====== 6502 simulator ======

===== Purpose =====
This project is primarily an exercise to prepare for a more in-depth project. Inspired by modern [[:histcomp:Apple II]] expansion cards like the V2 Retro Computing Analog card [(https://www.v2retrocomputing.com/analog)], we wish to design a microcontroller-based card for future experimentation, the eventual goal being an emulated Z80 softcard. We know this is an achievable goal, but it seems prudent to try writing a PC-based CPU simulator first. We have selected the [[:histcomp:6502]] as our target for its low instruction count, simple architecture, and variety of addressing modes. 

Our goals are as follows:

  - a SIMH-like console interface with memory/register editing, breakpoints, disassembler, and single-step execution
  - simulated RAM, ROM, and I/O devices with memory mapping and bank switching
  - realistic timing
  - a portable and general core
  - extensible for future GPIO operation

This is **not** intended to be able to simulate a full Apple II, NES, or similar 6502-based device. 

===== Design =====
==== CPU core ====
  * registers
  * fetch-decode loop
  * hold states and breakpoints

==== Simulator console and debugger ====
  * commands
  * breakpoint management
  * limitations
  * I/O devices

===== Evaluation =====

===== Notes =====
[(6502pm>[[https://web.archive.org/web/20221112220344if_/http://archive.6502.org/datasheets/synertek_programming_manual.pdf|6502 Programmer's Manual]])]

~~REFNOTES~~