DogTag
Offline
Murcia, Spain

Hello guys!

I have decided to make a half clock mod in a DMG, and so I was wandering around different websites.
I know that the crystal should be 2.097152Mhz, but apparently in most electronics stores this is not a way of "identifying" them. I've come across this website, which has some claiming to be "2 Mhz":
http://es.farnell.com/iqd-frequency-pro … dp/9712690
http://es.farnell.com/multicomp/hc49u-2 … dp/1666945
http://es.farnell.com/raltron/a-2-000-1 … dp/1386656

Those are some examples.
So I wanted to ask you if you knew these will work, or if you know of an specific model/company/shop selling one suitable for this mod.
Also it'd be good to know a nice website for buying electronics stuff with good international shipping rates (I'm spanish) : D. I mean plain electronics, not just Arduino/robot related stuff (of which I already know several).

Timbob
Offline

You can use a 2mhz crystal and the gameboy will run almost half as slow.

But the problem is that your songs will sound out of tune. Since the gameboy uses the clock speed to determine the pitch.

For example. A C4 note at half speed will be a C3
The problem with a 2 MHz clock is that a C4 will be just a little lower then a C3 that way.

Which could be interesting tho big_smile
And you can fine tune instruments in lsdj, but that's a lot of workaround.

So in short. Yes a 2mhz crystal will work, but your gameboy will be out of tune.

DogTag
Offline
Murcia, Spain

That's what I was thinking myself, but wasn't sure, as I've never treated with these componentes before : S

So I definetely need a 2.097152Mhz, because I want the DMG to be "concert tuned". Now, do we have any tips on where to get those?

nitro2k01
Offline
Sweeeeeeden

You can use that crystal if you want. They will work and LSDj will run, but apparently the frequency is slightly too low. This means that the notes played will be slightly too low in pitch. However, there's a way around this. You can change the frequency table in LSDj to make it work correctly with essentially any crystal oscillator speed.

Explanation of the oscillator frequency used in the Gameboy: It is using frequency that is a power of 2, so the frequency is (nominally) 2^22 Hz, or 4*1024*1024 Hz. This can also be called MiHz, or MibiHertz. -> http://en.wikipedia.org/wiki/Binary_prefix
Why Nintendo did this, nobody knows for sure.

DogTag
Offline
Murcia, Spain

By changing that, would then the "Normal" notes be too low in pitch?. The idea was to install a switch so that I can dinamically change between half and normal clock.
I've found one on mouser:
http://es.mouser.com/ProductDetail/Fox/ … 7nM%252btM

But the price seems a bit high... isn't it?

little-scale
Offline
ad-hell-aide

Of interest maybe (tuning table etc): http://little-scale.blogspot.com.au/200 … e-boy.html

Timbob
Offline
nitro2k01 wrote:

You can use that crystal if you want. They will work and LSDj will run, but apparently the frequency is slightly too low. This means that the notes played will be slightly too low in pitch. However, there's a way around this. You can change the frequency table in LSDj to make it work correctly with essentially any crystal oscillator speed.

Explanation of the oscillator frequency used in the Gameboy: It is using frequency that is a power of 2, so the frequency is (nominally) 2^22 Hz, or 4*1024*1024 Hz. This can also be called MiHz, or MibiHertz. -> http://en.wikipedia.org/wiki/Binary_prefix
Why Nintendo did this, nobody knows for sure.

Hmm, does this mean you could half-clock a gameboy without changing the crystal?
Theoretically speaking.
Divide the whole frequency table by half.
Or does a normal clock prevent a gameboy to play notes lower then the lowest notes in lsdj.
Hardware restrictions and all.

nitro2k01
Offline
Sweeeeeeden

Exactly right. You've only got a fixed range of frequencies. However, a straight half frequency means the pitch is one octave lower, which is never a problem. The problem is when you have an oddball ratio, so the pitch is almost, but not quite, one semitone off an nothing works together.

ashimoke
Offline
Czech republic
DogTag wrote:

The idea was to install a switch so that I can dinamically change between half and normal clock.

Gameboy will crash most of the times you switch between 2 crystals. Normaly you have to do this when it's turned off. Kitsch had great item called easy_CLK in his store which makes it possible to switch between normal and half clock while the gameboy is running. It's labeled "coming soon" on his website.

nerdsome
Offline

To dogtag, how many crystals you need. I think I have 1 or 2 spares.

DogTag
Offline
Murcia, Spain
ashimoke wrote:
DogTag wrote:

The idea was to install a switch so that I can dinamically change between half and normal clock.

Gameboy will crash most of the times you switch between 2 crystals. Normaly you have to do this when it's turned off. Kitsch had great item called easy_CLK in his store which makes it possible to switch between normal and half clock while the gameboy is running. It's labeled "coming soon" on his website.

Oh my, thanks that you said that! I'd have installed it just with a switch, to later find the problem myself... That's why I like to ask before doing anything xD

So I'll have to wait until Kitsch gets that back in stock.
Seriously, thank you for all the hassle, you've saved me from xD

And the table tuning is quite an interesting thing to have bookmarked. Thanks guys!

DogTag
Offline
Murcia, Spain
nerdsome wrote:

To dogtag, how many crystals you need. I think I have 1 or 2 spares.

We overlapped!

Because of what ashimoke said, what I actually need is that easy_CLK from kitsch, because I want to be able to switch crystals with the DMG turned on. But thank you very much for the offer!

nerdsome
Offline

Guess I should have read everything.  You can still install a half clock switch without the kitsch kit. Just takes more space. I want that kit too but he is out so I'm doing it the old school way.

DogTag
Offline
Murcia, Spain
nerdsome wrote:

Guess I should have read everything.  You can still install a half clock switch without the kitsch kit. Just takes more space. I want that kit too but he is out so I'm doing it the old school way.

Watch out, ashimoke pointed that if you do it that way the GB will crash.

nerdsome
Offline

It crashes if you switch it while it's on.  I don't plan to do that.  I've installed half clocks with a switch before and sold them with no complaints. With the kitsch kit, I believe you can switch it while playing a song but I'm not sure. That would be convenient but for me, it's not required.

ashimoke
Offline
Czech republic
little-scale wrote:

Of interest maybe (tuning table etc): http://little-scale.blogspot.com.au/200 … e-boy.html

I guess it is possible to use similar trick to "half clock" LSDJ in software. Has this been done? I'd be interested...