Control Units Basic Ideas Logically, it appears simple. In reality it is a little more complicated. Take Add AX b as an example. In executing this instruction, the CPU would have to do the following. For each instruction in the instruction set, there is such a sequence corresponding to it.
Conventional unit uses hard-wired control units.
Microprogrammed control unit places a sequence of command, or micro-instructions in ROM for each instruction. We will study micro-programmed control unit here. For each of the instructions, the following would happen in the control unit.