Design of an 8 bit general purpose microcontroller with sea-of-gates design style

This study includes the VLSI design of an eight bit general purpose microcontroller with sea-of-gates design style and 1.6 μm double metal CMOS technology. The system blocks and the behaviour of these blocks are defined and the logical design is implemented at gate level in the design phase. Then, the logic circuits are simulated and all of the subunits are converted into VLSI layout with Ocean Design System, prepared by Delft University-Netherlands, in a PC using the Linux operating system. Finally, in order to construct the microcontroller, these units are placed in the floorplan and simulated with analog and digital, logic and switch level simulators. The results of the simulations indicate that the microcontroller can run 31 instructions which can be divided into six sub-groups: transfer instructions, arithmetic and logic instructions, rotate and shift instructions, branch instructions, input/output instructions, and control instructions. The external microcontroller bus is 16 bit. It includes approximately 10,000 transistors and runs at 25 MHz. Its power consumption is 82.5 mW for 5 V bias voltage. In this paper, the properties of the microcontroller, the design steps and the obtained results are explained.