Need Help With "USB to RS-232" Connection

TECH GEEK

Ok so the problem I face is that I have two BASIC STAMPS 2 boards, however they both have a "RS-232 serial" connection & I only have access to 2 computers that can program the boards. Only one has a RS-232 port and that same computer is older than I am (it's 20+ years) and running on Windows 95. Plus it seams to have a problem with random crashes & it will only save to floppys. Anyways the other computer I have is a 2-month-old Windows 7 laptop, the oly problem is that it only has USB ports and a few other ports that are not usefull for this project.

What I need help with is as follows:

• A schematic for a USB to RS-232 adapter, that:
  • Will function properly with:
    • Board of Education Development Board - Serial Version (Rev C) with a BASIC Stamp 2 Module (Rev F)
    • BASIC Stamp 2 OEM Module
  • And is simple to make (no hard to find parts like: IC's, ect...)

---OR---

• A few links for some USB to RS-232 adapter cables.
  • THEY MUST BE UNDER $15.00 TOTAL (PRICE+TAX+SHIPPING to U.S.A. ZIP Code 18929)
  • THEY MUST WORK WITH BOTH BOARDS I HAVE (LINKS ABOVE IN PURPLE)
  • COMPATIBLE WITH Windows 7 (However Windows 7 does have "troobleshoot compatibilty" feature that seems to work well with older applications/programs)
  • I perfer stores that are very reliable (Amazon, eBay, ect.)

=THANK YOU=

=TECH GEEK=

Mike Green

Parallax makes a USB to RS232 adapter for $15 (here), but that doesn't include tax and shipping. It will work with both boards you have and is compatible with Windows 7. FTDI makes the chip that Parallax uses and they market their own adapter, but it costs more. You could make your own using the sample schematics from FTDI and Maxim (for the MAX232 chip for the logic to RS232 converter). I doubt you could make it as cheaply as Parallax and many USB to RS232 serial adapters will not work for programming a Stamp or a Propeller (or some other microcontrollers). You may end up buying a cheap adapter that won't work for you. Get the Parallax adapter or one from FTDI.

TECH GEEK

ok thanks
btw can u post links to all the stuff u mentioned

Mike Green

I don't have links to all the stuff I mentioned. Do a Google search for "ftdi ft232rl datasheet" and "maxim max232 datasheet". Usually near the back of the datasheet there will be reference design schematics. The Stamps and Propeller require transmit data (TX), receive data (RX), and dataset ready (DTR) signals to work. Others are optional.

TECH GEEK

Mike Green wrote: »

I don't have links to all the stuff I mentioned. Do a Google search for "ftdi ft232rl datasheet" and "maxim max232 datasheet". Usually near the back of the datasheet there will be reference design schematics. The Stamps and Propeller require transmit data (TX), receive data (RX), and dataset ready (DTR) signals to work. Others are optional.

I am having trouble finding anything related to computer ports, cables, adapters, computers, ect... that says "dataset ready"
When u said "dataset ready (DTR)"... did u mean, "Data Terminal Ready (DTR)" ???? <-- this is also a link to wiki artical

hover1

TECH GEEK wrote: »

I am having trouble finding anything related to computer ports, cables, adapters, computers, ect... that says "dataset ready"
When u said "dataset ready (DTR)"... did u mean, "Data Terminal Ready (DTR)" ???? <-- this is also a link to wiki artical

I think Mike was pretty clear in a previous post that the :

http://www.parallax.com/StoreSearchResults/tabid/768/List/0/SortField/4/ProductID/378/Default.aspx?txtSearch=usb+rs232

USB to Serial adapter from Parallax was the cheap and easy solution to the WIN7 to BS2 board connection.

With the old computer, it just sounds like the standard serial programming cable could be used.

Jim

Mike Green

Sorry. Data Terminal Ready (DTR) is the signal line used for resetting the Stamp or the Propeller to download a new program.

electrosys

I have tried this very cheap (about $1+ free shipping) USB to RS232 and it is working with my Propeller at (Windows XP) but I don't know if it will works with the BS2 and Windows 7,although at this price it is not a big lost.
Here is another one: http://cgi.ebay.com/USB-RS232-9-Pin-Serial-Converter-Cable-Adapter-D13-/320614587568?pt=LH_DefaultDomain_0&hash=item4aa61e5cb0