Difference between revisions of "Simple SoC"

Revision as of 22:13, 29 March 2015

Description

A very basic, custom SoC softcore

Primary git repo: on github

Specs/Design: on github as well

We'll merely keep a meetup log and notes here, important stuff will be stored in One Single Repo (tm), next to the code :)

(Final?) working implementation, with VGA output and debugger

https://www.youtube.com/watch?v=YfNVco7CpEU

Meetup Log

2013/09/11 - September reunion

• Discuss and improve specs a bit
• Update documentation and C# ref. implementation
• forked from Programmable Logic Lessons to Simple SoC

2013/09/18 - Let there be code

• Debugged & Finished sdlcore implementation

2013/09/25 - Verilog at last

• Spec now has vsync
• Reviewed sdlcore code
• Hacked together some very basic Verilog

2013/10/02 - Howdy Simulator

• Implemented ram
• Added delays for ram

2013/10/09 - Howdy Simulator, for real

• debug, debug, debug, and simulate
• Implemented more state logic
• cpu mostly works, needs some more opcodes!

2013/10/16 - How about conditions?

• Implemented beq, bga, bgt, jr, draw, fixed write16, read16
• wired up vram (resized to 2bpp because it doesn't fit)
• added vga output, but it is glitched/buggy

2013/10/23 - We love glitches

• Fixed VGA, centered image, still outputs corrupted data though
• vram resized to 256x256x3 in order to fit

2013/10/30 - Corrupted Pixels

• Had no luck actually locating the vga corruption bug
• simulator results and simpler test cases seem to work fine
• implemented wait

2013/11/13 - Differential debugging

• Investigate serial communications
• Try out UART sample
• draft out ICE spec

2013/11/20 - Want some ICE?

• *almost* implemented the UART
• We have some pin collisions on clock vs dcm vs io-standards per ban

2013/12/04 - Clocks and IO

• Worked around the IO/DCM issues
• WIP on the ICE implementation

2013/12/11 - Debuggable Hardware

• Work on the ICE implementation

2014/01/22 - ICEful modules

• Modularization, refactoring

2014/01/29 - Making it work once more

• Get the modularised code back into working state
• implement some of the ICE state machine

2014/02/05 - Debugger Integration

• implement some of the ICE state machine
• have it talk nicely with the debugger
• -> We got VGA writes working!

2014/02/26 - Wait States

• Add wait states for ICE & module integration on the cpu
• have it talk nicely with the debugger

Resources

• The material from Programmable Logic Lessons
  • Direct links, slides, vga_out verilog example, a simple cpu in C
• Your favorite search engine