USB to serial

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I have just built a Serial programmer based on the specifications on lanos.com (PonyProg), and it is working. The only problem is that my laptop does not have a serial port to connect it to.

Can you suggest some cost-effective way to get a serial port (i have seen cables only above 20$), or how to make an USB programmer?

If making the USB programmer would include some AVR programming I can do this, because I have a desktop PC on hand, but I want to use my laptop for development, because the desktop is not mine.

Thanks,
axos88

axos88

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Well serial-to-usb converters arn't that expensive to buy... but if you prefer to make one of your own, you should take a look at the FT232 from ftdichip. I've used them and they are very easy to use. drivers are provided on the ftdi webpage.

and you need a level converter for the rs232 side. and volla, 2 IC's and you've got your serial->USB converter. ( with NO programming required )

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I made the AVRUSB500 programmer:

http://tuxgraphics.org/electronics/200510/article05101.shtml

And am quite happy with it. I removed most of the extra parts as I used an FT232RL which has much of the extra passive stuff integrated already and I also removed the bitbang self-programming part of things, as I already had another programmer to do it with. Ended up being quite a small programmer at just over 1" square, as I did my own PCB and used a mini-usb connector.

Works like a charm and is compatible with AVR studio, avrdude, etc.

As for the USB-Serial converter cable, you can find the odd cheap one such as:
http://www.amazon.com/USB-Serial-RS-232-Adapter-Cable/dp/B000BI95W0
but I'm not sure if there's any problems using them for cheap bitbang programmers, as I'm not sure the pins can individually be changed. Someone else would have to verify that.

Clancy _________________ Step 1: RTFM Step 2: RTFF (Forums) Step 3: RTFG (Google) Step 4: Post

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clpalmer wrote:
As for the USB-Serial converter cable, you can find the odd cheap one such as:
http://www.amazon.com/USB-Serial-RS-232-Adapter-Cable/dp/B000BI95W0
but I'm not sure if there's any problems using them for cheap bitbang programmers, as I'm not sure the pins can individually be changed. Someone else would have to verify that.

It appears that this one uses the Prolific chipset. If you read the reviews you will see that well over 50% of the users had trouble getting it to work with their PC and other device. This is pretty typical for the PRolific chipset.

My advice is use the FT232R based converter and even then it may not ALWAYS work with everything. They do work for me, however.

-Tony

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I just bought a second Keyspan-brand USB-Serial converter. My initial Keyspan has worked great -- the Radio Shack brand did not. I don't know what chipset the Keyspan uses.

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Spamiam wrote:
It appears that this one uses the Prolific chipset. If you read the reviews you will see that well over 50% of the users had trouble getting it to work with their PC and other device. This is pretty typical for the PRolific chipset.

That was just as an example of the cheaper ones you can find sometimes. I've seen several different ones around for $5-$10 on sale.

Clancy _________________ Step 1: RTFM Step 2: RTFF (Forums) Step 3: RTFG (Google) Step 4: Post

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PonyProg uses the serial port in a modem signal bit-banged mode that is fast enough on a true serial port, but is very very slow and error prone using USB to Serial converters. You just might be able to download a small bootloader and then use that to load your programs, but I haven't read much to indicate that PonyProg with USB to Serial converters is a good idea. Anyway, the cost of a USB to Serial converter cable just about covers the cost of an AVRISP, so why wouldn't you go that route and skip all the hassle?

Smiley

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Good point, Smiley!

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Actually I have found a solution on a lowcost USB programmer, USBTinyISP. It needs a pre-programmed uC, but that's not a problem, because I have a serial programmer on hand, so I can just "borrow" a serial port on a computer, and do the pre-programming, and afterwards, hurray USB :)

Link: http://www.ladyada.net/make/usbtinyisp/index.html

axos88

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Glad that you have that worked out, axos88. I still like Smiley's advice for someone starting out without any programmers to consider the USB-enabled Dragon or AVRISP MkII. Atmel's devices tend to have frequent firmware upgrades to accomodate new devices over time.