Fig. 5: Order Code Processor (OCP).
From: Malodour classification with low-cost flexible electronics

The components in OCP (digital SRI block) are shown. OCP supports 16 different instructions. There are three registers each of which has a 5-bit width. The fixed code sits in the programme memory where each instruction is microcoded in the microcode memory. The programme and microcode memory sizes are 256 and 832 bits, respectively.