Vector signaling codes with high pin-efficiency for chip-to-chip communication and storage

An alternative type of vector signaling codes having increased pin-efficiency normal vector signaling codes is described. Receivers for these Permutation Modulation codes of Type II use comparators requiring at most one fixed reference voltage. The resulting systems can allow for a better immunity to ISI-noise than those using conventional multilevel signaling such as PAM-X. These codes are also particularly advantageous for storage and recovery of information in memory, as in a DRAM.