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Mega65 is a 100% open source implementation of an enhanced version of the never released Commodore 65 computer. Both the hardware itself are fully open and documented as well as the underlying firmware required for operation. The system has an 8-bit CPU with a handfull of 32-bit instructions implemented in FPGA. The system itself has its own native Mega65 mode with a greatly enhanced version of BASIC. It also has a Commodore 64 mode with a level of compatibility similar to that of the Commodore 128 in C64 mode.
 Hardware Specifications
- 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 1920x1200 (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 1920x1200 and as low as 60x38. 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.
- ↑ http://c65gs.blogspot.de/2016/08/we-can-include-geos-with-mega65.html