Subversion Repositories mcs-4

Last modification

• Rev 6, 2021-12-02 21:58:25 GMT
• Author: rrpollack

• Log message:

  Massive update of all MCS-4 components
  
  This commit updates all the previous i4004 CPU modules to address
  various bugs that were found during testing. At this point, all
  CPU functions appear to operate correctly. No FPGA-specific
  features are required by the i4004 CPU implementation.
  
  This commit also provides implementations of the 4001 ROM, 4002 RAM,
  and 4003 Shift Register chips, thus allowing a functional MCS-4
  system to be implemented. Some of these modules are dependent on
  features found in the Xilinx Spartan FPGA, such as Block RAM and
  dual-port Distributed RAM, though alternate implementations are
  possible for other FPGAs.
  
  These modules have been used (along with keyboard and printer emulation
  modules not provided here) to implement a complete Busicom 141-PF calculator
  clone using a Xilinx Spartan 6 FPGA and a custom PCB. All functions
  of the Busicom 141-PF calculator appear to function normally.