8051 Core

Description

One of the best supported and most widely used types of embedded CPUs is Intel‘s MCS 51 series of devices. This is enough reason to create an 8051-compatible CPU core for FPGA usage. Use of this core makes very much sense when porting existing designs to FPGA technology, or as an easy-to-adapt reference application.

Features

  • cycle compatible to MCS 51
    • supported by a wide range of development tools
  • very compact design
    • on-chip 128 byte data RAM
    • minimum gate count
    • optimized for FPGA implementation
  • lowest possible design risk
    • free behavioral model
    • comprehensive reference application
    • synthesizable VHDL model
  • very low cost

Synthesis

The core was successfully synthesized with Synopsys FPGA Express and Xilinx XST. This is a summary of the required resources:

  • total number of 4 input LUTs: 1,934
    • number used as LUTs: 1,846
    • number used as route-thru: 24
    • number used as 32×1 RAMs: 64
  • number of slice flip flops: 353
  • total equivalent gate count: 23,299

Verification

The CPU core was verified on several levels:

  • simulation of every single instruction
  • simulation of test programs
  • real-life test with reference applications