MEGA65 FORUM

Cartridge support

append delete kerunaru

Hi, there! I was wondering if the Mega65 is going to have a cartridge port in order to support C64 games on this media; I don't actually know if the original C65 had cartridge support and, as Mega65 is a super duper enhanced version of C65, if it didn't have I expect Mega65 wouldn't have neither.

BTW, thanks for your job… This is quite exciting!

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append delete #1. LoveMega65

I hope it have cartridge support! It is a very important feature actually. But also it means if you attempt to insert the cartridge or remove the cartridge while mega65 is ON it would be the end for both your cartridge and Mega65. :D

append delete #2. Deft

There will be support for C64 cartridges which already exists as a prototype. C65 cartridges are non-existant so we chose that option. And we will make sure that pulling/plugging while on will not hurt anyone or anything ;)

append delete #3. MIRKOSOFT

Hm, when I look that original C65 has own expansion port and for use with C64/128 cartridges it needs adapter, now it's different. True is that original C65 exp. port never had any cartridge, it hurts not to replace it by C64/128 exp. port.
When will be able M65 to handle cartridges, is here one Q...
I'm real 128er and owner of SCPU128... How can handle M65 this?
You're asking - what a stupidity?
True is that M65 speed is even more than SCPU, but true is that SCPU can work in 16-bit mode and M65 not...
I'm asking for use 65K CPU family.
BTW. What do you think about handling CP/M cartridge?
Again asking - stupid... But 128 has Z80 and this cartridge too - so I mean no CP/M, I mean X80 CPU family...
Miro

append delete #4. LoveMega65

MIRKOSOFT not a single question you asked is stupid :) I am actually curious what Deft will answer to these questions myself :)

append delete #5. Ratteler

LMFAO at the thought of plugging a SuperCPU into a Mega65.

I too am a 128 fanatic... but it's kind of crazy to support CPM/Z80.

append delete #6. LGB

I have got somewhat stalling project to emulate Z80 (well, 8080 for now) on 65xx (namely C64DTV, since it's faster and give more freedom with the help of memory paging and stack+ZP relocation possibility - what also can be done with 65CE02 as well). It'll be *slow* indeed. However if I understand correctly, somewhat "emulation" in used to emulate the 6510 behaviour of C64 in C65GS too in C64 mode, and the CPU speed may allow (with some extra features like linear RAM addressing in 32 or whatever bits?) to do it quite well even from the view point of decent emulated Z80 performance?

append delete #7. Ratteler

Don't know that you would need to do that. The great thing about an FPGA is that there is no need to "emulate" in the classic sense.

http://opencores.com/project,t80

That just ONE of several Z80's I found that could be executed in FPGA.
If there are enough LE's left when the M65 is done, a Z80 Core could be implemented in addition to the 4510. Sort of a Mega 130 :-D

append delete #8. LGB

Hmm, having Z80 support directly in FPGA would be cool (also for C128 mode, hehe) but it requires FPGA resource then for that ... Anyway if Z80 is implemented, and also have the "hypervisor traps" etc, then it also makes possible to "emulate" other Z80 based computers as well. However, I think it's a bit out of scope of Mega65. Maybe for the C128, it's still somewhat understandable to include, but I hardly believe that it will be included anyway ... It's even interesting to think about on the 65xx line: if "emulation" using "I/O trap" anything makes that possible, other Commodore machines can be "emulated" like C+4 :) But that's at least 65xx ...

append delete #9. MIRKOSOFT

I have new CP/M cartridge for use with Commodore 128 - asking you: why? C128 has Z80!
Yes true for using C128 without SCPU. I own SCPU and it at power on takes control over all and it's impossible to switch to C128's Z80. So, I tried CP/M cartridge and results were amazing.
Z80 works in both modes - 128 and 64, for 64 mode is here CP/M 2.2, CP/M 3.0 in 128 mode is possible to run only with turned off SCPU. Ok, but when is SCPU turned off C128 has available to use 3 CPUs: 8502, Z80 inside C128, Z80 inside CP/M cartridge... so X65 and X80 families.
When is SCPU turned on available are 2 CPUs - and for both modes (128 and 64): 65816 and Z80 inside CP/M cartridge, this means 65K and X80 famiies, so variability of C128 is excellent - most vesatile computer ever made...
You're asking why I'm writting about C128 - this is M65 forum...
Making possible handling SCPU and CP/M cartridge can make Mega 65 more effective computer, 65CE02 in C65 mode, 6502 incl. illegal opcodes in C64 mode, Z80 inside cartridge and 65816 in SCPU - these CPUs are available and it means 65X, X65, 65K and X80 families which open door to new dimension...
So, please don't be angry, I wanted to write possibilities which can or cannot be real...

Miro

append delete #10. Ratteler

It'g going to be nightmare to expose 44 pins as an expansion bus on a FPGA.
If there are enough LE on the FPGA, all that could be implemented IN the FPGA core.
With the ability to load different cores, you could make it anything up to a 680x0 based system with relative ease.

append delete #11. gardners

So, with regard to the cartridge port, as Deft has said, we only plan to support C64 cartridges, and not all of the crazier/more complex ones. There is no need for an REU, for example, when we can read from SD card faster than 1MB/second. Also, using a SuperCPU would just result in the machine running (quite a lot) slower.

As for Z80 support, I appreciate that some people would like this, however, it isn't on our radar at the moment, because we have enough to do to simply create the machine, and the C65 doesn't have a Z80. Also, as mentioned above, it is likely quite possible to get reasonable Z80 emulation using the 48MHz 4510 in the MEGA65. If that isn't the case, then we can worry about finding another solution, but not before we are at the point where you all have MEGA65 computers on your desks.

append delete #12. TRW

A REU support is necessary because there are some games and demos that support a REU.

:: @TRW added on 16 Apr ’16 · 14:58

To see the MEGA as successor to the C64 (and C65) , is (for me) a 99.99% software and hardware compatibility important.

append delete #13. gardners mobile

First, we can transparently emulate an reu from sd card. it will then behave just like the real thing.

As fir 99.99% we would of course love this and work in that general direction. however the c65 is not even 99% c64 compatible. probably not even 80%. Our first goal is c65 compatibility and as much c64 compatibility as possible. by in the end it requires a LOT of work to get each extra 9. You are welcome to help us achieve them, of course.

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