Arduino Forum

Forum 2005-2010 (read only) => Hardware => Bugs & Suggestions => Topic started by: Manawyrm on Dec 20, 2009, 01:51 pm

Title: Make your Arduino USB for only 1 dollar!
Post by: Manawyrm on Dec 20, 2009, 01:51 pm
Hello, Arduino Community.
First sorry for my bad english...

I found a way to add an USB port to any 5 volt arduino:

You have to buy a Nokia DKU-5 datacable USB, you can find it on e*ay for only 1 dollar or euro.

It has to be this one:
(http://img97.imageshack.us/img97/9490/bgbgpg2kkgrhgohdiejlllv.jpg)

You only have to cut the PopPort on the Cable and Connect 5v gnd rx tx to your arduino.

Greets tobi31061

EDIT:
Here are the working drivers for the TI Chip:
http://segaemu.bplaced.net/DISK1.rar
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: bill2009 on Dec 20, 2009, 04:54 pm
Nice find. Thank you.
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: Manawyrm on Dec 20, 2009, 07:27 pm
NP. And i also found a cheap way to connect my calculator to my pc with this cable. ;D
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: westfw on Dec 22, 2009, 02:28 am
Also works with CA-42 type cables (about the same price.  Less than $3 shipped.)  There is a nice tutorial here:
http://www.uchobby.com/index.php/2009/10/04/diy-usb-to-serial-cable-for-3/

The CA-42 seems to be based on the Prolific USB/Serial chip rather than the TI, and the prolific seems to have a larger userbase and be supported on more platforms.  (I've yet to find Mac support for either the DKU-5 or other devices containing a TI USB/Serial chip.  Sigh.)
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: borref on Dec 22, 2009, 08:56 am
Quote
I found a way to add an USB port to any 5 volt arduino:

There appears to be a confusing mix of 5V/3V3 versions of these cables (or at least Google suggests this is the case). How did you wire it for 5V Arduino's (pin number/color on DKU-5 connector)?

I've converted a couple CA-42 type cables and they work ok for Rx/Tx and 5V USB bus power (no DTR/RTS for auto-reset however) . This required prying open the USB connector and soldering a wire directlly onto an SMD pin which is tricky. Perhaps your find is eaiser to convert. The prolific chip used in the CA-42 was indeed a 5V tolerant chip and I wonder if this is so for the DKU-5 as well.
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: 1315matthew on Dec 22, 2009, 06:45 pm
Hello everyone

I'm just posting this one message so I'll be allowed to post links and images.

Matt
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: 1315matthew on Dec 22, 2009, 06:46 pm
After reading this thread I picked up a DKU-5 cable from

http://cgi.ebay.co.uk/DKU-5-USB-DATA-CABLE-For-NOKIA-7250-3220-6100-6610-6820_W0QQitemZ230411003139QQcmdZViewItemQQptZUK_MobilePhones_MobilePhoneAccesories_MobilePhoneDataCables_JN?hash=item35a590e503

It has a prolific PL-2303 and a 3 core wire.

orange = GND
blue = RX
red = TX

I've tested it with my 5 volt board and it works fine.

(http://mattp.homelinux.com/images/other/IMG_8516)

(http://mattp.homelinux.com/images/other/IMG_8531)

Matt
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: Manawyrm on Dec 23, 2009, 10:17 am
Very nice to hear that this worked for you, but btw, my multimeter is broken i have problems with checking out the lines....

do somebody now the pins?
it has
brown orange green yellow red
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: n00b on Jan 20, 2010, 09:03 am
Quote
After reading this thread I picked up a DKU-5 cable from

http://cgi.ebay.co.uk/DKU-5-USB-DATA-CABLE-For-NOKIA-7250-3220-6100-6610-6820_W0...

It has a prolific PL-2303 and a 3 core wire.

orange = GND
blue = RX
red = TX

I've tested it with my 5 volt board and it works fine.


Ordered my one from the same place, came in the same box, but has 5 core wire.

Black: GND
Blue:    TX
White:  RX
Green:  VCC

Ps what order should theses be soldered to a 6 pin header?

Im guessing

1: GND
2:
3: VCC
4: TX
5: RX
6:
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: borref on Jan 20, 2010, 10:25 am
The "modified" FTDI cable (as used by SparkFun and others) is wired as follows:

1: GND - GND
2:
3: VCC - VCC
4: Pin 2 on MCU (AtMega RXD)
5: Pin 3 on MCU (AtMega TXD)
6: DTR to RESET on MCU

1 is referred to as the "black wire" and 6 as the "green wire" in some references (e.g. on Pro Mini boards).
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: n00b on Jan 20, 2010, 11:01 am
Quote
DTR to RESET on MCU


so..........

A: How do you determine what wire is the RESET on a DKU-5?
B: What are the ramifications of using the 3 core cable with just VCC/TX/RX?
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: borref on Jan 20, 2010, 01:48 pm
A: How do you determine what wire is the RESET on a DKU-5?
You trace the wire back to the chip and check against the chip's datasheet (or Google for relevant sources). There apperars to be as many variations on this cable however as there are suppliers.

B: What are the ramifications of using the 3 core cable with just VCC/TX/RX?  
I doubt you will ever find such a cable. The 3 wire GND/RX/TX however will enable Arduino to USB serial communication, but without auto-reset or power from USB.
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: westfw on Jan 20, 2010, 05:36 pm
Quote
B: What are the ramifications of using the 3 core cable with just VCC/TX/RX?  
I doubt you will ever find such a cable. The 3 wire GND/RX/TX however will enable Arduino to USB serial communication, but without auto-reset or power from USB.

For people who are too new to remember, no auto-reset means that when attempting to upload a sketch to the arduino, you have to manually push the "RESET" button at nearly the same time you hit the "upload" button.  It's not a big deal...

All of the CA-42 cables I've seen seem to be of the 3-wire variety.
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: n00b on Jan 20, 2010, 08:26 pm
Done a little research on the pin out of the Nokia Pop-port, so if anyone is lucky enough to get the 5 wire DKU-5 (like me :) ), grab your multimeter, strip the wires to the DKU-5 header, and use the diode setting to find out what colour wire correspond to what header pin.

(http://i55.photobucket.com/albums/g146/icecreamterror/dku-5.gif)

(http://i55.photobucket.com/albums/g146/icecreamterror/Picture-2-1.gif)

Title: Re: Make your Arduino USB for only 1 dollar!
Post by: Tchnclfl on Jan 24, 2010, 12:57 am
There's a nice tutorial out there somewhere for the same thing :P.

Quote
I doubt you will ever find such a cable. The 3 wire GND/RX/TX however will enable Arduino to USB serial communication, but without auto-reset or power from USB.


I just did the same thing with a CA-42 cable (very similar to DKU-5), and there were only those three wires.  I had to run a third down the length of the cable for +5V Vcc, but it works great now :).
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: yardleydobon on Feb 28, 2010, 12:27 am
@ noob
I find your post confusing. You say you got a 5 wire DKU-5 but then show six lines. Does your cable have VCC, GND, RxD, TxD, DTR (auto-reset) all at the connector with no extra work? If so that's amazing. Usually you have to work a little to get VCC and a lot to get DTR.

@ everybody who has used DKU-5
I was lead to believe by Tim Small's article that the DKU-5 transceiver had to draw power from the phone at 3.3V. Are those you using the DKU-5 having to supply 3.3V to it? Having to supply 3.3V to the cable would complicate things when working with 5V Arduino.
http://buffalo.nas-central.org/index.php/Use_a_Nokia_Serial_Cable_on_an_ARM9_Linkstation

I wrote an article on modifying a CA-42 to have VCC, GND, RxD, TxD, DTR (auto-reset). It was first on uChobby. Now it's on my blog and linked to by Hack A Day. Please leave a positive comment if you find this useful.
http://hackaday.com/2010/02/25/nokia-usb-cable-is-usb-to-serial-in-disguise/#comments

Title: Re: Make your Arduino USB for only 1 dollar!
Post by: westfw on Feb 28, 2010, 08:51 am
(I think your CA-42 post that appeared on uChobby was the first I had heard of this source of cheap USB/Serial converters (I think I had known that they WERE such, but had never noticed that they were cheap via the mass-market, or that they used standard-enough chipsets to be useful without special phone software.)   *I* found it useful, and have since bought about half-a-dozen such cables, aimed at all sorts of serial things that I'd like to talk to with USB-equipped computers.   (Don't be dismayed by the negative comments on hack-a-day; they seem to be mostly complaining about the long lag between your original posting and HaD picking it up, rather than the idea in general.))
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: yardleydobon on Mar 01, 2010, 01:55 am
Thank you for your kind comment. I first learned about using an old cell phone cable as a USB to Serial TTL cable about two years ago. I must say that I didn't come up with this idea and its an idea that is much older than my tutorial. However, I would like to say while this information was well known to a certain type of hacker it certainly wasn't well known to the Arduino community or other more casual electronics hobbyists. I feel this is true because I searched the Web high and low for an FTDI alternative for at least a couple nights before I came across a post that gave me a lead on using the CA-42.

The reason I wrote the article was not to dredge up some old hack and try to take credit for it but to popularize it and make getting into Arduino much cheaper thus making it more accessible to a wider group of people. That's the spirit of Arduino and open hardware after all.
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: Tchnclfl on Mar 01, 2010, 05:37 am
I agree that it is very useful, and also agree that you shouldn't listen to the negative comments on Hackaday.

I used your tutorial to create my USB-Serial cable, and I couldn't have done it otherwise.  Your guide was very thorough and descriptive, while others were incomplete.

:)
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: yardleydobon on Mar 01, 2010, 10:47 pm
That's very nice of you to say. Thank you.

@ everybody that finds my article useful
Please tell others. Also if you find an error in the article or have a unique experience with hacking your cable please post a comment on my blog.
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: radames on Mar 23, 2010, 04:12 am
hi there!
I'm really anxious about try this idea! Here is very hard to find ftdi chips and also they cost a lot, another problem is soldering smd and find a breakout, so you'll spend a lot to build your own ftdi conververt.
but one question, has anyone tried this cable on Linux? is there any driver?  I'll try it as soon as possible!
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: westfw on Mar 23, 2010, 06:22 am
Quote
has anyone tried this cable on Linux? is there any driver?

The "Prolific" chipset used on the CA-42 is one of the most popular USB/Serial converters in the consumer space, and it's well supported by most operating systems (it even worked fine on my Mac.)  But I've had troubles with the DKU-5 that some other people have mentioned.  Some of those seem to have the TI chipset, and it is NOT well supported except by windows :-(
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: anachrocomputer on Mar 23, 2010, 11:29 am
I've done this with a CA-42 cable that I got from Deal Extreme:

http://www.dealextreme.com/details.dx/sku.446

It worked fine with Linux, MacOS X and Windows (Windows needed a driver installed). It shows up as a USB serial port in Linux, as expected. I used a TO-92 size 3.3V regulator to supply power to the CA-42 from a 5V AVR development board.
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: Mike-K8LH on Mar 26, 2010, 12:41 am
Quote
I used a TO-92 size 3.3V regulator to supply power to the CA-42 from a 5V AVR development board.

Huh?  You have to supply the CA-42 cable with 3.3 volts?
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: anachrocomputer on Mar 26, 2010, 03:51 pm
Quote
You have to supply the CA-42 cable with 3.3 volts?


Yes, according to those web pages that document the method, and the Prolific chip's data sheet. It's surprising, but the Prolific chip is not powered from the USB port, but from the phone (in the original setup).
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: Mike-K8LH on Mar 26, 2010, 05:45 pm
Which web pages, please?  All of the CA-42 pages I've looked at suggest the Prolific chip is powered from USB port.  I only came across a couple pages that said otherwise but they were describing the DKU-5 cable.  For example, here's an excerpt from this page; http://buffalo.nas-central.org/index.php/Use_a_Nokia_Serial_Cable_on_an_ARM9_Linkstation.

Quote
pin 4 (sticks out a bit further)+3.3v this is used to power the transceiver on the DKU-5 cable I have (red), but not the CA-42


Title: Re: Make your Arduino USB for only 1 dollar!
Post by: Mike-K8LH on Mar 26, 2010, 07:09 pm
Hey Guys,

May I ask if the CA-42 cable starts up ok with nothing connected at the Phone end of the cable?  

I just received my CA-42 yesterday ($2.68 from China) and installed the PL-2303 drivers from the Prolific web site on an XP-Pro SP3 laptop and on a Vista Home laptop but after the device drivers are matched up and installed after plugging in the CA-42 both laptops report the same "Unable to start (Code 10)" error.  I'm thinking I have a defective cable.
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: westfw on Mar 27, 2010, 01:56 am
Quote
May I ask if the CA-42 cable starts up ok with nothing connected at the Phone end of the cable?  

I have two varieties, and they both show up with nothing connected on the phone end.
One is from ebay seller "topvshonw" and the other from ebay seller "mehonblue"
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: Mike-K8LH on Mar 27, 2010, 12:35 pm
Thank you Sir.  I'm going to assume I've got a bad cable.  It'll be interesting to see if Chinese seller will replace this $2.68 item.
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: Mike-K8LH on Apr 13, 2010, 07:49 pm
I just received a replacement CA-42 cable from the Chinese vendor today but I have the same "Cannot Start (Code 10)" error on the XP-SP3 laptop (PL-2303 driver 2.0.13.130) and on the Vista laptop (PL-2303 driver 3.3.10.140).

Is it possible I'm using the wrong drivers or could I have another problem?

Thanks in advance guys.   Mike McLaren, K8LH
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: Mike-K8LH on Apr 14, 2010, 04:07 am
It's workin'...  Hoo-rah!!!  

I ended up using an older driver (PL-2303 v2.0.2.5 for XP) from here;

http://www.usglobalsat.com/download/546/win_drivers.zip
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: cjparish on Apr 15, 2010, 02:45 pm
I have just bought a DKU 5 cable, but I have had no luck using it with my mac.
When I plug it in hardware growler spots it and reports it as a USB-UART controller and system profiler shows this:

 Product ID:      0x0232
 Vendor ID:      0x6547
 Version:       0.01
 Speed:      Up to 12 Mb/sec
 Manufacturer:      ArkMicroChips
 Location ID:      0xfa230000
 Current Available (mA):      500
 Current Required (mA):      500

However I am unable to locate the serial port in /dev anywhere and the arduino IDE cannot find it either.

Do I need a specific driver?
Is there a file I need to edit?
Does it involve the sacrifice of a chicken?

Help!
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: anachrocomputer on Apr 16, 2010, 12:25 pm
Quote
Do I need a specific driver?


Yes, I think you do.  The manufacturer's name, ArkMicroChips, should be a clue.  The normal Arduino USB-to-serial chip is made by FDTI. My CA-42 cable uses a chip made by Prolific Technology. Both these chips have drivers built-in on Linux (which OS are you using, BTW?), but the Ark chip probably does not.
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: cjparish on Apr 16, 2010, 03:03 pm
Quote
The manufacturer's name, ArkMicroChips, should be a clue.


Well gee, I never would have thought of that on my own!  ;D
I have already searched for a Mac driver from ArkMicroChips and I haven't had any luck. I was hoping that someone might know where I could get one, or might know that I was doing somthing wrong.

I am running OSX 10.6.3

Oh well, if it doesn't work at least it only cost me £3 on eBay and now I have some nice 3 core cable!

Thanks for your continuing help and support folks. This community is very good. :)

Chris
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: pluggy on Apr 16, 2010, 04:40 pm
Got my cheap CA-42 cable from a Hong Kong vendor today. Just to be different it has 4 wires, wired to Gnd, TX,RX and USB VBus.  Ignoring the Vbus and powering the Arduino (home brew with 5v 328 chip) seperately it works fine on Ubuntu pressing the reset at the opportune time.  Its detected as a PL2303 and installs as a standard ttyUSBx port.  It took a long time to come but the UK ebay page is:  

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=280450361448&ssPageName=STRK:MEWNX:IT
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: pluggy on Apr 16, 2010, 06:28 pm
Flushed with success, I dug out another one I failed with a while back, again a CA-42, externally looks almost identical, but had 3 core cable and didn't work, It received with lots of errors but wouldn't upload.  Ubuntu reports and loads the device fine (identically to the working one), I guess its a bad one, the downside of paying next to nothing on Ebay..........
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: anachrocomputer on Apr 19, 2010, 12:32 pm
Quote
I have already searched for a Mac driver from ArkMicroChips and I haven't had any luck.


Ah, you didn't say that in your original message! I think the only way forward is to find that driver, somehow.
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: cjparish on Apr 19, 2010, 01:11 pm
Quote
Ah, you didn't say that in your original message!


Sorry, that was my fault there. i hace found a driver for Linux, but as yet none for Mac and I am fairly sure that Linux drivers don't work on the Mac. Rats.

Looks like I wasted £3. :(
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: raron on May 17, 2010, 06:56 pm
Great tip! I finally have an alternate way of uploading sketches :)

Quote
After reading this thread I picked up a DKU-5 cable from

http://cgi.ebay.co.uk/DKU-5-USB-DATA-CABLE-For-NOKIA-7250-3220-6100-6610-6820_W0...

It has a prolific PL-2303 and a 3 core wire.

orange = GND
blue = RX
red = TX

I've tested it with my 5 volt board and it works fine.



I too got a DKU-5 with 3 wires. But I had the TX/RX colors the other way around. Even though I measured the pinouts beforehand, I managed to confirm Murphy's law and switch them. Thankfully, the DKU-5 held (might be because I had a 220 ohm on the TX from an arduino, just in case).

This guy have a really nice writeup on the nokia serial converter: http://www.uchobby.com/index.php/2009/10/04/diy-usb-to-serial-cable-for-3/#more-492

EDIT: Forgot to say, I found a tip in the link above helpful: The one about finding X and waiting X seconds after clicking upload, since there is no auto-reset. For me X was 2 seconds (give or take). Only tried twice so far, and I don't remember which bootloader I have on my breadboard arduino thing. Probably ADABOOT (http://www.wulfden.org/TheShoppe/freeduino/ADABOOT.shtml).
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: doshdance on Jul 22, 2010, 11:29 am
sorry... just to feed my curiosity..
this can be used in the arduino 0018?
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: pluggy on Jul 23, 2010, 11:11 pm
Quote
sorry... just to feed my curiosity..
this can be used in the arduino 0018?


If it works at all, it will work with any Arduino IDE.  If you care to read the whole thread, you'll find a lot of pitfalls, a FDTI breakout board whilst more expensive, is a lot less grief.........
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: doshdance on Jul 24, 2010, 06:29 pm
guys... i am a new comer here in the Arduino family.. although i am only exposed to PIC earlier.just started to play with Arduino about 3 days ago.

yup... already tested with the pl2303 or Arduino 0018. my Arduino board hasn't arrive yet.. so i have to bare with building up from the the source, 328s and the pl2303 (although i already bought the FTDI breakout board)
its not cheap for a jobless guy like me.(just finished studying)

its proven success to use the pl2303 as replacement for ftdi... thanx guys
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: aadeesh on Aug 03, 2010, 06:48 pm
Hello guys.. I hooked my DKU-5 cable (Third Party) after seeing this post...
The cable got 5-wires and i measured the voltages & they came out to be-

Green - GND
Yellow - VCC (3.23V)
White - 0.11V
Black - 0.14,0.15,0.16V (the reading fluctuated)
Red - 0.12 0.13V

Now which is Tx and Rx ? :-?
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: doshdance on Aug 06, 2010, 04:16 am
Aadeesh....

I'm sorry, i didn't do the voltage test.. he he he..
why dont u try breaking the case....
my dku-5 even got labels... the same as for all there is on ftdi's...
dtr cts r1 and a lot more...
rx tx...

i waited for a month to get the guts to break it.. what a relief!

Title: Re: Make your Arduino USB for only 1 dollar!
Post by: ichilton on Aug 12, 2010, 02:04 pm
Hi,

Will the RX pin on the PL2303 be ok with 5v straight from a 5v Arduino TX pin?

The guide at uchobby.com uses a divider but others seem to connect the RX straight to the Arduino TX.

Thanks,

Ian
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: mpeuser on Aug 13, 2010, 01:48 am
Connecting 3V and 5V devices is not such a secret. It is not an issue of voltage but of current. You have to avoid the flow of much more than - say - 100 uA through the protection diodes in the input circuits. To my experience even 1mA will generally not destroy them.

For the voltage of around 1V between 5V and 3V3V + 0V6 a serial resistor of 10k would be more than sufficient protection; I think 1k will also do the job...
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: ichilton on Aug 13, 2010, 10:08 am
Hi,

Is it good practise to put a 10k inline on both the RX and TX?

Thanks,

Ian
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: mpeuser on Aug 14, 2010, 01:29 am
This has nothing to to do with good practice but with voltage and current :-) The line transmitting @ 3V3 to a 5V device does not need any resistor, but it will do no harm.
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: doshdance on Aug 15, 2010, 11:05 am
that depends... but i doubt the arduino will send more than 5 volts to the RX of the PL2303 as what i tested with my multimeter.. they only sent about 4.73v or something...

just test the pins of the arduino.. if u get more than 5v... then u might need to drop it with a ladder. but as far as i know... i  connected it straight from the arduino's TX.
hope this helps...
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: mpeuser on Aug 15, 2010, 11:46 am
Its not a matter of voltage but of current.. nevertheless do what you want  ;D
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: ichilton on Aug 18, 2010, 11:12 am
Hi,

I have bought 2 cables, a CA-42 and a DKU-5.

Both arrived and have the PL-2303 chip and when stripped down, both look exactly like this board (and one has the exact same markings):
http://kwartzlab.ca/blog/dw/2010-04-23/reverse-engineering-cheap-ardu

However, for some reason my RXD pin is Pin 4 instead of the 9 in the article which is strange!

Once i'd sorted that though, I can get 5v between GND (6) and VCC (2) and I can connect RXD (4) to TXD (12) and successfully echo characters across in Hyperterm and Realterm.

However, I want to also use DTR so Arduino will auto-reset on program but i'm having trouble finding the DTR pin. I have set DTR and RTS using the toggles in Realterm but going through all the pins with a multimeter between GND (6) and the other pins, none seems to give anything.

Any ideas how I can find DTR (and RTS) and why i'm not seeing it?

The other thing I dont quite understand is why on the above link he uses pin 10, which he had identified as RTS and uses it & calls it DTR in his final pin-out....any ideas why he did that?

Thanks,

Ian
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: anachrocomputer on Aug 18, 2010, 12:48 pm
Thanks for posting that detailed tear-down of the USB/serial cable!  I have two like that one, and the information will be very useful.  So far, I've cut the end off one cable, but the other is intact -- not for long!
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: borref on Aug 18, 2010, 08:29 pm
Quote
Any ideas how I can find DTR (and RTS) and why i'm not seeing it?

The cables I've converted don't look quite like yours.

The trick to finding DTR/RTS however is to look at the datasheet for the specific Prolific chip used and then check to see if the DTR pin is brought out to some nearby pad. On mine it was not, so the only option left was to solder a tiny wire from the chip pin itself.
Title: Re: Make your Arduino USB for only 1 dollar!
Post by: ichilton on Aug 18, 2010, 11:46 pm
Hi,

Quote
The trick to finding DTR/RTS however is to look at the datasheet for the specific Prolific chip used and then check to see if the DTR pin is brought out to some nearby pad. On mine it was not, so the only option left was to solder a tiny wire from the chip pin itself.

The problem is you can't see the chip as it's covered with one of those black blobs - so all you have is the pads on the pcb :(

Ian