| 摘要 |
PURPOSE: A control unit is provided to enable a designer to easily find or modify design errors, and to easily change the design by applying a micro-program control technique in implementing a hard-wired control. CONSTITUTION: The unit comprises a control logic generator(610), a decoder(620), and a timing generator(630). The control logic generator(610) stores instructions from an instruction register(600) and controls the decoder(620). The decoder(620) generates and decodes a final control signal for controlling a processor. The timing generator(630) implements time steps with a proper size under a control of process time step by the decoder(620). The control logic generator(610), corresponding to a ROM, is implemented by standard cells so it can overcome the speed and area limit of the ROM or a PLA(programmable Logic Array). The binary file of the control logic generator(610) is similar to a ROM file generated in a micro-program control method. One control word comprises a plurality of fields, and the fields not used in a current micro-operation have basic values corresponding to no operation. The timing generator(630) is basically implemented by a ring counter. The time-step can be extended according to the process time of the instructions and specific time-steps are repeated.
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