i got a great idea....


quit fucking around with game boy technology and use a plug in if you want crystal clear square waves..
otherwise.. deal with the signal to noise ratio and just make music.

I see people go back and forth on the output modification argument and it's like.. why? it's a 20 year old game boy. deal with the noise or move on and use an emulation plug-in.

packing all these stupid concepts into old technology is stupid.  The effort involved isn't worth the small change in the end result.  So you might as well just get over the noise... get over the "lack of frequency response" and just concentrate on the important things... THE MUSIC

I'm not dissing the pcb design or anything like that.. it's the argument over the audio quality, etc. IT'S A GAME BOY. lol.

Last edited by low-gain (Sep 6, 2010 5:47 pm)

low-gain: OR make a really really easy modification and get rid of the noise, and be happy with it. Someone apparently can't stand losing an argument.

NeX wrote:

if you are willing to work together, i can give you a rough design of an LCD PCB that would include a pocket screen, maybe a second arduino for RGB control or other things,

i have no experience with designing circuit boards, so i will just be drawing it out by hand and you would have to do the digital version.

like i said before, this is great work, i think if you can loose the bootloader header and maybe fit some extra big SMD caps too, i will try and get that arduino code tested,

Hit me up on Google Talk and we can discuss the LCD PCB. smile

The headers may or may not be temporary. I could program the ATmega before it goes on the board, but that complicates things, and I'd need to get a TQFP-32 ZIF socket, which isn't cheap. There's room for bigger caps, so that will likely happen in the future.


kitsch wrote:

if you need any assistance with PCB design, let me know.

since you are in EAGLE, i'm pretty proficient...  learning altium designer made eagle cad a cinch...  well, apples and orange, but altium can be like pulling teeth compared smile

but, yeah, if you need any advice/assistance, please let me know.  i'm happy to help how i can.  including the grounding plane issue.  which, tbh, is going to be an issue the way eagle handles this and the board is laid out. 

this goes to Rolf and Nex in particular, but to anyone else really.  i don't mind helping out with eagle.  its pretty fun honestly. 

also, be careful in eagle because the free version's license has some caveats concerning the making of things to sell.  the free version is meant for hobbyists really, not for commercial application.  last time i checked, they offered a single license thing to get past this...  but i don't know the cost.  altium ended up being substantially cheaper and more powerful for me personally...

i'd try to talk you out of eagle, but its too late wink

edit -- also, many of the eagle libraries are licensed as well, including the sparkfun one the last i checked (try the adafruit one instead).  meaning, you shouldn't use their footprint/silkscreen/etc...  i always make my own footprints in eagle though, except for caps and resistors really, and can help with this also.  or, can walk you through the basic process of doing this.  its pretty horrible the first couple times, but becomes very easy after you figure out what it is you are doing...

Thanks for the offer for help. I'll get a hold of you if I'm ever stuck with anything.

EAGLE is missing some pretty important features, but for the most part, I like how simple it is. I tried Altium for a little while, but I didn't really like it. I can see how it would be better for someone more serious about PCB design.

nitro2k01 wrote:

Arfink: Picking up noise from address lines: Marginal problem. Insofar that this is a problem, it can be improved by tapping ground off of a location near where you tap the signals.

The ESD argument... No, just no. If you want me to elaborate on why this isn't a problem, I could.

I guess my approach is more coming from the modding-a-stock-DMG standpoint, not so much from the new motherboard. As for ESD, I am mainly referring to some kinds of DIY prosound mods which basically connect right up the CPU audio output pins, which to me is just something you shouldn't do out of the principle of the thing. In actual practice it's probably be OK, but I still wouldn't do it. Same for the noise issue, you can actually add more shielding/ground plane etc. with a new board, so why not.

As for the DC:DC, that's not some scare tactic, I'm just trying to be helpful. I know the DC:DC in gameboys is pretty cheaply made, and it does in fact add alot of noise. Furthermore, replacing the DC:DC would also provide the added benefit of making the gameboy more capable of handing things like EMS carts, backlights, arduinoboys, etc, which draw alot more current than the DC:DC is made to handle. Especially in the GBP this would help to reduce problems with screen dimming and catastrophic crashes due to overdrawing the converter.

Last edited by arfink (Sep 6, 2010 7:35 pm)

some of us like the noise from a gameboy  sad   and embrace it.

i used Zen Albatross's prosounded gameboy at PAX and hated it.

Logan I think you have mixed your personal opinion up with other peoples.

arfink wrote:

I guess my approach is more coming from the modding-a-stock-DMG standpoint, not so much from the new motherboard. As for ESD, I am mainly referring to some kinds of DIY prosound mods which basically connect right up the CPU audio output pins, which to me is just something you shouldn't do out of the principle of the thing. In actual practice it's probably be OK, but I still wouldn't do it. Same for the noise issue, you can actually add more shielding/ground plane etc. with a new board, so why not.

Sure. That's stupid, but not from an ESD standpoint. (In short, ESD hazards mainly affect digital inputs CMOS inputs, and not pure outputs.) The hazard there has more to do with accidentally grounding the outputs and frying them, which is of course bad in its own right. But I'm under the impression that this is not the most common may of doing a Prosound. Soldering to an SMD pin is more difficult than soldering to the potentiometer. And in the case of epoxy blob boys, you'd have to solder to a via on the board. I think most people do it the conventional way. And when doing it the conventional way, there's a 50 ohm resistor that adds some protection.

arfink wrote:

As for the DC:DC, that's not some scare tactic, I'm just trying to be helpful.

The scare tactic part was a response to the quoted comment by low-gain. smile

arfink wrote:

I know the DC:DC in gameboys is pretty cheaply made, and it does in fact add alot of noise. Furthermore, replacing the DC:DC would also provide the added benefit of making the gameboy more capable of handing things like EMS carts, backlights, arduinoboys, etc, which draw alot more current than the DC:DC is made to handle. Especially in the GBP this would help to reduce problems with screen dimming and catastrophic crashes due to overdrawing the converter.

Increased power consumption means increased ripple, true, but that can be solved with more decoupling caps. But the problem on the other hand is to get that -18V. My point is that a DMG with a Prosound is "good enough". Redesigning the DC/DC, which would be a hassle, is overkill if all you want is reduce the noise.

I think the main problem with GBP is the choice of battery type, (AAA instead of AA) not the DC/DC. Bibin did a modification where he used a Li-Po (IIRC) battery, which increased stability greatly. EMS carts are notorious though, because they have a design flaw which makes it eat more power than it should.

low-gain wrote:

i got a great idea....


quit fucking around with game boy technology and use a plug in if you want crystal clear square waves..
otherwise.. deal with the signal to noise ratio and just make music.

I see people go back and forth on the output modification argument and it's like.. why? it's a 20 year old game boy. deal with the noise or move on and use an emulation plug-in.

packing all these stupid concepts into old technology is stupid.  The effort involved isn't worth the small change in the end result.  So you might as well just get over the noise... get over the "lack of frequency response" and just concentrate on the important things... THE MUSIC

I'm not dissing the pcb design or anything like that.. it's the argument over the audio quality, etc. IT'S A GAME BOY. lol.

but maybe doing tech stuff like this is more fun and rewarding for people than writing songs is.

The things people do for their love of nanoloop/lsdj big_smile

herr_prof wrote:

The things people do for their love of nanoloop/lsdj big_smile

too true...

nitro2k01 wrote:

I think the main problem with GBP is the choice of battery type, (AAA instead of AA) not the DC/DC. Bibin did a modification where he used a Li-Po (IIRC) battery, which increased stability greatly. EMS carts are notorious though, because they have a design flaw which makes it eat more power than it should.

Yeah, that works because then if you overdraw the DC:DC it won't at least bomb out as soon as the batteries have a little voltage dip. I was just thinking, if you're making a new mobo for the DMG, it would be maybe a tad easier to deal with those issues. Again, all my suggestions are pretty much speculative and I'm just suggesting the way you'd do it for a really clean build that's probably totally overkill. Since we're in a thread about replacing the DMG mobo, I though it might as well throw it in there, since a new mobo is also probably overkill. smile

herr_prof wrote:

The things people do for their love of nanoloop/lsdj big_smile

this was a truly heartwarming observation! smile

I heart nanoloop and LSDJ! Big hugs all round, you arguing rascals! wink

The only reason to do anything with a DMG, especially overkill mods, is because:

IT'S AWESOME!

Keep up the good work, I hope to see this mobo get produced.

Last edited by arfink (Sep 6, 2010 11:00 pm)

Rolf wrote:

The headers may or may not be temporary. I could program the ATmega before it goes on the board, but that complicates things, and I'd need to get a TQFP-32 ZIF socket, which isn't cheap. There's room for bigger caps, so that will likely happen in the future.

my vote still goes for replacing link port with a usb and prgramming arduino through there.
besides, you want all sync data headed to the arduino anyway

I have an idea for how you might (mis)use the serial port for this. You have already have 3 functions that map well onto the ICSP header, SIN, SOUT and SCLK. A small trick using a resistor is needed for one of the signals, however. Then there's one unused pin on the link port, which you don't actually need to connect according to the DMG schematic. You can use this one for ICSP reset. You can make that a cuttable trace, since it's not needed anymore once the Arduino bootstrap is in place.

I do recommend keeping the other header, containing Gnd, Reset, and two way serial. This allows reprogramming using an external USB adapter that plugs into that header, via the Arduino software. To make this optimal, it might be a good idea to rearrange the use of some of pins on the microcontroller. This would be pretty easy in the Arduinoboy source code, but would improve some aspects of the design. Further polishing of the code to allow it to peacefully exist together with the link port might be a good idea.

I would not support a removal of the link port, though.

Will have to elaborate on my evil ideas later, though.

nitro2k01 wrote:

I have an idea for how you might (mis)use the serial port for this. You have already have 3 functions that map well onto the ICSP header, SIN, SOUT and SCLK. A small trick using a resistor is needed for one of the signals, however. Then there's one unused pin on the link port, which you don't actually need to connect according to the DMG schematic. You can use this one for ICSP reset. You can make that a cuttable trace, since it's not needed anymore once the Arduino bootstrap is in place.

I do recommend keeping the other header, containing Gnd, Reset, and two way serial. This allows reprogramming using an external USB adapter that plugs into that header, via the Arduino software. To make this optimal, it might be a good idea to rearrange the use of some of pins on the microcontroller. This would be pretty easy in the Arduinoboy source code, but would improve some aspects of the design. Further polishing of the code to allow it to peacefully exist together with the link port might be a good idea.

I would not support a removal of the link port, though.

Will have to elaborate on my evil ideas later, though.

I'll definitely be leaving the link port where it is, mostly for universal support of Game Boy linking and peripherals, but also because it looks nice.

I'm not sure about using the port for ICSP, simply because it's basically a one-time thing. On the other hand, perhaps an FT232 for USB communication with the Arduino could be adapted to work through the link port. If it could be done, it would make things a lot nicer for the end user to upgrade or develop for the onboard Arduino. Of course, that would only work if the link port was still fully functional as well.

I've already done a bit with the Arduinoboy code, but haven't been able to test it on a built arduinoboy, so I'm not sure if it works 100% correctly. I added a standby mode which only consumes 30-50% of the power of the other modes (I don't recall the actual number). I also fiddled around with the pin modes, and according to my logic probe, the pins which connect to the link port are neither high nor low when it is sleeping. Hopefully that will mean things like LSDJ sync will work fine when it's in standby mode.

Last edited by Rolf (Sep 7, 2010 5:27 am)