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Questions re original AD2USB Serial Adapter

PostPosted: Mon Jul 21, 2014 3:51 pm
by peterd
Hi -

I have an AD2USB with the original serial adapter (MAX3232 TTL converter in the DB-9 headshell). I bought this to use with a WIZnet serial <-> ethernet bridge. While I've used it a number of times directly connected to my laptop, I never got around to getting the WIZnet setup going.

Now, having a spare Raspberry Pi on hand, I'd like to use the USB interface of the AD2USB (the RasPi's serial port will be used to connect an Ademco 4100SM).

I can't seem to find any documentation on the AD2USB + serial adapter combo. So my questions are:

1. Do I have to do anything other then disconnecting the serial line from the AD2USB board in order to restore the use of the USB connection?

2. Do you see any reason why I can't repurpose the serial adapter to do the TTL conversion from the RasPi's GPIO pins (my understanding is that the MAX3232 chip handles 3.3 V as well as 5 V signal levels)?

Thanks in advance,
Peter

Re: Questions re original AD2USB Serial Adapter

PostPosted: Tue Jul 22, 2014 9:44 pm
by mathewss
Hay! thanks keeping in touch. I love it when technology keeps on a ticking and ya that adapter is very RE-usable and IMHO everyone doing such tinkering needs one in the toolkit.

Memory fades....
I made a few versions of the serial adapter for the AD2USB depending on the version of the AD2USB. I had a 5v version and a 3v3 version.

If yours connects to the PCB via a 10 pin connector then its the latter the 3v3 version although I think this chip will do both but the person I was ordering these from gave me different chips over the years so look at the specs on the chip to confirm the voltages but in any case I am sure it can work to 5v with no possible damage and at 115200 for the Pi serial console the speeds would not likely be any issues.

This adapter should be perfect for using with the raspberry PI or BeagleBone Black just double check the voltages the chip can take and give it a try. I still have a few of these if you ever need one I can give you a good deal if you don't make me solder them by hand like I did yours :c)

Re
Sean M