The Curious Engineer

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Making a C64/C65 compatible computer

c65gs.blogspot.com

Commodore 8-bitFPGA / HDLRetro computingEmbedded / microcontrollers

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431 from 24 Jan 2014 to 17 Oct 2026
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monthly (13 in the last year)
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2026 7

  1. SSNAIL: A local LLM processor for the MEGA65: First light (well, tokens)
  2. MEGAphone: Integrating it all into a working package
  3. MEGAphone / Rugged MEGA65 Wiring Loom
  4. MEGA65 Multiverse Bitstream Loader
  5. MEGAphone Hardware Module Progress Update
  6. MEGAphone: Cellular Modem Voice Circuit Control
  7. MEGAphone Cellular Modem and Power Control Hook-up for R3 Boards and Phone Call Handling

2025 33

  1. MEGAphone Cellular Modem Communications: SMS Messaging
  2. MEGAphone User Interface and Text Messaging Software
  3. MEGAphone Power Management FPGA and Software Interface
  4. MEGAphone Contact list and Dialer Integration
  5. MEGAphone Case Design
  6. MEGAphone contact list and Dialer
  7. SMS Thread Display, Message Editing etc
  8. Simple Memory Protection Scheme
  9. Stack backtrace on MEGA65 using MOS-LLVM
  10. Unicode / TrueType Pre-Rendered Fonts for the MEGA65
  11. Auto-detecting SCART/15KHz Cables
  12. SCART/VGA 15KHz output and NTSC Colour Space Fixes
  13. MEGAphone Module Building Progress: Cellular modem and DC:DC modules
  14. MEGAphone FPGA board carrier modules
  15. MEGAphone software tools and laying the foundation
  16. MEGAphone Call, SMS and Contacts Management
  17. Accessing Shared Resources from the MEGA65 System Partition
  18. Embedding Shared Resources in the MEGA65 System Partition
  19. MEGAphone Bluetooth module
  20. MEGAphone Fabrication of the first module PCBs
  21. MEGAphone Battery Management and Energy Harvesting Module
  22. MEGAphone SIM Card / SD Card Module
  23. MEGAphone Cellular Modem Module
  24. MEGAphone low-current DC:DC Converter Module
  25. Procedural Generation of Panelised Modules and Reducing Costs of Castellated Boards
  26. Procedural Generation of MegaCastle Castellated Symbols
  27. Procedural Generation of Castellated Footprints
  28. MEGAphone 3.5mm Audio Jack Module
  29. MEGAphone Audio CODEC / Speaker Driver Module
  30. MEGAphone Home SMD Assembly Options
  31. MEGAphone MEMS Microphone Module
  32. MEGAphone 2A DC:DC Converter Module Design
  33. Modular MEGAphone Requirement Specification

2024 17

  1. Testing the castellated module format
  2. Modular MEGAphone: Prototyping castellated modules
  3. Modular MEGAphone Kick-Off -- Designing a simple and effective module interface
  4. Tracking down 1581 lock-up on R3 boards
  5. Hardware Accelerated IEC Controller -- Part 5
  6. Flashing the MEGA65 keyboard without a MEGA65
  7. Controlling a EC25-AU cellular modem using a MEGA65
  8. Expansion Board revE Bring-Up and Shake-Down - Part 1
  9. M1565 External Drive Controller Board Design
  10. Expansion board revD and new connector PCBs
  11. More cartridge port fixes for the MEGA65
  12. MEGA65 R5 Cartridge Port VHDL Fixes
  13. Switching from CC65 to LLVM-MOS for the MEGA65 browser
  14. Working on the Expansion Board: User-Port bring-up and other bits and pieces
  15. Working on the Expansion Board: Board Bus and Tape Port bring-up
  16. Hardware Accelerated IEC Controller -- Part 4
  17. Hardware-Accelerated IEC Serial Bus -- Part 3 - JiffyDOS

2023 14

  1. Hardware-Accelerated IEC Serial Interface - Part 2
  2. Tracking down and fixing the thumbnail images in the freezer
  3. R5 Board Bring-Up
  4. Fixing Yet Another HyperRAM Bug
  5. Reading Amiga disks in the MEGA65
  6. Hardware-Accelerated IEC Serial Interface - Part 1
  7. Debugging SDRAM and HyperRAM cache and other related things
  8. Debricking MEGA65 R3/R3A Boards with De-programmed MAX10 FPGAs
  9. Last minute changes to the R4 board
  10. Enabling the Super-Cap on the MEGA65 R4 PCB
  11. MEGA65R4 Bring-Up
  12. Hi-res V200 character mode
  13. Adding colour to the MEGA65's Composite Output
  14. Comparing the Graphics Capabilities of the MEGA65 and Amiga

2022 17

  1. Working on Composite Video Output for the MEGA65 Expansion Board
  2. DIY Keyboard revB works!
  3. Progress on the DIY Keyboard
  4. Working around 74LVC165 supply problems for the MEGA65 Expansion Board
  5. Let's start doing something about those missing expansion ports
  6. MEGA65 MK-II Keyboard PCB Design
  7. DIY USB JTAG and UART connection for the MEGA65
  8. Adding proportional text support to the MEGA65's "web" browser
  9. Working on the "web" browser for the MEGA65
  10. MEGAphone R4 PCB Bring Up -- Part 3
  11. MEGAphone R4 PCB Bring-up -- Part 2
  12. MEGAphone R4 PCB Bring-up Part 1
  13. TEI0004 JTAG Adaptor adaptors can now be ordered
  14. Using a TE0004 JTAG adapter in place of a TE0790 JTAG adapter
  15. The "Chipageddon" parts shortage is weird
  16. Solving the last of the digital video output glitching, at least I think so
  17. MEGA65 PCB Population

2021 18

  1. More work on HD floppies, RLL encoding, disk density auto-detection and other fun
  2. Creating a simple internal drive fast-loader for the MEGA65
  3. Speeding up the MEGA65 flash menu
  4. Adding transparent support for HD floppies
  5. Fixing some CPU timing and floppy formatting bugs
  6. Write and format support for the internal floppy drive
  7. Debugging TCP/IP Problems
  8. Work on a Simple HTTP-based file browser
  9. EnteringThe DOS Maze
  10. Work on floppy formatting, CRC calculation and sector writing
  11. Working on floppy writing
  12. MEGAphone PCB Re-spin
  13. Debugging the 32-bit virtual-register instructions
  14. Working on a simple ethernet-enabled terminal programme for the MEGA65
  15. Guest Post from Bitshifter: Fixing the Oldest and Nastiest Bug in Commodore BASIC
  16. Fixing initial problems discovered by DevKit owners
  17. Guest post from Bit Shifter: Improving the C65 ROMs
  18. ZX-Spectrum on the MEGA65

2020 38

  1. Announcing the MEGA65 Developer Support Programme
  2. DevKits are appearing around the world!
  3. The DevKits have started shipping!
  4. MEGAphone PCB Changes
  5. MEGAphone r2 Hardware Bringup
  6. Pulling out the big guns for improving compatibility with HDMI monitors
  7. Sprite Editor Progress Report
  8. Chasing down HyperRAM controller bugs
  9. Fixing the remaining ethernet RX bugs
  10. OpenROMs Update
  11. Debugging IEC port on MEGA65 R2/R3 boards
  12. MEGA65 R3 PCB Testing
  13. MEGA65 Revision 3 PCB Samples For Testing
  14. MEGA65 Emulator and Tools Live ISO
  15. ACME Support for the MEGA65's 45GS02 CPU, Porting HYPPO to ACME
  16. Updated m65dbg tool
  17. QMTECH Wukong board support and Audio over Digital Video testing
  18. Porting a Wolfenstein-type engine to the MEGA65
  19. First MEGA65 Commercial Software Announced! Hibernated 2
  20. Built-in Sprite Editor Progress
  21. Ultrasonic communications for the MEGAphone: Testing speaker and microphone performance
  22. Pre-Ordering for the MEGA65 Developer's Kits (DevKits) is nigh!
  23. Fit testing the injection moulded case sample
  24. Fixing some floppy bugs
  25. Injection Moulding Tooling Update
  26. Improving the MEGA65 Audio Mixer
  27. Injection Moulding Tooling Progress
  28. More work on the RAM Expansion and Timing Closure
  29. Trying another approach to HDMI-compatible Audio
  30. Getting the other 8MB of RAM working
  31. Misleading ERROR: [Synth 8-2396] from Vivado SOLVED
  32. Starting work on a libc for the MEGA65, and further work on QSPI flash updating
  33. Making the Real-Time Clock Tick
  34. Getting the external microSD card slot working
  35. Almost 65K€ in $65 days!
  36. Adventures in talking to the QSPI flash
  37. Programming the Bitstream Boot Flash and all things JTAG
  38. Running multiple bitstreams

2019 53

  1. MEGA65 DevKit prototype r2
  2. MEGA65 DevKit prototype assembly
  3. The long winding path to getting HDMI Audio working
  4. Writing the 2019 Christmas Demo
  5. Fixing raster counting and freeze synchronisation for PAL50 video mode
  6. (Just about) cycle-perfect PAL 50Hz HDMI video on the MEGA65
  7. More work on HDMI video output
  8. Improving raster timing accuracy / Preparing for HDMI output
  9. MEGA65 Interview in the latest brotkastenfreun.de podcast
  10. Guest post from Wayne on the MEGA65 User Guide Layout
  11. Open C64 ROMs Guest post update
  12. BASIC 10 Reference
  13. (Even) More Assembly
  14. Changing the drive number of the internal drives
  15. More Assembling of MEGA65 Pre-Series Machines
  16. MEGAphone rev2 PCB assembly work
  17. Assembing the next few Pre-Series Machines
  18. Last day of current MEGA65 development sprint
  19. Internal floppy drive now working on the R2 PCB, and various other bits and pieces
  20. IEC port testing / GEOS for the MEGA65 R2 PCB
  21. Getting the MEGA65 R2 Cartridge Port Working
  22. The keyboard is now fully working!
  23. Getting the keyboard working with the MEGA65 R2 main board
  24. Bringing up the SD card interface on the MEGA65 R2 PCB
  25. Programming the MEGA65 keyboard CPLD
  26. Pictures updated on the website
  27. Selective disconnection of FTDI_SIO serial driver from USB adapters
  28. R2 PCB serial monitor interface
  29. Starting to bring the MEGA65 R2 PCBs up
  30. Second Revision MEGA65 Mainboards
  31. Making the internal speaker work on the MEGA65 phone/handheld
  32. Manufacture of pre-series keyboards
  33. MEGAphone prototype is taking shape
  34. Laser-cutting a spacer for the MEGAphone prototype
  35. MEGAphone screen testing
  36. Working to reduce the attack surface for copyright infringement claims against our open-source C64 ROMs
  37. Free and Open-Source Replacement ROMs for the C64
  38. Name Plates for the MEGA65 pre-production units have arrived!
  39. MEGAphone First Prototype PCB remediation and first light
  40. MEGAphone First Prototype PCB assembly complete(ish)
  41. MEGAphone First Prototype PCB assembly underway
  42. Speeding up formatting and freezing with multi-sector SD card writes
  43. Introduction to using the MEGA65 as at 3 March 2019
  44. Auto-Detecting Required Revision of DMAgic Chip, improving default audio mixer settings
  45. Multiple Freeze Slots
  46. Audio Mixer in Freeze Menu and Fixing SID Problems
  47. Towards Dual SD-Card Support
  48. Floppys, floppys everywhere!
  49. Fixing Sprite Rendering Problem
  50. The MEGA65 at Linux Conf AU
  51. Livening CPU speed, video mode and monitor in freeze menu
  52. More work on the MEGA65 built-in freezer
  53. Working on the MEGA65 Freeze Menu

2018 52

  1. Super simple Protovision-Compatible Joystick Expander for MEGA65
  2. M.E.G.A 6502 benchmark for checking cycles per instruction
  3. Real-time CPU tracing
  4. The last few days i have been trying to
  5. MEGAphone - connecting the cellular modem and audio interface
  6. Tool for easily transferring files to/from SD card via serial
  7. Just because a splash screen is obligatory...
  8. More work getting ready for presenting the MEGA65 at Linux Conf
  9. Vertical border knockout for Wizball
  10. Working on the user's guide
  11. Video closure more or less done. Alpha-blending fixed along the way. Proportional text rendering looking quite nice.
  12. More work on video mode closure
  13. Improving timing closure with stable 50/60Hz video
  14. Taking the big picture view
  15. Revisiting proportional text rendering
  16. Stable 50Hz and 60Hz video
  17. Keyboard prototypes have been manufactured, and they are AMAZING
  18. Freezing and the MEGA65 System Partition -- part 1
  19. Resurrecting the MEGA65 VNC server interface
  20. Migrating from Xilinx ISE to Xilinx Vivado FPGA software
  21. GOSUB variable in C64 BASIC
  22. Optimising infinite loops with VHDL
  23. Creating files on a FAT32 filesystem, and making it simpler to implement
  24. Extending The Commodore 64 BASIC with 1st-class tokens
  25. First steps towards MEGA BASIC for the MEGA65
  26. Creating some documentation on the MEGA65's enhanced text mode
  27. Raster splits in BASIC
  28. Displaying 256 colour images and 16 colour sprites
  29. MEGA65 configuration utility / Konfigurations Programme
  30. Testing 16-colour sprite mode
  31. Improving the ethernet adapter
  32. Upgrading the SD card controller: SDHC cards now work!
  33. Freezing and Unfreezing - part 1
  34. Improving the DMAgic controller interface
  35. Repairing an Amiga Mouse, and then using it on the MEGA65
  36. Rebuilding SD card access
  37. Improving my bench MEGA65 prototype hardware
  38. Bringing the internal 3.5" floppy drive to life - part 2
  39. Bringing the internal 3.5" floppy drive to life - part 1
  40. Testing Ethernet on the r1 PCB
  41. Repairing my 1581
  42. Fixing a variety of sprite rendering bugs
  43. 1351 Mouse and paddles now work on the MEGA65 rev1 PCB
  44. Fixing various niggly problems
  45. Curious problems and that Super Games banked cartridge
  46. Fixing 1351 support, and planning auto-detection and support of Amiga mouses
  47. Working on paddles and mouse support
  48. Hooking up the 3.5" internal floppy drive
  49. [M]Ultimax and other Cartridges on the MEGA65
  50. MEGA65 Boots GEOS ... From a serially attached 1571
  51. The detective work in getting International Soccer running on the MEGA65, direct from cartridge
  52. Fixing a few rendering glitches and re-testing enhanced sprite modes.

2017 29

  1. Connecting a C64 disk drive to the MEGA65 - part 2
  2. Connecting a C64 disk drive to the MEGA65 - first success
  3. Building Joysticks
  4. A day of squashing bugs
  5. Preparing to implement the VIC-III DAT
  6. Fixing IRQ following BRK / BoulderMark score = 102x stock C64
  7. Automatic VIC-II Compatibility Regression Testing - Part 1
  8. Instruction-Level Timing Accuracy is here
  9. Automatic 4502 / 6502 Instruction Set Switching
  10. 1351 Mouse Progress: Accuracy better than the original
  11. That recent C65 sale on ebay
  12. 1351 Mouse Progress: Detecting when the SID chip drains the POT lines
  13. First steps towards 1351 mouse support for MEGA65 and MEGAstick
  14. Launching FDISK+FORMAT direct from boot sequence
  15. Hardware animating the on-screen keyboad
  16. Solid-state Joystick
  17. On-screen keyboard display
  18. Fast booting the MEGA65 with custom bitstream, kickstart and ROMs
  19. Getting 1080p 50Hz working ... using a video mode editor written in BASIC v2
  20. Revamping Hypervisor boot display, and SPACE to enter utility menu
  21. Fast-loading via serial monitor for development (part 2)
  22. Fast-loading via serial monitor for development (part 1)
  23. Building lab-prototype MEGA65, and remembering the thrill of my first C65
  24. Powering up the MEGA65 prototype PCB at home
  25. My MEGA65 Prototype PCB has emerged from the postal system
  26. FDISK and FORMAT utility for the MEGA65
  27. Pulling pieces together for the new PCB: Matrix mode, preliminary cartridge support and updated video mode
  28. Prototype MEGA65 PCBs at Revision 2017
  29. Emulating an 8080 on the MEGA65

2016 16

  1. Working on the MEGA65 IDE
  2. MEGA65 Emulator can run kickstart and disk menu
  3. Double-tap RESTORE to enter Hypervisor "freezer"
  4. Tutorial Video for m65dbg
  5. We can include GEOS with the MEGA65
  6. Booting GEOS on the MEGA65
  7. We finally have the new disk menu mostly working
  8. Revenge of the Decimal Flag
  9. On cycle count predictability and related things
  10. Overview of the new CPU design (as of today)
  11. Planning for stability, and the case for re-working the CPU
  12. We've entered the MEGA65 into this year's hackaday contest
  13. First community developed title with MEGA65 support?
  14. Prototyping the keyboard
  15. We're still alive / Wir leben noch
  16. Making Hypervisor debugging easier

2015 52

  1. Is this the first academic slide presentation using an 8-bit computer since the 80's?
  2. 3D printing friction-hinges for the laptop prototype
  3. Photos of laptop prototype work
  4. MEGA65 @ Amiga30.de - Part 5 - RJ Mical meets the MEGA65 prototype
  5. Working towards bitplanes and GeoRAM + REU support
  6. MEGA65 @ Amiga30.de - Part 4
  7. MEGA65 @ Amiga30.de - Part 3
  8. MEGA65 @ Amiga30.de - Part 2
  9. MEGA65 @ Amiga30.de - Part 1
  10. MEGA65 prototype to be displayed at Amiga30 in Germany in a few days
  11. Fast booting from Flash
  12. Making speed control easier
  13. MEGA65 being controlled by a real C65 keyboard
  14. It moves!
  15. Powering the laptop
  16. Some laptopification preparations
  17. Aren't new computers better than 8-bit computers?
  18. Hi-res bitplane mode sprites now working!
  19. Bitplane-mode/"attached" sprites working in multi-colour mode
  20. Screen shots of debugging enhanced sprites
  21. More work on sprites
  22. Some Sprite Bug Fixes
  23. Planning which ports we can support
  24. Teaching the young to program
  25. Nexys4 DDR Boards are out of stock everywhere it seems
  26. Wir sind in den Nachrichten
  27. Introducing the MEGA65 Retro Computer
  28. Generalised disk access routines now work
  29. More work on disk routines
  30. Making the SD access routines available from outside the hypervisor
  31. Making kickstart a little prettier
  32. Character ROM Copyright (Part 2)
  33. Is the C64 font protected by copyright?
  34. C65GS Plays Games at Revision 2015
  35. About C65GS Memory
  36. C65GS at Revision 2015, and running on DDR
  37. Slowing of Moore's Law, FPGAs and Open Hardware
  38. Well, I can load the ROM into the DDR RAM now ...
  39. GHDL Simulation is working again, making it much easier to track down DDR controller bugs
  40. Hypervisor Upgrading and DDR Memory Lockup-fix
  41. Getting closer on the DDR memory front
  42. Improving the hypervisor environment
  43. I still don't like passing signals between clock domains
  44. The Commodore 64C Case moulds still exist!
  45. Reworking the DDR memory controller
  46. I haven't blown up my DDR RAM, so that's good
  47. Still almost working on the Nexys4DDR board
  48. Almost all working on the Nexys4DDR board
  49. First light on the Nexys4DDR board -- but some significant problems remain
  50. I had a few minutes to work on moving to the Nexys4 DDR board
  51. A screenshot for those who are getting bored looking at FPGA boards and want to see something fun
  52. Nexys4 DDR board arrives

2014 85

  1. RAM Upgrade
  2. LCD Screen Test
  3. Some parts for laptop prototyping have arrived
  4. Working on the anti-aliaser
  5. Proportional font glitches fixed
  6. First steps towards a C65GS laptop
  7. Migrating to Vivado (Part 3)
  8. Migrating to Vivado (Part 2)
  9. Migrating from ISE to Vivado (Part 1)
  10. Even more progress on proportional fonts
  11. More work on proportional fonts
  12. Easily Accessing All of Memory
  13. Starting to write tests for 16-bit text mode, including proportional fonts
  14. More work on proportional fonts
  15. Loading data via ethernet
  16. More work towards hardware proportional fonts
  17. Hardware support for proportional fonts and other text mode effects
  18. My real C65 keyboard has arrived, very well wrapped
  19. Hardware thumbnail generation is now usable
  20. Hardware thumbnail generator for task-switcher
  21. A 3rd party operating system for the C65GS?
  22. Virtualisation and Task Switching
  23. Sprites behind the border, and another bug discovered
  24. Confirmed that I have fixed the sneaky CPU bug
  25. Found a sneaky CPU bug
  26. More work on sprites
  27. Initial work on sprites
  28. RR-NET emulation dramas
  29. Remote keyboard access now works
  30. Remotely view and interact (awkwardly) with the C65GS!
  31. More work on remote display
  32. Working towards remote head
  33. Boulder Mark at 48MHz, with working sound
  34. SID audio at last, plus CPU and VIC-IV redesign catching
  35. De jevu: C65 startup banner and dead BASIC, again.
  36. 80 column now has side borders and other misc progress
  37. Ethernet receiving now has hardware CRC check, and IRQs are close
  38. Ethernet transmission
  39. Starting work on the ethernet adapter
  40. Why hardware is hard
  41. First speed test of 48MHz CPU
  42. Debugging the new CPU
  43. Improved hardware scaler
  44. More work on new CPU, and some very skinny raster stripes
  45. New CPU is working (sort of)
  46. Improving simulation of the C65GS to help with debugging
  47. Stunt Car Racer at 29x Speed
  48. A frustrating fortnight of work reimplementing the CPU
  49. Did I mention that FPGA development is frustrating?
  50. Another speed bump. Now close to 30x C64 speed
  51. A speed improvement
  52. multi-colour bitmap and character modes now mostly working
  53. Multi-colour text and graphics closer to working
  54. C65GS begins to run real software, sort of.
  55. First words and a new skin
  56. DMAgic colour RAM bug fixed
  57. Video of latest progress
  58. BASIC now mostly working in C65 mode
  59. Beginning to rework the VIC-IV to support DMA delay and other things
  60. Simple disk chooser to pick D81 files from the SD card
  61. The internal drive now works (for reading)
  62. Floppy controller emulation now partly works
  63. Getting closer with the C65 DOS
  64. Progress towards making the 1581 DOS work
  65. C65-mode ML Monitor is working
  66. Progress towards CPU speed-ups
  67. Running synthmark64 before optimisation of CPU
  68. Hello World from the C65 ROM
  69. Two steps forward, one step back, and perhaps one sideways as well
  70. C65 start up message without tweaking
  71. Fill command of DMAgic DMA controller implemented
  72. Progress towards booting C65 ROM
  73. Bootstrap ROM now works
  74. Progress on kickstart after a week of pain
  75. Creating the C65GS KickStart ROM
  76. Testing the 4510 CPU
  77. An assembler for 4502/4510 CPUs
  78. Disassembling the C65 C64-mode Kernel
  79. Raster IRQs now work
  80. 256-colour modes now mostly working
  81. Motivations and goals for the project
  82. Debugging character display generation
  83. CPU now passes complete suite of 6502 official opcode tests
  84. BASIC now works
  85. Some screen shots