Design and Implementation of the Control Parallel Port of the Model Machine

Microprogramming control model machine is to program control signals into microinstructions and store into ROM.When the machine runs,these microinstructions are read one by one and the control signals are produced correspondingly.To improve the construct and performance of the basic model machine,through data path of the model machine controlled by micro program parallel,the authors designed port commands of reading and writing to control 8255 chip.Firstly,designed the instruction set of the model mac-hine.Secondly,gave the electric circuit to realize the function of parallel port.Finally,the whole model machine were formed.Then the model structure is more perfect and the function of model machine is enlarged.