Commander X16 vs. Mega 65

martinot · Post by **martinot** » Wed Jan 26, 2022 10:12 am

On 1/26/2022 at 1:57 AM, Scott Robison said:

I'm sure it's awesome for people who have fond memories of Sinclair & Spectrum in particular. I'm just not one of those people.

Well, I personally think we pure retro enthusiats can see beyond the religious wars and appreciate all nice 8-bit machines for what they are. ?

I never had any Spectrum as young, and neither any Commodore machine, but the Spectrum Next is an really awesome new 8-bit retro machine! ?

Scott Robison · Post by **Scott Robison** » Wed Jan 26, 2022 4:12 pm

On 1/26/2022 at 3:12 AM, martinot said:

Well, I personally think we pure retro enthusiats can see beyond the religious wars and appreciate all nice 8-bit machines for what they are. ?

I never had any Spectrum as young, and neither any Commodore machine, but the Spectrum Next is an really awesome new 8-bit retro machine! ?

As my original response to the question said, I've thought about it, but I'm not "standing in line" for one. By which I mean I don't feel like ordering one and waiting an indeterminate period of time for it to arrive. The team is still working out supply chain issues.

Waiting for MEGA65 is hard enough.

Plus, I suspect at some point there will be Sinclair cores available for MEGA65. The reverse won't be true, most likely.

In any case I've not ruled out ever having a Next, but not ordering one today.

paulscottrobson · Post by **paulscottrobson** » Wed Jan 26, 2022 10:15 pm

On 1/26/2022 at 4:12 PM, Scott Robison said:

As my original response to the question said, I've thought about it, but I'm not "standing in line" for one. By which I mean I don't feel like ordering one and waiting an indeterminate period of time for it to arrive. The team is still working out supply chain issues.

Waiting for MEGA65 is hard enough.

Plus, I suspect at some point there will be Sinclair cores available for MEGA65. The reverse won't be true, most likely.

In any case I've not ruled out ever having a Next, but not ordering one today.

I still think they're working out basic design issues. I don't think it's reached a "we can start building tomorrow if we get the bits".

Next is Open, so there are already alternate Next PCBs without a case e.g. https://www.vintageisthenewold.com/retroshop-announces-the-first-zx-spectrum-next-clone-board

Going to be like the M65 ; you can have a cheap one or an expensive one with all the gimmicks/special case etc.

Scott Robison · Post by **Scott Robison** » Thu Jan 27, 2022 4:19 am

On 1/26/2022 at 3:15 PM, paulscottrobson said:

I still think they're working out basic design issues. I don't think it's reached a "we can start building tomorrow if we get the bits".

Next is Open, so there are already alternate Next PCBs without a case e.g. https://www.vintageisthenewold.com/retroshop-announces-the-first-zx-spectrum-next-clone-board

Going to be like the M65 ; you can have a cheap one or an expensive one with all the gimmicks/special case etc.

At least one of the issues they're working out is using a new FPGA chip because their old chip is not going to be supported going forward.

If I were to get a Next it'd be the nice looking one. It just doesn't scratch an itch I have at present.

lydon · Post by **lydon** » Wed Feb 09, 2022 2:44 pm

On 1/27/2022 at 5:19 AM, Scott Robison said:

At least one of the issues they're working out is using a new FPGA chip because their old chip is not going to be supported going forward.

And the new chip for the SpeccyNext is actually a Artix-7 XC7A15T, which is a little sister of the MEGA65s Artix-7 XC7A200T (has more than 10 times the logic resources).

A few days ago I got the ZX Uno core running on my MEGA65... really nice ? (the GBA core I don't really see on the MEGA65, it's more something for my MiSTer).

The MEGA65 hardware platform is aimed to be used with other cores. True, it is expensive, but the more cores we get running on it, the better the money to pain ratio gets.

Scott Robison · Post by **Scott Robison** » Wed Feb 09, 2022 4:07 pm

On 2/9/2022 at 7:44 AM, lydon said:

The MEGA65 hardware platform is aimed to be used with other cores. True, it is expensive, but the more cores we get running on it, the better the money to pain ratio gets.

That's a big reason why I ordered my MEGA65.

Michael Kaiser · Post by **Michael Kaiser** » Sat Dec 31, 2022 6:43 am

On 7/23/2021 at 11:08 AM, Kalvan said:

Here's my attempt to make side-by-side comparisons of the Commander X16, C256 Foenix, and Mega65:

Commander X16

C256 Foenix

Mega65

CPU

WDC [email protected]

WDC 65816 @14.28 Mhz, Choice of extra CPU Options (256 GEN-X and Above, not relevant to this comparison)

Custom FPGA Core based on the MOS Technology 4510@40 Mhz

System RAM

560K Standard (48K Low RAM, 512K High RAM), Maximum of 2 MB available by populating all RAM sockets. Memory Map presumably can address up to 2,112K Total

Up to 64MB Standard (System can address no more than 8 MB on 65816 power alone), 2 to 4 MB on Foenix U/U+.

Current standard and maximum physical RAM To Be Decided. CPU possesses 28-bit address bus, capable of addressing up to 256MB, Full memory map recently preliminarily published

GPU

VERA, Separately Addressed Video RAM, 128K (Memory resources shared with PSG and PCM audio subsystems) (*)

VICKY II/III, Separately Addressed Video RAM (4MB VICKY II, 8 MB VICKY III)

VIC IV, Video RAM Space within larger System RAM can be remapped up to 16 MB, but is mapped to 384K by default in Mega65 Mode Pixel Clock at double CPU clock speed.

Resolution

320x240 (256 Colors Tile, 1024 Colors Bitmap), 320x480, 640x240 (64 Colors Tile, 256 Colors, Bitmap), 640x480 (16 Colors)

320x240, 256 Colors (65536, VICKY III)

400x300, 256 Colors (65536 VICKY III)

512x384, 256 Colors (65536, VICKY III)

640x480, 256 Colors

800x600, 256 Colors

1024x768, 236 Colors (VICKY III Only)

All resolutions from VIC-20 and Commodore 64, Plus

360x288 (1024 Colors 256 Color Sprite CLUTs)

400x300

640x400

720x576

800x600 (@)

Sprites

Maximum of 128 4-bit pixel (16 color) or 64 8-bit pixel (256 color) sprites, or mix and match in a 2-1 ratio. Sprite size programmable up to 64x64 pixels. Maximum of 32 sprites per scanline (16 8-bit pixel)

Maximum of 64 32x32 pixel sprites. No Scanline Limits, bit width per pixel unknown

Maximum of 2048 4 bit-per pixel sprites at stock memory configuration in Mega65 Mode. Sprite size programmable up to 64x32, 32x64 or 8x256 pixels, but defaults to the stock Commodore 64 12x23. Maximum of 65,536 sprites when all memory slots are full

Fields

Maximum of Two Tile Fields, or one tile and one bitmap. Bitmap field lacks scrolling registers and must be scrolled through CPU power alone, but is split into quadrants each with a separate CLUT

Maximum of 4 Tile Fields and 2 Bitmap Fields

Choice of one Tile or Bitmap Field through conventional means, but judicious use of the Raster Rewrite Buffer can permit an arbitrary number of apparent scrolling fields.

Other Features

VideoDMA with Blitter Functions, Enhanced functionality and bandwidth in VICKY III

DMAgic Video DMA+ Raster Rewrite Buffer effectively produce two different extra blitter methods at the same time

Master Palette

4096, four bits each of RGB

16,777,216, eight bits each of RGB

8,338,608, color generation scheme unknown

Sound Chips

Yamaha YM2151+YM3012 DAC, 8 Channels FM Synthesis, 4 operators, 4 possible waveforms,

16 Channels Geometry Synthesis, 4 possible waveforms, 8 sets of two adjacent channels can be combined for more complex sounds.

1 channel 16-bit PCM synthesis, 48 KH maximum sample rate, 4K audio buffer

Yamaha YM2151+YM3012 DAC

Yamaha YM2612, 6 Channels 4 operator FM Synthesis

Yamaha YMF262 (Several different modes of FM Synthesis + available 5-piece percussion set),

Texas Instruments SN76489 (3 Channels general Geometry synthesis, 1 channel sawtooth and white noise)

X2 Gideon SID Core (6 channels total geometry synthesis, multiple filter options)+ socket space on the motherboard for two physical SID replacement chips,

Red Box (CD Quality) CODEC

X4 SID Softcores (12 Sound Channels total), two based on the original Commodore 64 version, and two based on the Commodore 128/Later 64 version, four available sockets on the motherboard for physical SID replacement chips.

Yamaha YMF278 (FM Sound Channels from YMF262+24 PCM Channels with 16-bit sampling@44KHz, based on the Yamaha YMW258-F/Sega Multi-PCM, Successor to the SegaPCM chip used in several Sega arcade games, used in the Yamaha SoundEdge PC Sound Card and the MSX Moonsound expansion cartridge)

DMagic DMA Controller can also be used to play four channel raw digital samples.

I/O

VGA Output, A/V Multi-out, PS/2 Keyboard and Mouse, X2 7-pin Super NES controller jacks with headers for 2 more on the motherboard for an expansion backplane, Commodore-styled User Port (electrical profile based “mainly” on the Commodore 64/128 version), SD Card Slot, X4 expansion card slots, based on the Apple II Standard

Varies by form factor. Mid-Tower and Full Tower Backplanes have: VGA Output, A/V Multi-out, Single-Link DVI Output, PS/2 Keyboard and Mouse, X4 Each Atari CX-9, 7 Pin NES, and 7 Pin Super NES controller jacks, SD Card Slot, X4-6 expansion card slots, physical, electrical, and protocol set profile currently unknown

VGA Output, A/V Multi-out, SCART out, X2 Atari CX-9 joystick Jacks with two extra headers on the motherboard for an expansion backplane. X2 USB 1.2 Ports, Commodore User Port (Electrical Profile based on Commodore 64/128), Commodore 64 Cartridge Slot, Commodore Floppy and Datasette ports, X1 3.5” Floppy Disc (&)

Form Factor

Horizontal Upright, Separate keyboard optional. Smaller form factor models projected in the future

Choice of Bare Motherboard, Small Form Factor(roughly Intel NUC/Mac Mini sized), Keyboard Console, Mid Tower, and Full Tower

Keyboard Console

OS

Kernal + Commodore DOS, GEOS GUI

Unknown OS for 65816. Motorola 680X0 processor upgrades offered with choice of EmuTOS+FreeMINT or Microware OS/9.

x86 processor upgrades offered with DOSBox+ReactOS, ARM upgrades offered with choice of some sort of Linux distribution or OpenRISC (%)

Kernal + Commodore DOS, GEOS GUI

Built-in Language

Microsoft BASIC 2.0+additional reserved words and syntax revisions to take advantage of the hardware

Unknown BASIC interpreter Based on Commodore BASIC 2.0

Commodore BASIC 10.0, Mega65 BASIC 11 for Mega65 Mode.

Also not that I did not list prices, because all price quotes are currently preliminary.

Notes:

*: VERA's 128K of Video RAM is the FPGA's fabric cache. Video Memory cannot be increased.

@: the VIC III 1280x200 and 1280x400 resolution modes of the Commodore 65 are not supported due to a lack of availability of Commodore 65-spec CRT monitors, and the rarity and expense of 2560x1600 5:8 aspect fixed pixel monitors.

&: Two Atari CX-9 Commodore 64 Mouse protocol/USB dongles allegedly packed in

% Full Compatibility with classic MS-DOS software stack and classic Ad-Lib and SoundBlaster support not guaranteed with x86 processor options. Full compatibility with Atari TOS/MINT software stack with 680X0 CPU option not guaranteed. Full Compatibility with classic Acorn Archimedes/RISC PC software stack not guaranteed with ARM CPU option.

I've written code for both the Commander X16 and the Mega65. The Mega65 initially appears to be superior. However I found two things that tip me back to Commander x16. First, the raster rewrite buffer is WAY harder to use than simply having lots of Sprites. Second, it initially seems cool that the Mega65 has a 28 bit address space directly accessible from the processor, but when you come down to it you still need top map executable code into the first 64k, and it takes 8 - 9 clock cycles to do accesses to the RAM above 64k, potentially more because you have to setup double-word pointers. When it's all accounted for you're usually slinging around 2-4x as much data so you offset the 40Mhz speed and come up with an effective comparable speed of 10Mhz compared to the Commander X16. The DMA of the Mega65 seems cool, but it is not fully implemented in the emulator. When it's all done, I'm far more productive on the Commander X16 than on the Mega65.

	Commander X16	C256 Foenix	Mega65
CPU	WDC [email protected]	WDC 65816 @14.28 Mhz, Choice of extra CPU Options (256 GEN-X and Above, not relevant to this comparison)	Custom FPGA Core based on the MOS Technology 4510@40 Mhz
System RAM	560K Standard (48K Low RAM, 512K High RAM), Maximum of 2 MB available by populating all RAM sockets. Memory Map presumably can address up to 2,112K Total	Up to 64MB Standard (System can address no more than 8 MB on 65816 power alone), 2 to 4 MB on Foenix U/U+.	Current standard and maximum physical RAM To Be Decided. CPU possesses 28-bit address bus, capable of addressing up to 256MB, Full memory map recently preliminarily published
GPU	VERA, Separately Addressed Video RAM, 128K (Memory resources shared with PSG and PCM audio subsystems) (*)	VICKY II/III, Separately Addressed Video RAM (4MB VICKY II, 8 MB VICKY III)	VIC IV, Video RAM Space within larger System RAM can be remapped up to 16 MB, but is mapped to 384K by default in Mega65 Mode Pixel Clock at double CPU clock speed.
Resolution	320x240 (256 Colors Tile, 1024 Colors Bitmap), 320x480, 640x240 (64 Colors Tile, 256 Colors, Bitmap), 640x480 (16 Colors)	320x240, 256 Colors (65536, VICKY III) 400x300, 256 Colors (65536 VICKY III) 512x384, 256 Colors (65536, VICKY III) 640x480, 256 Colors 800x600, 256 Colors 1024x768, 236 Colors (VICKY III Only)	All resolutions from VIC-20 and Commodore 64, Plus 360x288 (1024 Colors 256 Color Sprite CLUTs) 400x300 640x400 720x576 800x600 (@)
Sprites	Maximum of 128 4-bit pixel (16 color) or 64 8-bit pixel (256 color) sprites, or mix and match in a 2-1 ratio. Sprite size programmable up to 64x64 pixels. Maximum of 32 sprites per scanline (16 8-bit pixel)	Maximum of 64 32x32 pixel sprites. No Scanline Limits, bit width per pixel unknown	Maximum of 2048 4 bit-per pixel sprites at stock memory configuration in Mega65 Mode. Sprite size programmable up to 64x32, 32x64 or 8x256 pixels, but defaults to the stock Commodore 64 12x23. Maximum of 65,536 sprites when all memory slots are full
Fields	Maximum of Two Tile Fields, or one tile and one bitmap. Bitmap field lacks scrolling registers and must be scrolled through CPU power alone, but is split into quadrants each with a separate CLUT	Maximum of 4 Tile Fields and 2 Bitmap Fields	Choice of one Tile or Bitmap Field through conventional means, but judicious use of the Raster Rewrite Buffer can permit an arbitrary number of apparent scrolling fields.
Other Features		VideoDMA with Blitter Functions, Enhanced functionality and bandwidth in VICKY III	DMAgic Video DMA+ Raster Rewrite Buffer effectively produce two different extra blitter methods at the same time

Master Palette	4096, four bits each of RGB	16,777,216, eight bits each of RGB	8,338,608, color generation scheme unknown
Sound Chips	Yamaha YM2151+YM3012 DAC, 8 Channels FM Synthesis, 4 operators, 4 possible waveforms, 16 Channels Geometry Synthesis, 4 possible waveforms, 8 sets of two adjacent channels can be combined for more complex sounds. 1 channel 16-bit PCM synthesis, 48 KH maximum sample rate, 4K audio buffer	Yamaha YM2151+YM3012 DAC Yamaha YM2612, 6 Channels 4 operator FM Synthesis Yamaha YMF262 (Several different modes of FM Synthesis + available 5-piece percussion set), Texas Instruments SN76489 (3 Channels general Geometry synthesis, 1 channel sawtooth and white noise) X2 Gideon SID Core (6 channels total geometry synthesis, multiple filter options)+ socket space on the motherboard for two physical SID replacement chips, Red Box (CD Quality) CODEC	X4 SID Softcores (12 Sound Channels total), two based on the original Commodore 64 version, and two based on the Commodore 128/Later 64 version, four available sockets on the motherboard for physical SID replacement chips. Yamaha YMF278 (FM Sound Channels from YMF262+24 PCM Channels with 16-bit sampling@44KHz, based on the Yamaha YMW258-F/Sega Multi-PCM, Successor to the SegaPCM chip used in several Sega arcade games, used in the Yamaha SoundEdge PC Sound Card and the MSX Moonsound expansion cartridge) DMagic DMA Controller can also be used to play four channel raw digital samples.
I/O	VGA Output, A/V Multi-out, PS/2 Keyboard and Mouse, X2 7-pin Super NES controller jacks with headers for 2 more on the motherboard for an expansion backplane, Commodore-styled User Port (electrical profile based “mainly” on the Commodore 64/128 version), SD Card Slot, X4 expansion card slots, based on the Apple II Standard	Varies by form factor. Mid-Tower and Full Tower Backplanes have: VGA Output, A/V Multi-out, Single-Link DVI Output, PS/2 Keyboard and Mouse, X4 Each Atari CX-9, 7 Pin NES, and 7 Pin Super NES controller jacks, SD Card Slot, X4-6 expansion card slots, physical, electrical, and protocol set profile currently unknown	VGA Output, A/V Multi-out, SCART out, X2 Atari CX-9 joystick Jacks with two extra headers on the motherboard for an expansion backplane. X2 USB 1.2 Ports, Commodore User Port (Electrical Profile based on Commodore 64/128), Commodore 64 Cartridge Slot, Commodore Floppy and Datasette ports, X1 3.5” Floppy Disc (&)
Form Factor	Horizontal Upright, Separate keyboard optional. Smaller form factor models projected in the future	Choice of Bare Motherboard, Small Form Factor(roughly Intel NUC/Mac Mini sized), Keyboard Console, Mid Tower, and Full Tower	Keyboard Console
OS	Kernal + Commodore DOS, GEOS GUI	Unknown OS for 65816. Motorola 680X0 processor upgrades offered with choice of EmuTOS+FreeMINT or Microware OS/9. x86 processor upgrades offered with DOSBox+ReactOS, ARM upgrades offered with choice of some sort of Linux distribution or OpenRISC (%)	Kernal + Commodore DOS, GEOS GUI
Built-in Language	Microsoft BASIC 2.0+additional reserved words and syntax revisions to take advantage of the hardware	Unknown BASIC interpreter Based on Commodore BASIC 2.0	Commodore BASIC 10.0, Mega65 BASIC 11 for Mega65 Mode.