Recent posts

#1

Technical support - Hardware related / Re: CPC464 keyboard problem

Last post by TotO - Today at 22:17

I think that is not usual to have a faulty or weak RN into the IC, but sure, if you have the room for that...
That cost nothing to have the footprint.

#2

Technical support - Hardware related / Re: CPC464 keyboard problem

Last post by ikonsgr - Today at 22:11

As I know, the pull-up resistors are embedded into the AY-3-8910.

Well, same is for 8912, but unfortunately it didn't work with my CPC464 (still needed external pull-ups) , so it's better have it that too as an option, don't you think? 

#3

Games / Re: Could "Turrican" be made b...

Last post by andycadley - Today at 21:37

What tricks could you try to enlarge the game window with the same or better framerate?

- Use screen 64 byte in width (32 x 32 characters in MODE 1, but here MODE 0 would probably look more nice)
- Use CRTC characters only 4 scanlines high, or even better only 2 (instead of 8 like usually), this will make the scrolling more smooth, also gives extra time, because less V-RAM needs to be moved.
- instead of having sprites as data, use something like CoData (I use that for Filmemacher). Basically a program which draws the sprite or graphic element on screen. That's more quick compared to copy data.
- Use more RAM, this enables to unroll routines which contain loops. Also a speed up.

And finally: Do a complete rewrite instead of patching / enhancing / bettenering / etc. of an existing program. Alcon 2020 may serve as a well example for that ;-)

Excuse my ignorance but on
"Use CRTC characters only 4 scanlines high, or even better only 2 (instead of 8 like usually), this will make the scrolling more smooth, also gives extra time, because less V-RAM needs to be moved."
How does that make scrolling smooth? The CRTC has a fixed number of cycles to read the ram separately to the Z80, so how does reducing the character scanlines improve performance if its still a full screen(32x32)?
The CRTC is still working outside of the Z80 for screen refresh so I don't understand the comment.

The regular character line height is 8 scan lines. So you need to transfer data for 8 scanlines every frame in case you want to scroll up or down.
In case you use only 2 scanlines, then you only need to transfer 1/4 of the data. In addition scrolling is more smooth and slower.

Wouldn't that also make the screen 1/4 height? Or am I missing something?

#4

Technical support - Hardware related / Re: CPC464 keyboard problem

Last post by TotO - Today at 20:53

so i'm thinking of creating an adapter to be able to plug the much cheaper ay-3 8910 (i find it on ebay for ~3euros...)
Since this chip is relatively easy to be damaged (because of the direct connection to the joy port), i think it might be a good idea, what do youthink?

Nice idea.
As I know, the pull-up resistors are embedded into the AY-3-8910.

#5

Emulators / Re: CPCEC a new emulator from ...

Last post by TotO - Today at 20:50

Ideally, the package should include the sources and docs, nothing else; it would be the user's task to compile the binaries and to bring his own firmware files.

And nobody will use it.

The problem is to have mixed the CPC/ZX/C64 emulators into your CPC emulator.

#6

Games / Re: Could "Turrican" be made b...

Last post by chinnyhill10 - Today at 20:44

I've taken a photo of the screenshot from my own collection of AA magazines, and the player sprite does indeed appear blue instead of green.

Just keep in mind that screenshots provided to magazines can be mock ups rather than functioning code. Most infamously Sinclair User reviewed Nemesis with mocked up development screenshots that were nothing like the game. That screen could just be a picture thrown together in DPaint or something and the colours got changed as the assets were moved across.

#7

Technical support - Hardware related / Re: CPC464 keyboard problem

Last post by ikonsgr - Today at 20:17

Ok,i just finished the board! 

You cannot view this attachment.

Dimensions are roughly 5cmX3cm and i used interleave placement in order to save space. If anyone wants to give it a try, i can send him the gerber files! 

#8

Other retro / Re: Area 5150

Last post by ralferoo - Today at 20:15

Turns out CGA has a 6845 CRTC, so there's quite a bit in common here with demos on the CPC. It's a type 2 though (edit: just noticed ralferoo mentioned this already...)

I was hanging out with cTrix while he was composing the credits tune for this, it's a banger. Player is writing out a single sample per scanline, and the pc speaker hardware is only supposed to be a beeper!

Hadn't thought of that, but would make sense as it'd be a single bit at 15kHz.

> edit: just noticed ralferoo mentioned this already...

Heh yeah, one of the coders of this is in our demo group and we used to chat about the 6845 a lot.

#9

Technical support - Hardware related / Re: CPC464 keyboard problem

Last post by Bryce - Today at 20:02

You just need to wait long enough for a good offer to turn up and grab them all. I got a lot of 20x AY-3 8912 for €6 per chip a few months ago. Unfortunately I fix a lot of stuff (other than CPC too) that use these so I probably only have 1 or 2 left over at this stage.

Bryce.

#10

Emulators / Re: CPCEC a new emulator from ...

Last post by AmatCoder - Today at 19:54

Thanks for answers.

So package (source tarball) could contain the ROM files but they cannot be embedded (firmware also is executable code after all...)
It's a pity because it would have been more comfortable for the end user .

By the way (and getting back on topic) I want report a possible bug:
The game "007 The Living Daylights" is flickering with last versions of CPCEC (with CRT type 1).