a second eight-bit data value as a second set of four PAM-4 symbols on the first serial data line;
• and
• encoding one bit of the first eight-bit data value and one bit of the second eight-bit data value that were not encoded in the first set of four PAM-4 symbols and the second set of four PAM-4 symbols, respectively, as a first PAM-4 symbol on a second serial data line;
• encoding error correction bits for the first eight-bit data value and the second eight-bit data value as PAM-4 symbols on a channel dedicated to communicating error correction bits;
• and
• encoding one bit of a third eight-bit data value as a (+1, −1) symbol on the channel dedicated to communicating error correction bits.

A system comprising:

• a transmitter;
• a receiver;
• a bus coupling the the transmitter to the receiver, the bus comprising:
• at least one set of eight parallel data channels;
• an auxiliary data channel per each set of eight parallel data channels;
• and
• an error correction channel per each set of eight parallel data channels;
• and
• logic configured to communicate every 8th bit of data from seven of the eight parallel data channels in a 32-bit data burst on the auxiliary data channel and to communicate every 8th bit of data from an eighth parallel data channel on the error correction channel.

A method comprising:

• in a system comprising a data bus comprising at least one set of eight parallel data channels, an auxiliary data channel per each set of eight parallel data channels, and an error correction channel per each set of eight parallel data channels:
• communicating every 8th bit of data from seven of the eight parallel data channels in a 32-bit data burst on the auxiliary data channel;
• and
• communicating every 8th bit of data from an eighth parallel data channel on the error correction channel.