interfaceing to a PC

Forum 2005-2010 (read only) Hardware Interfacing
1

I am connecting a Arduino Pro Mini (5 volt version) to a PC serial port. I assume I will need a interface to bring the TX/RX levels from the Arduino up to the PC standard serial port.

what are your suggestions.

Thanks

2

Maxim makes a number of chips to do the %v (or TTL) serial to RS-232 level shifting function. The oldest one is the MAX232 chip, but there are many other, newer ones:

3

Hay thanks, I read someplace else that it needs to be inverting, is that correct?

4

I would recommend going with one of the compatible TI MAX232 chips, rather than an actual Maxim part. The TI chips tend to be a lot cheaper, under a dollar as opposed to 3, 4, or even 5 dollars for a Maxim-produced chip. Here: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=296-6940-5-ND

5

For my breadboard Arduino clone (Duinostamp from Fundemental Logic) I bought this USB serial breakout module from Sparkfun. It works great, has blinky lights, can power your pro mini if you wish. Lots of extra features that the FT232RL chip and driver supports. No invertor needed and it uses the cool mini-B usb connector.

I've wired a .1mfd cap between the modules DTR pin and the clone's reset pin so the Arduino IDE auto-reset function works fine. All in all it's the nicest USB serial module I've come across for breadboarding.

Lefty

6

I already have the ST232AB in stock, will it work? It seems to match the MAX232 close.

7

I read someplace else that it needs to be inverting, is that correct?

Yes, all these TTL-to-RS232 chips are inverting. You have to look closely at the data sheet, but it's definitely the usual way.

I already have the ST232AB in stock, will it work?

And yes, the ST232 will work. It seems to be an ST clone of the MAX232.

8

Awsome, thanks everyone for the info, Just a little modification to my board that uses the ST232 and I'm in!!

Thanks