Easy Gp2x Serial Cable


sweetlilmre

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Hi,

Using info provided by Nubie:

I have written up some easy to follow (I hope :)) instructions on the Wiki, on how to build a serial cable using a Samsung E810 serial data cable (the one that has the built-in serial level converter).

I've built 2 of these and they have taken under an hour a piece to build!

You can find the info at: http://wiki.gp2x.org/wiki/SamsungE810Cable

Enjoy
-(e)
 

nubie

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Sweet, I am glad to have helped :)

That is one way to do it, I am hoping that his nice pictures will get someone to make a PCB for a breakout box once they see how the pcb is so easy to hook up on this one compared to the official one.
 

calqlater

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Thanks for the pics and tutorial!

I just got my E810 cables from AXShop, but haven't had time to rip them apart, yet. I'll probably be turning one into a straight serial cable, and breaking the other out into a breadboard header for prototyping a breakout board.
 

Flavor

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That looks pretty slick, but your write-up seems incomplete (or maybe just not verbose enough).

Why do you use the "single core" wire? You're just going to solder other wires onto those wires later, right? Why add any new wire at all? Couldn't you just move the existing wires from one location to another?

It would be really nice to show a picture of the whole cable before and after your mod. I've never owned or seen an E810 cable, and more pictures would be very nice for anyone who might be considering buying one to do this mod.

Wouldn't the pad that's right under the number "2" be easier to solder to than the pin you have labeled as "RX?"

It seems to me that you're just re-mapping pins from one device to another. It seems like you wouldn't have heat-shrink or anything like that if you just opened the shell, moved wires, closed the shell.

What am I missing?
 

nubie

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Flavor posted on Feb 21 2006 at 10:34 AM said:
That looks pretty slick at but your write-up seems incomplete (or maybe just not verbose enough).

Why do you use the "single core" wire? You're just going to solder other wires onto those wires later, right? Why add any new wire at all? Couldn't you just move the existing wires from one location to another?

It would be really nice to show a picture of the whole cable before and after your mod. I've never owned or seen an E810 cable, and more pictures would be very nice for anyone who might be considering buying one to do this mod.

Wouldn't the pad that's right under the number "2" be easier to solder to than the pin you have labeled as "RX?"

It seems to me that you're just re-mapping pins from one device to another. It seems like you wouldn't have heat-shrink or anything like that if you just opened the shell, moved wires, closed the shell.

What am I missing?

You are not missing anything, he just chose to do it the hard way.
If you want pics find my topic on the serial cables, there are pics on axshop.com if you follow the link in my posts there.

I personally believe it is better to use the original wires. That is what I did.

I tried to bump my topic but nobody was interested.
 
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Flavor

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Well, it's interesting to me, but I'm not sure if I need a serial cable if I can get a console via USB.
 

sweetlilmre

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Flavor posted on Feb 21 2006 at 07:34 PM said:
That looks pretty slick at but your write-up seems incomplete (or maybe just not verbose enough).

Why do you use the "single core" wire? You're just going to solder other wires onto those wires later, right? Why add any new wire at all? Couldn't you just move the existing wires from one location to another?

It would be really nice to show a picture of the whole cable before and after your mod. I've never owned or seen an E810 cable, and more pictures would be very nice for anyone who might be considering buying one to do this mod.

Wouldn't the pad that's right under the number "2" be easier to solder to than the pin you have labeled as "RX?"

It seems to me that you're just re-mapping pins from one device to another. It seems like you wouldn't have heat-shrink or anything like that if you just opened the shell, moved wires, closed the shell.

What am I missing?

Good point, I need some more explanation in the wiki, like:

1. When you remove the wires from the solder pad, they get a little messed up.

2. The wires are soldereded onto pads at the end of the circuit board, so getting them to stretch to the pins is difficult, especially if you have to trim them because of (1).

3. The single core wire has stiffness to its advantage, its actually a helluva lot easier to solder onto the pins (I made 2, one with multi-core and another with single core). Also for the un-solder-friendly, you can glue the single core wire to the board before soldering.

4. I'm a bit of a neat freak, when it come to electronics (probably because I don't really know what I'm doing) :) So using the single core wire allowed me to, very neatly, solder onto the pins, and extend onto the cable wire.

5. I could have soldered onto the pad for "pin2" but I want it all to be consistant.

I'll take a pic of the complete cable and assembly and u/l it later.

Thanks for the constructive comments, this should help me make a better wiki page!
-(e)
 
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slygamer

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sweetlilmre posted on Feb 22 2006 at 05:34 PM said:
4. I'm a bit of a neat freak, when it come to electronics (probably because I don't really know what I'm doing) :) So using the single core wire allowed me to, very neatly, solder onto the pins, and extend onto the cable wire.
If you're such a neat freak, you must have really freaked when you melted the bottom of the connector with the soldering iron. The photos show before and after shots. :)
 
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sweetlilmre

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I have updated the wiki with some more pics as requested and some editing.

slygamer posted on Feb 23 2006 at 12:38 AM said:
sweetlilmre posted on Feb 22 2006 at 05:34 PM said:
4. I'm a bit of a neat freak, when it come to electronics (probably because I don't really know what I'm doing) :) So using the single core wire allowed me to, very neatly, solder onto the pins, and extend onto the cable wire.
If you're such a neat freak, you must have really freaked when you melted the bottom of the connector with the soldering iron. The photos show before and after shots. :)

I was wondering how long it would take someone to notice that :( I got distracted as I was soldering... ;) This happens when you have a 5 year old!

lucoxade posted on Feb 23 2006 at 02:13 AM said:
Will any E810 connector do or does it have to be the one provided by axshop?

As long as it is an E810 serial cable and not a USB one it should be fine.
Some of the wire colours may change, but you should be able to determine the function of them. If you get a cable and can't figure it out, send me some pics and I'll try to help.

-(e)
 
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sweetlilmre

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lucoxade posted on Feb 23 2006 at 03:28 PM said:
I'm gonna try your guide but using one of these http://allgsm.co.uk/product_info.php?products_id=280

Wish me luck!

Can you open the shell casings on that connector? It looks sealed! (I hope not).
Not sure what the power connectors are for either.

Good Luck! As I said, give me a PM for help if you need it.
Also, if you don't come right, I will be in the U.K. from 04/03/06 to 15/03/06, if you can get to london, I could possibly bring a serial cable over for you?

-(e)
 
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OmarNawaz

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i think those power cables are wired to the ext port some require a voltage before you can write to them

that cable will make a good usb cable if you rewire it you can make a serial and usb host cable

those power leads could power the usb host

think i might buy me one
 

jokeman

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hi!

first of all, thanks to your research nubie and your documentation sweetlilmre

i bought a e810 cable like the one in the wiki, but inside it is very different... maybe the european version? there are more wires connected to the ext side and a more complicated circuit board on the PC side which is not labled

do you think, this cable will do it?

PC side back:
serial1.jpg


PC side front:
serial2.jpg


ext side back:
serial3.jpg


ext side front:
serial4.jpg


it isn't easy to see the wireconnections on the ext side so i'll write them down:

black: 12, 2, 19
green: 14
orange: 20
white: 22, 21
red: 24
blue: 13
brown: 3
violet: 17
yellow: 23
gray: 18

and another short question: is the serial cable only to get the console or can i use it to connect a standard serial mouse too?

thx for your help
 

sweetlilmre

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Hi,

jokeman posted on Mar 6 2006 at 12:07 PM said:
hi!

first of all, thanks to your research nubie and your documentation sweetlilmre


No worries :)

I'm in the U.K. at the moment, and don't have a cable with me to check the pin-outs (I really should have done a pin mapping in the wiki :( ). If you can wait until the 17th ish I can help you out. Perhaps someone else (Nubie?) can do so in the mean time?

You should at least be able to determine the 3.3V and ground pins, do you have a multi meter? If so try red and black and see if you get a +- 3V reading.

Where did you get this cable? I like that all the pins are soldered to the board, great for making a USB Host cable and other possibilities...


-(e)
 
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jokeman

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i have it from an austrian electric shop
the package says "Samsung PC link cable"
product number is PCB181NSE : SGH-E810
and outside the cable and connectors look the same like yours

the pinlayout of the ext side should be the same like on the other cable, shouldn't it? :huh:
nubie posted it here

2/12 Ground
13 TXD
14 RXD
20 CTS
22 VCC
24 DTR

so i can find out the pins on the pc-side (wirecolor)

but will it work? and could it cause any damage, if i try it?

i have a multi meter... should i connect the cable to the pc and then test on the ext side?

thanks :)
 
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sweetlilmre

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Hi,

jokeman posted on Mar 7 2006 at 11:07 AM said:
i have it from an austrian electric shop
the package says "Samsung PC link cable"
product number is PCB181NSE : SGH-E810
and outside the cable and connectors look the same like yours

the pinlayout of the ext side should be the same like on the other cable, shouldn't it? :huh:
nubie posted it here

2/12 Ground
13 TXD
14 RXD
20 CTS
22 VCC
24 DTR

so i can find out the pins on the pc-side (wirecolor)

but will it work? and could it cause any damage, if i try it?

i have a multi meter... should i connect the cable to the pc and then test on the ext side?

thanks :)

Ahh brilliant! Nubie is the man :). So if you check the VCC and ground pins (by plugging the pc side in and testing with a meter) and get 3.3V, that would be a start, you can then assume the TX and RX lines.

The only problem may be in getting TX / RX swapped (which won't cause any damage, just won't work).

SO:

black: -> Ground (linked by green link wire, other links)
green (or cyanish): -> RXD
white: -> VCC
light-blue: -> TXD

Basically you should desolder all wires, then just resolder the above to the relevant pins as per the wiki. Make sure no link wires are left soldered on the board, and make sure any non used wires are clipped or insulated.

What I really like about this cable is that you have enough wires for USB and possibly JTAG or TVOUT as well. Does the shop you got it from have a web site?


-(e)
 
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jokeman

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well...
i tested ground with the other pins and only get 0.3V - 0.4V

next, i'll desolder the pins and only connect the relevant ones...
to be shure: any possibility, that i could destroy the 2x if the CB will do any strange things?
 

nubie

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jokeman posted on Mar 14 2006 at 11:16 AM said:
well...
i tested ground with the other pins and only get 0.3V - 0.4V

next, i'll desolder the pins and only connect the relevant ones...
to be shure: any possibility, that i could destroy the 2x if the CB will do any strange things?

In my cable the Chip in the PC side NEEDS juice (~3.3v) from the GP2X to power it and possibly to set the line level.

I would recommend that you need to supply power the the chip in the PC side before you test the TxD and RxD for power, use an external battery pack or the GP2X.

I first connected only the power and ground to my GP2X, then when I used hyperterm to activate the serial port, I got 3v (GP2X output voltage) on a DC meter setting, and 6v AC on the multimeter (how serial lines communicate).

It certaintly seems like your cable is really different, I would try looking for a known pinout,

either start from the e810 side and get a pinout,

or start with the chip, it seems to be labeled, unlike mine.

Yikes!

Maybe a better idea would be for somebody to buy Axshop.com cables and distribute them to those outside the US.

Of course the actual GP2X side connector you got seems a million times nicer than the one I got, it has all the solder pads, so you could start over on the PC side and make a Printed Circuit Board (or use project board) and put a MAX232 chip on it if you don't work out the pins on this board.

Where did you get that one anyway? I wish we had a good source of these kind, perfect for breakout boxes.

EDIT:I just noticed your comment about destroying the GP2X.

Short answer Yes,
Long answer, Don't create a high current between the power and the ground pins.

One way to create a high current is to just connect them together, or connect them to wires with very low resistance (ohms).

The TxD and Rxd pins on the GP should be fairly resilient, They are after all made to watch for 3v to -3v, so grounding or powering them shouldn't be a problem, as long as they don't see the 12v/ -12v from the PC serial connector.

Check for high resistance with a multimeter if you are unsure before connecting the GP2X.

I would recommend using a battery pack to supply voltage, it will just explode if you connect its pins together, or use a 1 amp fuse as protection for the battery pack.

Then once you have sussed out the pins and got the TxD and RxD sending the correct voltages, go ahead and connect them to the EXT PCB.
 
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