MEGA65 – Open 8-bit Computer



I just bumped into a link on Facebook for a new 8-bit open sourced computer called the Mega65 – looking at the images of the proposed computer if looks very familiar if you are a Commodore fan. There is a lot of information on the site for the computer, especially the specification of the hardware which is highlighted below.


The proposed MEGA65 computer


CPU 48MHz GS4510 single-core, in-order, no-branch-prediction, no-cache, single-scalar, no-fpu, no-smd, no-HCF, non-pipelined, enhanced 4502 8-bit processor, with 32-bit ZP indirect and 32-bit far-JSR/JMP/RTS operations, 28-bit address space, fast hypervisor traps, virtual memory, IO virtualisation (coming soon).
Speed Synthmark64 score: 44.5x (C64 = 1x). Bouldermark score: 29,970 (C64 = 313).
DMA C65 DMAgic compatible DMA controller. Fills at 48MB/sec, copies at 24MB/sec, swaps at 12MB/sec.
Video Controller VIC-IV advanced rasterised video controller, like the VIC-II and VIC-III no framebuffer. Native resolution 1920×1200 (192MHz pixel clock). Supports all documented VIC-II modes (hi-res, multi-colour mode, extended-background-colour mode, sprites) and VIC-III modes (bitplanes are in the process of adding). Independent horizontal and vertical hardware scaling allows text and graphics resolutions as high as 1920×1200 and as low as 60×38. Separate 256-colour palettes for sprites, bitplanes and character graphics, allowing upto 1,024 colours on screen without changing the palette in real-time. VGA output 12-bit (4,096 colours). The planned DVI/HDMI output will support 23-bit colour (8.3 million colours). Text mode extensions including proportional width characters, super-extended background colour mode, as well as the standard VIC-III extended attributes.
Sound Dual soft-SIDs + dual 8-bit DACs.
RAM 128KB RAM visible to VIC-IV, 32KB colour RAM visible to VIC-IV, 128KB ROM/RAM. 128MB of (extended) DDR2 RAM being worked on to be made accessible.
Media D81 disk images from SD card (native VFAT32 file system support coming soon). Real 3.5″ floppy drive support pLanned. Standard loading speed without fast loader ~20KB second. Loading speed direct from SD card 300 – 3000KB/second (1200 – 12000 blocks per second), depending on SD card.
Outputs Joystick ports 1 and 2 (9-Pin Atari Standard), VGA, 10/100mbit Ethernet,Mono Audio (Stereo soon), USB, Micro USB. Planned: HDMI, analog video, extension port, maybe external floppy.
Inputs USB (supports PC keyboards and adaptor cards), Micro USB, Ethernet, Micro SD slot, and coming soon: 3D accelerometer, on-board microphone and thermometer.
Operating System MEGA-OS all-in-one hypervisor and compat operating system, including integrated freezer and task switcher, VFAT32 file system driver and inter-process communications.
Form factor C65-like all-in-one. A laptop form is planned for a future release. Full-height 19″ rack option extra.
Supported FGPAs Nexys4DDR (and soon) Nexys4PSRAM. These boards include a Xilinx Artix7 100T FPGA, which is a high-performance FPGA, much faster and larger than the Spartan FPGAs used in other retro computing projects. Unfortunately the old Spartan FPGA boards cannot run the MEGA65 core.
Development options Right now: Use Ophis with the -4 option to target the 4502 CPU. The etherload utility can be used to push compiled programs to the MEGA65 practically instantly to make for a convenient cross-platform development environment. For the future: MEGA-OS will support interprocess communications, making it possible to write assemblers and compilers that assemble directly into a separate process, and then launches that process when it is ready. Thus it becomes possible to use the MEGA65 as an 8-bit development platform for 8-bit software (or to run a cross-compiler for Linux or Windows if you wish to be really strange).
Milestones Reached: the computer is fully operational as a stand alone machine. We are now adding bitplanes, extended Hypervisor and more DOS.

The site says the MEGA65 computer is expected to be ready for sale in the third quarter of 2016. If you cannot wait that long and are curious, you can start playing and programming the MEGA65 software now on a NEXYS4 DDR board that is currently available and there are even tutorials on how to get it up and running. This sounds rather complicated for my ageing brain, so I think I will monitor this project closely and see what pops out the other side – hopefully something I can plug in and play.

There is no talk on the site at the moment of how this is going to be funded – maybe a crowd-funding  campaign will be announced in the near future.

Here is a video of the MEGA65 in action:

2 comments for “MEGA65 – Open 8-bit Computer

  1. ufuk cingay
    8th May 2016 at 8:12 pm

    cool or wooot woot or what 🙂

  2. Kurt K
    9th May 2016 at 9:51 am

    What I like is the use of the C65 case and OS. Floppy drive? Cool. Laptop version, hmmm, not sure about that. Perfect for all of us that never will find or afford a C65.

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