Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: pomprocker on January 19, 2009, 03:09:42 AM

Title: USB to RS232 Converter Schematics in Eagle
Post by: pomprocker on January 19, 2009, 03:09:42 AM
I'm trying to make a circuit that will integrate a USB to RS232 converter. I am using cadsoft eagle.

The converter I am trying to mimic is sold by parallax:
http://www.parallax.com/Store/Accessories/CablesConverters/tabid/166/ProductID/378/List/0/Default.aspx?SortField=ProductName,ProductName

The level converter it uses is:
Zywyn ZT213LEEA

I have found the schematic in the FT232RL datasheet, and I would like to use the Zywyn, but unfortunately I can not find the part in eagle. The data sheet lists alternatives, but I am unfamiliar with this IC and not sure how they compare.

Shown on page 23 here:
http://www.sparkfun.com/datasheets/IC/FT232R_v104.pdf


Hope you can help me find a compatible level converter that actually has a part drawing in eagle.
Title: Re: USB to RS232 Converter Schematics in Eagle
Post by: Soeren on January 19, 2009, 05:07:01 AM
Hi,

Quote from: pomprocker on January 19, 2009, 03:09:42 AM
The converter I am trying to mimic is sold by parallax:
http://www.parallax.com/Store/Accessories/CablesConverters/tabid/166/ProductID/378/List/0/Default.aspx?SortField=ProductName,ProductName
Why???
It's only $15, so if you have to work on the project for much more than say, an hour, even the Because-I-CanTM factor starts to seem silly
And you have to pay for components and a box as well... Bad idea, waste of time and money without any redeeming sides.


Quote from: pomprocker on January 19, 2009, 03:09:42 AM
[...] unfortunately I can not find the part in eagle.
[...]
Hope you can help me find a compatible level converter that actually has a part drawing in eagle.
Well, copy a similar packet in the library editor and change what's different, then you have it.
Title: Re: USB to RS232 Converter Schematics in Eagle
Post by: pomprocker on January 19, 2009, 11:56:46 AM
Why?

like I said,
Quote
I'm trying to make a circuit that will integrate a USB to RS232 converter
meaning, its going to be part of a bigger circuit. Besides, I already own one of those parallax converters.

I found a couple tutorials on how to make my own eagle parts, just hoping i could avoid that for now.
Title: Re: USB to RS232 Converter Schematics in Eagle
Post by: Soeren on January 19, 2009, 04:57:57 PM
Hi,

Ah OK, but you could still hack an adapter, connect it in with enamelled copper wire and save time and cash.
Copying an Eagle part is a 10 minutes job really.
Title: Re: USB to RS232 Converter Schematics in Eagle
Post by: Webbot on January 19, 2009, 08:07:38 PM
Yeah - create your own Eagle package. May take 10 minutes but then you can re-use it across other projects
Title: Re: USB to RS232 Converter Schematics in Eagle
Post by: pomprocker on January 20, 2009, 11:21:31 AM
I figured out what to do.

Turns out I can use the MAX213CAI

Unfortunately, the only one in the Maxim eagle library was the MAX213ECWI, which is a 28-pin SO package, the CAI is an SSOP package otherwise the same.. So i simply just made a copy of the MAX213ECWI, renamed it, and changed the package and there I had it.



It was just brought to my attention, that instead of using two ICs in the circuit I am building to try to see if there is a single IC that does this?

Right now I was planning on using the ft232rl and the max213 to handle USB to RS232 logic levels
Title: Re: USB to RS232 Converter Schematics in Eagle
Post by: pomprocker on January 30, 2009, 05:20:13 PM
So i'm having trouble finding the MAX213CAI in stock anywhere!

Can anyone help me find an equivalent at a reasonable price!
Title: Re: USB to RS232 Converter Schematics in Eagle
Post by: Admin on February 07, 2009, 11:08:06 AM
No longer sold except for here:
http://www.newark.com/jsp/search/productdetail.jsp?SKU=67K4407&CMP=AFC-QO1721829242

You have to buy 46 of them to get it from Newark . . . for only $6 each ;D
Title: Re: USB to RS232 Converter Schematics in Eagle
Post by: pomprocker on February 07, 2009, 01:37:47 PM
Yeah the 213 series seems kind of hard to come by, whats the deal? Have they been replaced by something better? Why are they so much?
Title: Re: USB to RS232 Converter Schematics in Eagle
Post by: pomprocker on February 13, 2009, 03:44:19 PM
Is the MAX232 the successor of the MAX213?
Title: Re: USB to RS232 Converter Schematics in Eagle
Post by: Admin on February 15, 2009, 08:59:16 PM
FYI: https://www.silabs.com/ has a USB to rs232, USB to rs422, and USB to rs485 chips
Title: Re: USB to RS232 Converter Schematics in Eagle
Post by: pomprocker on February 15, 2009, 09:56:32 PM
Yes I have a CP2103 breakout already, but I kinda like the FT232RL a little bit better
Title: Re: USB to RS232 Converter Schematics in Eagle
Post by: Admin on February 15, 2009, 10:01:44 PM
Quote from: pomprocker on February 15, 2009, 09:56:32 PM
Yes I have a CP2103 breakout already, but I kinda like the FT232RL a little bit better
CP2103 and the FT232RL doesn't do rs232, just TTL.

silabs was claiming to have a USB to rs232 chip on their main page. I didn't search the site hard enough to get you a link though . . .
Title: Re: USB to RS232 Converter Schematics in Eagle
Post by: pomprocker on February 16, 2009, 12:12:19 AM
I looked a bit and couldnt find it. If you find it let me know
Title: Re: USB to RS232 Converter Schematics in Eagle
Post by: Admin on February 16, 2009, 06:48:17 AM
yea no luck finding it here either . . . for some reason the connection to silabs.com from thailand is painfully slow, so i kinda gave up before doing a thorough search . . .
Title: Re: USB to RS232 Converter Schematics in Eagle
Post by: Admin on February 17, 2009, 08:53:13 PM
You know, I think Silabs advertised RS232 when they really meant to say the newer EIA232 (which is TTL level signals).
Title: Re: USB to RS232 Converter Schematics in Eagle
Post by: MaltiK on February 20, 2009, 07:28:59 AM
http://www.surplusgizmos.com/Prolific-USB-to-Serial-TTL-Development-Module-wCable-Model-PL2303XA_p_1565.html

Schematics provided, I myself have mimicked it because they would not ship to me, and the chips were easily found on mouser and digikey, even some freebies from TI