Diy Usb Host Project

[nubie]

Here are some pics of my Home-made USB host cable.

This is the complete beta unit (you don't want to see the Alpha model :wacko: :blink

Start with a Simple USB motherboard header from the local PC store, Ebay, or your junk drawer, in order of descending price .

Use the ubiquitous Samsung e810 Serial Data cable (ebay, or a webshop)

Then you need to breadboard a simple filter circuit: http://wiki.gp2x.org/wiki/Image:Bob_usb_filter.png, 4 resistors, 2 ceramic capacitors.

The brown ones are R1 and R2 the 33 Ohm resistors, the blue ones are R3/R4 the 15K (15,000 Ohm)

The saucer-shaped components are the Capacitors, C3 and C4 .

The Bus connections on the back of the breadboard.

I have been able to connect all 4 devices at once to the hub, run PSX ISO's off of an 80GB HDD, copy from one USB stick to another (it's slow), play mp3s off of the Kingston 64mb stick, use a mouse in Qtopia and X11.

As for the specifics, I think radio shack only has certain sizes of ceramic Capacitors, you can use any size, I believe I used 100s, it is just to keep the data lines clean. The breadboard is $3 or so and the Resistors come in different sizes as you see.

I will field whatever questions I have the answer to, keep in mind I sold my GP2X a few months back and will be going from memory, I do recall posting back then on what precisely was working, so you can search my old posts.

The circuit can be made much smaller, there are even integrated circuits smaller than 5MM that can do all of this, they are about 50 cents from mouser.com or digikey. A power supply isn't even needed if you have a powered USB hub that will power everything. The AAA batteries I am using are NiMH rated at 1,000Mah whatever that is worth, they work Mice and USB sticks just fine.

 

[nubie]

The entire filter circuit is in this single 5-pin IC
http://catalog.digikey.com/scripts/partsea...e=497-3742-1-ND

It is $1.35 in single quantities, much cheaper in larger orders.

External dimensions are 2.2mm x 1.35mm x 1.1mm The Datasheet is here:
http://media.digikey.com/PDF/Data%20Sheets...FS/USBDF02W.pdf

Still boggles the mind as to why these aren't already onboard the GP2X, unit price on 500 is under $0.60, and that is from a end-user supply house. But they can also easily fit in the molded/shell end of a EXT or USB connector, power supply optional or external.

Second point, the GP2X power supply chip is fully customizable to 4 different output voltages, the 2nd editions are making 5 volts right now, still no idea what they were thinking with that EXT connector, they must just love the stupid things.

Not too hard to fix on your own, if all you want is USB, don't spend $$ on whatever Breakout Box they think is a viable solution. Video and Serial are simple to add to the DIY plug, they don't even need a termination circuit or a power supply, just wires.

 

[LordFu]

Thanks for the info, guys. So, I can order that part you link, nubie, instead of making the circuit myself? If that's true, I'm going to give this a try. I'm competent enough to solder a few wires up, I think. I've got an origianl-style tv-out cable, that has all the necessary pins.

 

[nubie]

Thanks for the info, guys. So, I can order that part you link, nubie, instead of making the circuit myself? If that's true, I'm going to give this a try. I'm competent enough to solder a few wires up, I think. I've got an origianl-style tv-out cable, that has all the necessary pins.

That is the idea, the original cable would be perfect. I hope you have experience with mod-chips and some really thin wire .

I suppose you could design a circuit-board for the chip, or glue it to something and use conductive pen.

Edit: just went back and searched "usb term" at digikey, you want the ones that end in W5, note some are minimum 3,000 piece order. Can't link right now because their website is "updating".

 

[aapje89]

Hmm, nice tutorial .

But nothing for me, I tried to mod an ericsson keyboard for the gp32 some years ago, and I failed miserably

 

[chunkyktr]

nice, very nice

thanks nubie

 

[cowai]

Make a kit and sell it.

 

[GeminiDomino]

Very nice.

Am I correct in understanding that the EXT connector on the original TV-OUT connector has all the necessary pins, not just the ones needed for the video output? That could save me the headache of finding another connector (managed to utterly destroy the last one...)

 

[cowai]

Thinking of making this a kit, if you just polish it a bit more? Maybe just a cable with usb and tv-out.

 

[nubie]

Very nice.

Am I correct in understanding that the EXT connector on the original TV-OUT connector has all the necessary pins, not just the ones needed for the video output? That could save me the headache of finding another connector (managed to utterly destroy the last one...)

The first batch of the TV-Out cables has all the pins, it is easy to see them in the end of the connector, there will be an unbroken line of little copper-colored contacts from one side to the other.

Unfortunately, the first batch also didn't fit quite right and you needed to hold the connector in, or jam a piece of paper in along with the plug.

 

[danny_galaga]

Make a kit and sell it.

yes, yes KIT! KIT!

 

[nubie]

Make a kit and sell it.

yes, yes KIT! KIT!

Unfortunately I don't have a GP2X anymore, but I recently purchased repaired and modded my first Xbox. LG 8164 16x DVD-Rom drive and 80GB WD HD with a softmod, oh and a Component to VGA cable with the softmod for my HT projector.

That got me thinking about a way to raise money with my soldering/modchip skills. One option that came to mind is a GP2X internal USB mod service that I could offer.

The main portion of the mod would be a little circuit board that has the USB chip on it and 4 wires running internally to the GP2X motherboard. I was thinking of making a circuit where the USB could be externally powered, perhaps by 4 NiMH AAA's "grip-style" screwed into the back, or 2 AA/AAA size Li-Ions, grip-style or above the existing battery pack.

The main problem is that I am attending school and have enough debt to feel it, and I won't go in any further to make a product. I am fine with performing a service, or selling previously modded/used items I own. I guess I should buy a GP2X and do a mod, then I can sell it .

I guess some double-sided sticky tape would hold on AAA battery packs and a 4-port USB hub , so I could make an external mod connected to the EXT, I would just need another GP2X (it would be the 4th I have owned, I am fickle, and my first one was the F100 brick-o-matic), and some circuit board stuff, I have never made a circuit board.

I suppose I could just get a TV cable and super glue the USB chip to it and have a go with my mod-chip wire , but that would be too much fun. As I say, the fancy doesn't strike me at the moment, and the Xbox360/Wii/Geforce8800 320MB are vying for an increase in my debt in the next couple of months, or at least a nice chunk of my grant money or next paycheck. The GP2X is okay, and I must admit the Descent remake and the thought of testing pico-drive are very tempting, not to mention the HDR version of Payback, much as I detest the genre, the tech shots are making me drool.

I might be tempted to do the super-glue/TV-cable thing and take some pictures, but borrowing the camera is such a hassle and I don't have a proper work-bench. Don't get your hopes up.

 

[nubie]

Make a kit and sell it.

yes, yes KIT! KIT!

snip (OMG I typed a lot!)

Good news, I ordered a USB terminator chip. $0.79 apiece in quantities of 1-10. ($6.34 for 10 of them)

http://catalog.digikey.com/scripts/partsea...e=497-3086-1-ND

Orders under $25 tack on $5 handling charge, I don't know if I am going to get hit with tax, they are in MN, and I chose First Class Post, for $2.04, hmm I am feeling cheap.

I got a 15watt soldering iron and I have some really nice modchipping wire . We shall see!

I don't have a way to test it, but I have the working prototype and it should be a simple thing to connect 5 wires. At least a nice picture tutorial of the right way should come out of it.

EDIT:I got the super micro chip from Digikey.com (USBDF01W5 part# 497-3086-1-ND), here is a picture of it mounted to a Radio Shack breadboard. And a shot of it on a dime, these things are really small.

To mount it you need to get four seperate solder pads to converge, either cut two lines and put this chip across the cut, or cut one line next to two others, as I did here. Then.

1. Bend up the middle leg, lay the chip on its back and press carefully on the middle leg, you don't want it to break.

2. Put it in the middle of 4 seperate bus strips, Hold it down while you solder to the first pad with a 15 watt iron. (I didn't and the surface tension of the solder sucked the whole chip right into the hole, and then it stuck to the iron. But hold it down and it will work.)

3. Then do the one opposite and then the last two.

4. Finally connect the ground wire to a seperate bus strip, I used 30 AWG wrapping wire from llama.com, they sell 1 foot each of 10 colors for $0.99, it looks crappy, and there is a chance of ripping off the ground leg.

I checked the ground against all four lines and I got 15 ohms resistance, I guess that means I didn't overheat the chip and I got the ground connected well.

So if you need the termination circuit and want to do it right, here it is. I hope that someone who knows how to do it properly will tell us how, AKA etch a little board, use some powdered solder, bake in the oven to a precise temp, then raise it quickly and solder will flow. I have never done it, I suppose I should start, it might be easier/better than this way.

If someone is going to do it the right way, you might as well make the circuit for the Samsung e810 to replace the current board, and put some traces and a socket or pads for the A/V out (think handycam video cable) and/or Serial (Jtag too is possible). It shouldn't be too hard to etch that into a board for testing purposes.

 

[nubie]

If someone is going to do it the right way. . .

Here is a link to surface soldering in a toaster oven:

http://www.seattlerobotics.org/encoder/200006/oven_art.htm

All we need now is a how-to on making a printed circuit board. If we make it the same size as the Samsung e810 board (http://wiki.gp2x.org/wiki/Image:Ext-bottom.jpg) then we could simply replace that board with our custom one.

Solder pads should be enough for A/V S-video and/or Composite besides the USB host. That way the USB filter is built into the plug and you are good to go.

Also, if you are really brave you could find some unused pins (USB Device 1.1?) and connect them to the 5 volts inside the GP2X so that mice/flash mem etc could be used without additional power (Not portable HDD or Wifi).

 

[TJHooker]

I suggested a ASIC/IC, and a LiPO pack in another thread. Using a small NiMH specialty cell would be better than LiPO though because of the LiPO tendency to create voltage spikes when it needs charging.

It be cool if GP put the current one in a injection molded case. Having components exposed isn't too practical for a end user solution; especially when it's for a hand held gaming device.

 

[firefly2442]

The DigiKey link for the filter circuit looks like it is obsolete. Is this the same thing?

http://www.digikey.com/scripts/dksearch/dk...&Row=220939

 

[DIEGO MOTA]

I´d like to know if can I use your home-made USB host cable to connect a microchip to a keyboard? If not, do you know any USB host cable which can do that?