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Topic: Tutorial for hacking a CP2102 USB from ebay and uploading a sketch to an Atmega (Read 18877 times) previous topic - next topic


xl97

what are you looking for? standalone boards?

but in DIP style?

maybe Anatools.com will help, and his Anarduino kit:

http://www.anatools.com/anarduino/

http://www.anatools.com/anarduino/inst.jsp

I found him great to deal with and very nice.

I used a few of these...they are great and are assembled in like 5 minutes.

CrossRoads

@msev - yes.
Also DIP ATMega1284's. Extra IO (32 total), dual hardware serial port.

You can see some of my designs at the link in my signature. Gotta find my FTP password so I can upload some more pic's.

Or here for a minimal component '328:
http://store.nkcelectronics.com/arduino-runtime-board-rev-b.html
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

msev

I'm looking for a design with the dip package that would ideally have such a pinout for programming pins that it would be directly plug-in friendly for the modified cp2102. Probably I'll have to modify some .brd file of an exsisting  minimal arduino project.. It would be nice if there was a topic, a collection of all minimal arduino projects together :D

Brad Burleson


When the arduino has an onboard cap in series from DTR pin to the chip's reset, then a cap is not needed on the CP2102 module.


Thanks for that - I'd been wondering why I'd seen the 0.1uF cap added to the board that RandallR pictured thinking that it shouldn't be needed if the 'arduino' has it's own 0.1uF cap on the reset line.

I guess the idea was to avoid having an extra cap on each clone you build?  Too late for me, I always do that.

I'm posting just to confirm for the OP that I bought a pair of the same boards (or at least appear to be the same) that RandallR pictured from dealextreme and the "fix" was as simple as cutting the trace that goes to the RST pin and running a small wire from DTR.  No 0.1uF cap needed if your target board already has it.

I also had to swap the TX/RX lines between the CP2102 and the target board (I've seen some boards where this wasn't needed).

Hope this helps,

Brad.

msev

Did you swap them because of the pinout on your arduino, or because the board was mislabeled (that rx was labelled as tx?)?

Brad Burleson


Did you swap them because of the pinout on your arduino, or because the board was mislabeled (that rx was labelled as tx?)?


My Arduino board uses the standard FTDI pinout if that helps (I only bought the CP2102's to test).  I believe this board actually has RX/TX marked correctly since with my other TTL/USB adapter also crosses TX/RX.

FWIW,

Brad.

xl97

its common form what I have seen..

some mark it as to what it GOES to.. an some mark it as what it IS..

once of the first things I try to swap when an FTDI sketch upload fails..

what/where are these boards you are getting??  (that has the DTR pin broke out)

my cheapie cables only ave 4 lines (5 if you count the 3.3v pad)  5v+, GND, RX, TX..

I hve to manually hit the reset button to upload sketches.. not a problem.. but going forward.. some projects wont have a reset button at all.


retrolefty

Quote
what/where are these boards you are getting??  (that has the DTR pin broke out)


Here are the ones I bought, can't beat the price: 
http://www.ebay.com/itm/370532286388?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

Lefty

xl97

you dont have to use the 6-pin header do you?

I mean treat this like any other FTDI cable..yes?

as long as I run 5v+, GND, RX, TX to my chip.. Im good.. I can then use/tap the DTR pad from the bottom of the board to use on the DTR of the circuit Im uploading my sketch to....right?

a shame it was brought out on top like the other pins.

also is there a driver for it?


thanks


CrossRoads

Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

Brad Burleson


you dont have to use the 6-pin header do you?


Nope. You can wire it up any way you choose.  I do use 6pin headers simply to keep with the standard FTDI pinout.

Note the included (very short) cable actually only has 5pins (you can see that in the picture that Lefty posted).

Quote

I mean treat this like any other FTDI cable..yes?


Sure, just get a couple of the 6pin female crimp housings (such as http://www.pololu.com/catalog/product/1905), remove the single pin plastic housing on each pin, and insert the pins in the correct order.  Or use whatever size header you want, as long as it matches your board.

I'd suggest testing the pinout first just in case :-)

Quote

as long as I run 5v+, GND, RX, TX to my chip.. Im good.. I can then use/tap the DTR pad from the bottom of the board to use on the DTR of the circuit Im uploading my sketch to....right?


You don't really need to pass 5v, but you've got the idea.  I was going to post a picture of a modified board but there isn't much to show - simply a cut trace and a jumper wire.  Takes 2 minutes and seems to work great.

Quote

also is there a driver for it?


Yup.  I think there is a link earlier in this thread.  If not, you can find the driver here http://www.kerrywong.com/2010/07/16/an-arduino-compatible-using-cp2102/

Hope this helps,

Brad.

xl97

thanks for the reply..

even found it a buck cheaper on ebay too:

http://www.ebay.com/itm/130683943875?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649


thanks!

msev


@msev,
a board like you describe is easy to make.


Are you willing to design it for me since you have a lot of experience (in Eagle)? With Dip atmega328.

CrossRoads

Sure - which parts do you want to keep, and how do want the connector?
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

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