Editing Control unit (section)

== Microprogram control unit ==
{{main|Microcode}}

The idea of microprogramming was introduced by [[Maurice Wilkes]] in 1951 as an intermediate level to execute [[computer program]] instructions. Microprograms were organized as a sequence of ''microinstructions'' and stored in special control memory. The algorithm for the microprogram control unit, unlike the hardwired control unit, is usually specified by [[flowchart]] description.<ref>{{Cite book  | last1 = Barkalov | first1 = Alexander | title = Logic synthesis for FSM based control units / Alexander Barkalov and Larysa Titarenko | year = 2009 | publisher = Springer | location = Berlin | isbn = 978-3-642-04308-6 }}</ref> The main advantage of a microprogrammed control unit is the simplicity of its structure. Outputs from the controller are by microinstructions. The microprogram can be debugged and replaced similarly to software.<ref>{{Cite book  | last1 = Wiśniewski | first1 = Remigiusz | title = Synthesis of compositional microprogram control units for programmable devices   | year = 2009 | publisher = University of Zielona Góra | location = Zielona Góra | isbn = 978-83-7481-293-1 | pages = 153}}</ref>