Circuit diagram for alu is illustrated in figure 57

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Unformatted text preview: U is illustrated in Figure 5.7 and the design code is also given in Appendix F. Figure 5.7: ALU Module’s Circuit Design. 5.4-4. DECODER The CPU core has the 2to4 decoder for the 2-Bit valued signals Rx and Ry, which are generated by the Control Unit from the decoded 16-Bit instruction. With the help of 2to4 decoder we can select four different registers with the 2-Bit value of 66 either Rx or Ry. Therefore four registers are selected by the 2-Bits of Rx and next four registers are selected by the 2-Bits of Ry. Circuit diagram for Decoder is illustrated in Figure 5.8 and the design code is also given in Appendix F. Figure 5.8: Decoder Module’s circuit representation. 5.4-5. PROGRAM COUNTER The program counter controls the execution sequence of instructions. After an instruction is executed, program counter is incremented by one value. When microprocessor is resetted, the default value of program counter is loaded i.e. zero. Circuit diagram for Program Counter is illustrated in Figure 5.9 and the design code is also given in Appendix F. 67 Figure 5.9: Program Counter Module’s Circuit Representation. 5.4-6. M ACHINE CYCLE COUNTER The Machine Cycle Counter is a simple 2-Bit up counter and provides the necessary timing for the instruction execution in the control unit. Also we can say that it counts the number of machine cycles consumed by a single instruction. Circuit diagram for Machine Cycle Counter is illustrated in Figure 5.10 and the design code is also given in Appendix F. Figure 5.10: Machine Cycle Counter Module’s Circuit Representation. 68 5.4-7. REGISTER The Register module is an 8-Bit Verilog construct by which several registers can be instantiated. The current processor core utilizes six 8-Bit registers but several others can also be created if required. Registers act as temporary storage for data under processing. Circuit diagram for Register is illustrated in Figure 5.11 and the design code is also given in Appendix F. Figure 5.11: Register Module’s...
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This note was uploaded on 01/19/2014 for the course ECE 5101 taught by Professor Sass during the Spring '14 term at UNC Charlotte.

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