Search found 44 matches

by dentnz
Wed Feb 24, 2021 11:41 pm
Forum: Commodore 16, 64, VIC-20
Topic: A matter of Bits and Cartridges.
Replies: 19
Views: 2566

Re: A matter of Bits and Cartridges.

So good progress with the 1541 ultimate REU implementation. I was able to get it to boot (dma_n signal was defaulting to 0) and eventually got the register reads and writes working. I am now working on the transfers themselves. The 1541 code is actually a lot cleaner and bug free. It is in vhdl, so ...
by dentnz
Wed Feb 24, 2021 3:10 am
Forum: Commodore 16, 64, VIC-20
Topic: A matter of Bits and Cartridges.
Replies: 19
Views: 2566

Re: A matter of Bits and Cartridges.

So I eventually came to the realisation that I was effectively rewriting the existing REU code I was using to be non-tristate. And from there, I realised that the 1541 Ultimate implementation is possibly a better match. I am in the process of getting it integrated into the core now. It should make i...
by dentnz
Mon Feb 22, 2021 4:04 am
Forum: Commodore 16, 64, VIC-20
Topic: A matter of Bits and Cartridges.
Replies: 19
Views: 2566

Re: A matter of Bits and Cartridges.

I don't think the original author of the core implemented hardware pull-up logic in any of the core. You'll probably have to invert those what should be normally high/active low signals coming from the core at your REU interface. The verilog code example was for a real cart to be plugged into a rea...
by dentnz
Thu Feb 18, 2021 11:45 pm
Forum: Commodore 16, 64, VIC-20
Topic: A matter of Bits and Cartridges.
Replies: 19
Views: 2566

Re: A matter of Bits and Cartridges.

So executing the DMA transfer is at least happening. However, I am not seeing the correct data going into the REU (SDRAM). And certainly, attempting to transfer it back again results in nothing happening. It also looks like the state machine gets locked once the transfer is complete. https://cdn.dis...
by dentnz
Tue Feb 16, 2021 10:44 am
Forum: Commodore 16, 64, VIC-20
Topic: A matter of Bits and Cartridges.
Replies: 19
Views: 2566

Re: A matter of Bits and Cartridges.

So good progress. I’ve got the registers working, including writing to the registers. This means that the REU tools detect that a REU is attached, since they usually write a set of numbers into Df02-df07 and check that those numbers can be read back. I’ve yet to test the execute bit, but will look a...
by dentnz
Thu Feb 11, 2021 1:47 am
Forum: SNES
Topic: MSU-1
Replies: 53
Views: 11131

Re: MSU-1

Yes, the looping audio is pretty tricky really, particularly when you have to take into account the fifo buffer. Say the loop point in the msu audio file puts the loop point *byte offset* some way into the file... The algorithm goes something like so: - Work out the SECTOR offset from the loop byte ...
by dentnz
Thu Feb 04, 2021 10:20 pm
Forum: Commodore 16, 64, VIC-20
Topic: A matter of Bits and Cartridges.
Replies: 19
Views: 2566

Re: A matter of Bits and Cartridges.

Some one wrote this REU as well, which may be of some use for example code . . . https://github.com/zeldin/super-reu There is also this document : http://www.zimmers.net/anonftp/pub/cbm/documents/chipdata/CSG8726TechRefDoc-1.0.zip The SuperSnapshot cart is also compatible with the REU and both coul...
by dentnz
Wed Feb 03, 2021 10:09 pm
Forum: Commodore 16, 64, VIC-20
Topic: A matter of Bits and Cartridges.
Replies: 19
Views: 2566

Re: A matter of Bits and Cartridges.

So not much progress at this stage. I believe that the way forward is to add an additional cartridge type to the cartridge module. Then, when it's attached (either via a cart file, or OSD configuration), enable reu with a signal (setting exrom and game signals correctly). The sdram instantiation wou...
by dentnz
Tue Feb 02, 2021 4:19 am
Forum: Commodore 16, 64, VIC-20
Topic: Super CPU Support?
Replies: 14
Views: 1250

Re: Super CPU Support?

Yes I thought I saw that the minimig core had been ported to the Chameleon. Hilarious. As I said, the REU is the first thing I want to try... It will give me an idea of how the DMA flag works. It should be possible to 'disable' the CPU in the c64 and hand over to another CPU running at a faster cloc...
by dentnz
Mon Feb 01, 2021 9:39 pm
Forum: General Discussions
Topic: Retro Arch coming to DE10-Nano this year
Replies: 46
Views: 3132

Re: Retro Arch coming to DE10-Nano this year

I am interested to see if they can get some kind of FPGA <-> HPS hybrid emulation going. I understand that the timings required between the hardware and software would be practically impossible to maintain, meaning accuracy is unlikely... But, it could be a good stop gap while we are waiting for mor...
by dentnz
Mon Feb 01, 2021 9:00 pm
Forum: Commodore 16, 64, VIC-20
Topic: A matter of Bits and Cartridges.
Replies: 19
Views: 2566

Re: A matter of Bits and Cartridges.

Would you be interested in working on REU together? I’ve started to look at it from a cartridge perspective. The easy flash already has the ability for 1mb of paged rom, the REU is much the same, but it has DMA and a set of registers to help bank switching and copying data around between the REU and...
by dentnz
Mon Feb 01, 2021 4:48 am
Forum: SNES
Topic: MSU-1
Replies: 53
Views: 11131

Re: MSU-1

https://www.youtube.com/watch?v=DfY3afu2rzc Audio sounds like it is working well... Better in fact, since opening the OSD does not cause the audio to stutter. I think these are changes that were added to the OSD as part of the MegaCD and PCE CD cores. Video is NOT working however. I have a feeling t...
by dentnz
Mon Feb 01, 2021 4:39 am
Forum: Commodore 16, 64, VIC-20
Topic: Super CPU Support?
Replies: 14
Views: 1250

Re: Super CPU Support?

I've decided to take a look at the ram expansion unit as suggested by Sorgleig. If I have an understanding of how the cartridge slot works, I think I will be in a much better position to work on acceleration of the CPU. I have effectively added a new cartridge ID to the existing core and started to ...
by dentnz
Fri Jan 22, 2021 4:29 am
Forum: SNES
Topic: MSU-1
Replies: 53
Views: 11131

Re: MSU-1

I've manually merged a reasonably new set of MSU-1 code into the latest master code. It compiled, but am yet to test. I'd like to tidy it up and maybe see if I can get the audio side of it into the main branch.
by dentnz
Thu Jan 21, 2021 10:32 pm
Forum: Commodore 16, 64, VIC-20
Topic: Super CPU Support?
Replies: 14
Views: 1250

Re: Super CPU Support?

Overclocking the CPU is entirely possible, however the SuperCPU has some additional advantages relating to RAM and being able to address more of it as a 16bit CPU. That said, overclocking the existing CPU is the first thing I looked at: I attempted to update the T65 CPU to be 20mhz, but the way the ...
by dentnz
Thu Jan 21, 2021 7:15 am
Forum: Commodore 16, 64, VIC-20
Topic: Super CPU Support?
Replies: 14
Views: 1250

Re: Super CPU Support?

Seems that the T65 implementation (the CPU of the current c64 core) is actually capable of being a 65C816. Need to generate a new clock pulse for the 20 Mhz somehow (the PLL already has 3 setup and could potentially clock divide the 1mhz into 20), but it might be possible to change the mode of the C...
by dentnz
Thu Jan 21, 2021 6:11 am
Forum: Commodore 16, 64, VIC-20
Topic: Super CPU Support?
Replies: 14
Views: 1250

Re: Super CPU Support?

Should be noted that the CPU that get's used in the SuperCPU is the 65C816... which happens to be already implemented in the SNES MiSTer core ;) https://github.com/MiSTer-devel/SNES_MiSTer/tree/master/rtl/65C816 More information here: http://mclauchlan.site.net.au/scott/C=Hacking/C-Hacking12/cmdcpu....
by dentnz
Thu Jan 14, 2021 10:36 pm
Forum: SNES
Topic: MSU-1
Replies: 53
Views: 11131

Re: MSU-1

MSU-1 won't happen on the official normal SNES core unless someone forks the SNES core and rips out all the addon chips and makes a SNES-MSU-1 separate core. The core is using 90% of the FPGA's space basically as is, without MSU-1. It's the second largest behind ao486. Not necessarily. It's entirel...
by dentnz
Sun Sep 13, 2020 11:20 pm
Forum: Commodore 16, 64, VIC-20
Topic: Anyone working on the 1750 (-ish) REU?
Replies: 4
Views: 1372

Re: Anyone working on the 1750 (-ish) REU?

The issue will be around how the RAM itself will be implemented. If we had enough FPGA space, then it would be pretty straight forward. The obvious alternative is to use the SDRAM instead, but the complexity is a bit higher and I am not sure about the latency of reads and writes.
by dentnz
Sun Sep 13, 2020 11:14 pm
Forum: X68000, PC88, PC98
Topic: X68000 beta - Updates and releases
Replies: 206
Views: 42888

Re: X68000 beta - Updates and releases

Ah, done!
by dentnz
Sun Sep 13, 2020 11:13 pm
Forum: X68000, PC88, PC98
Topic: X68000 beta - Updates and releases
Replies: 206
Views: 42888

Re: X68000 beta - stopped working all of a sudden

I'd love to change the subject of this thread to just be X68000 beta... Any idea how I can make that happen?
by dentnz
Tue Jul 14, 2020 11:27 pm
Forum: Linux
Topic: [Feature Request] Support for Linux-side Interfaces
Replies: 10
Views: 2809

Re: [Feature Request] Support for Linux-side Interfaces

Would a possible work-around be to use the existing bootrom functionality?

You could:

1) Copy the rom you want to boot to bootrom (for NES core: `boot1.rom = NES Cart file. Can be used with boot0.rom (BIOS) in place`)
2) Start appropriate core
by dentnz
Fri Jun 12, 2020 9:43 am
Forum: X68000, PC88, PC98
Topic: PC98 Core
Replies: 178
Views: 19506

Re: PC98 core

Sounds awesome @puu!!!! Having more space on the de10 and using the ao486 cpu things will be helpful I am sure! Keep us posted! Do you have a Patreon?
by dentnz
Wed Jun 10, 2020 11:12 pm
Forum: X68000, PC88, PC98
Topic: PC98 Core
Replies: 178
Views: 19506

Re: PC98 core

@puu have you got a build of PC98 core so far?
by dentnz
Sun Jun 07, 2020 4:28 am
Forum: X68000, PC88, PC98
Topic: X68000 beta - Updates and releases
Replies: 206
Views: 42888

Re: X68000 beta - stopped working all of a sudden

suverman wrote: Sun Jun 07, 2020 3:39 am Is MIDI output possible easily at this stage on the core? Midilink on MiSter is pretty incredible :)
Don’t see why not... be good to sort out 15khz video output... 24khz down to 15khz would also be nice somehow?