Comments on: Really cheap USB to TTL on Atmega : 1.70$

By: admin

admin — Wed, 16 Jan 2013 13:07:38 +0000

Yes, just change the code if needed

By: Nemanja

Nemanja — Wed, 09 Jan 2013 17:51:30 +0000

is this cable compatibile with atmega328p?
salut
Nemanja

By: willmans

willmans — Fri, 17 Dec 2010 23:24:10 +0000

Newer PIC mcu:s have settings to invert the hardware USART, that is good because it can be used directly with the cheap USB-serial converters.

By: admin

admin — Sun, 24 Oct 2010 22:45:47 +0000

@Phillip : don’t forget to swap RX and TX from the AVR to RS232 converter:

AVR === RS232
RX < === TX
TX ===> RX

By: Phillip

Phillip — Sun, 24 Oct 2010 22:29:50 +0000

I’ve been playing with this for the last day, and I’m not having success. I found an identical looking cable, but the board inside is slightly different. Still, I identified the pins. I hooked RX and TX together, and using cutecom I am receiving exactly what I am sending each time, so I know the cable itself is working properly.

Using your code on the AVR, I’m sending “a\r\n”, and that’s it. However, using cutecom I only see things like x00 repeated over and over. Is there something else that I need to do on the software side in order to translate the messages, or am I just missing something huge?

This is the first time I’ve delved into serial comm before, so please be gentle.

By: Bob

Bob — Mon, 11 Oct 2010 02:01:33 +0000

bernt,

I was using a 7404 on mine and it worked well. There definitely aren’t any handshaking lines hooked up on these converters

By: admin

admin — Sun, 10 Oct 2010 21:23:52 +0000

@bernt, I missed this comment (don’t know how). Yes simple inverter will do the trick. I don’t have some here so, never tried this.

The other lines are standard db9 lines, so yes modem control ones.

@Bob, I cut the plastic w/ a knife, and cut the db9 pins before.

By: Bob

Bob — Sun, 10 Oct 2010 21:04:39 +0000

how did you pull the rs232-side housing apart? I destroyed one of these a few months back trying to cut the plastic off

By: bernt

bernt — Fri, 17 Sep 2010 04:28:19 +0000

What about using specialized inverter ICs?
(examples: 5-pin 74LVC1G14GW single inverter,
6-pin SN74LVC2G06DCKR double inverter)

If you are not worried about soldering SMD, its:
+ simple (1 only component is possible, no special software)
+ cheap (depending on how you buy, it might still be < 2USD, including the cable)
+ fast (short transition time + hardware UART)

Do you have any idea what the two (or more?) extra pins are for? …any modem control lines?

Have a nice day!

By: admin

admin — Thu, 16 Sep 2010 21:37:17 +0000

@Alex and @Gar, I haven’t found the time right now. But yes I NPN on the receive pin will provide a nice stuff. (inversion on the send isn’t a big deal) .

@Madge: I used Linux, so no driver is need, works out of the box. Just read/write to /dev/ttyUSB0.
For the ebay vendor, , don’t remember but every cheap (<2$) should work.

Bye