The MP7543 consists of two 12-bit registers, control logic and a 12-bit multiplying D/A converter. The input register (register A) is a 12-bit serial-in parallel-out shift register. Serial data at the SR1 pin is clocked into Register A on the leading or trailing edge (user selected) of the strobe input, with the MSB loaded first. Register B is a 12-bit parallel-in parallel-out register that follows register A. The contents of register A are loaded into register B