Psx4gp2x Beta Testers Thread

[Fishbong]

It would be great to do a voltage mod for the GP2X. I would imagine more people would be able to reach some of the higher overclocks we've seen with it. For instance, I was able to change the voltage on my Sharp Zaurus C1000 to 1600mv and got a 624MHz overclock stable over the 1500mv 514MHz.

Maybe Squidge can do a voltage mod? How hard of a job would it be?

Its not that hard for a professional, i´m surprised noone did this yet. All you gotta do is find the stepdown converter chip. Usually they are adjustable via two resistors. Find some datasheet for the stepdown chip, locate the two resistors in question and change them to increase the voltage.

I used stepdown chips in some home projects, and they are really simple pieces of hardware. I was using the LM2576 chip, have a look at its datasheet, its really simple.

 

[mattyrb]

I can't help but think over clocking a hand held is a little pointless. You want the batteries to last as long as possible not be completely drained by pushing the CPU further.

 

[Vimacs]

i prefer playing 30 minutes (out of about 5-6hours) shorter but with 50fps over playing 30 minutes longer at 30fps.

 

[Squidge]

i prefer playing 30 minutes (out of about 5-6hours) shorter but with 50fps over playing 30 minutes longer at 30fps.

My feelings exactly

Unless of course your DaveC, in which case at 50fps your batteries apparently last about 30 minutes

 

[zodttd]

Fishbong, the data sheets you're looking for are:
mp2520f data sheet.pdf

This might also be of use:
MP2520F_Manual_Eng_V1.0.pdf
As it also contains the data sheet from what Im aware of.

I opened up my GP2X, and next to the CPU with the thermal pad, I see the resistors in question... at least I think. To "switch" the resistors, what is required? How would you go about increasing or decreasing voltage by a set amount?
I don't plan on trying this out until I'm sure I know what I'm doing, which I have no clue right now.

 

[Paradox]

i dont care how long the batteries last under 50FPS PSX emulation as i'll most likely just be hooked up to an AC anyway. along with my breakout box, 2 gamepads and 200gb external hd.

 

[Drak]

i dont care how long the batteries last under 50FPS PSX emulation as i'll most likely just be hooked up to an AC anyway. along with my breakout box, 2 gamepads and 200gb external hd.

Whats the point of buying a handheld then?

 

[moz]

i prefer playing 30 minutes (out of about 5-6hours) shorter but with 50fps over playing 30 minutes longer at 30fps.

My feelings exactly

Unless of course your DaveC, in which case at 50fps your batteries apparently last about 30 minutes

not to split hairs DaveC is from the US so only ntsc 60fps will do?

 

[Paradox]

i dont care how long the batteries last under 50FPS PSX emulation as i'll most likely just be hooked up to an AC anyway. along with my breakout box, 2 gamepads and 200gb external hd.

Whats the point of buying a handheld then?

its not the handheld aspect of it which is why i bought it. if there was an open source linux console with such a big homebrew community i'd have bought that too. but being a handheld is just cooler anyway.

 

[grahf]

Yeah, much easier to show off to your friends

 

[DaveC]

i prefer playing 30 minutes (out of about 5-6hours) shorter but with 50fps over playing 30 minutes longer at 30fps.

My feelings exactly

Unless of course your DaveC, in which case at 50fps your batteries apparently last about 30 minutes

No you lie.. My batteries last 38 minutes

Fishbong, the data sheets you're looking for are:
mp2520f data sheet.pdf

This might also be of use:
MP2520F_Manual_Eng_V1.0.pdf
As it also contains the data sheet from what Im aware of.

I opened up my GP2X, and next to the CPU with the thermal pad, I see the resistors in question... at least I think. To "switch" the resistors, what is required? How would you go about increasing or decreasing voltage by a set amount?
I don't plan on trying this out until I'm sure I know what I'm doing, which I have no clue right now.

Yeah don't mess with it. It is not always so simple, it may be part of a voltage divider circuit and by changing one voltage you can screw another one up. Electrical components work by having magic blue smoke in them, If you let some blue smoke out it won't work anymore

 

[kardasan]

blue smoke you say? What were you smoking today?

 

[Nr.56]

i think dave would say that voltage goes sometimes not the way you imagine. the risk of a hardwarekill is high even the cpu is able to reach 350mhz. but their are a lot of parts wich have to resist against the higher voltage. i´m interested how long such a modified gp2x works. if someone make this modifikation i want to see a video with the results in fps.

PS: your gp2x runs really 5-6 ours with one akkupack ????

 

[icurafu]

when I tested this emulator, mhz had a linear increase against FPS which seems to plt towards (0,0).

I don't see why it would stop. It's be easy to make a graph.

 

[Nr.56]

it is true. the gamespeed increase proportional to the cpu-speed. but isn´t it to easy to manipulate the hardware to get a playable framerate? the meaning of such a device like the gp2x is make software for this device. know about the hardwarelimitations and live with it. code the software and optimise it till its work. not like commercial computerproducts: if you want to play it, buy a new computer every year or a new graphikcard. zodttd (and his team) was on the right way. now finish it. this emulator could be a killeraplikation for our handheld. i waiting for a oportunity to test the new version.

PS: maybe i would try it, but not every owner is able to tweek his gp2x!

 

[Paradox]

I found this: http://www.techfocus.co.uk/silver-usb-dual...CFQ-IQgodQGLsRA

a USB gamepad like a PSX pad..would be perfect for playing with gp2xpsx, would it work with a breakout box or do we need opensource drivers or something?

 

[lintsniffer]

www.retrousb.com

 

[icurafu]

it is true. the gamespeed increase proportional to the cpu-speed. but isn´t it to easy to manipulate the hardware to get a playable framerate? the meaning of such a device like the gp2x is make software for this device. know about the hardwarelimitations and live with it. code the software and optimise it till its work. not like commercial computerproducts: if you want to play it, buy a new computer every year or a new graphikcard. zodttd (and his team) was on the right way. now finish it. this emulator could be a killeraplikation for our handheld. i waiting for a oportunity to test the new version.

PS: maybe i would try it, but not every owner is able to tweek his gp2x!

I'll do a scatterplot and regression of the results on the weekend, or when the next beta release comes out. That could give us an idea of what we need to get 50fps.

 

[lintsniffer]

<vader nooooo>
My last day of school is today (<2 hours) please don't remind me of Algebra II, PLEASE!

 

[Fishbong]

Fishbong, the data sheets you're looking for are:
mp2520f data sheet.pdf

This might also be of use:
MP2520F_Manual_Eng_V1.0.pdf
As it also contains the data sheet from what Im aware of.

I opened up my GP2X, and next to the CPU with the thermal pad, I see the resistors in question... at least I think. To "switch" the resistors, what is required? How would you go about increasing or decreasing voltage by a set amount?
I don't plan on trying this out until I'm sure I know what I'm doing, which I have no clue right now.

Nah, you got me wrong, the datasheet of the proc is not useful for making a voltagemod (apart from finding out the max safe voltage).

The MP2520F runs on 1,8V. That means there must be a small IC with 6 or so pins on the board, which steps the battery voltage (2,4V - 3V) down to 1,8V. The trick is locating and itentifying the IC, everything else is most probably described in its datasheet.