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Full ttl connects

Posted: Wed Feb 10, 2010 10:46 pm
by gcodori
I am interested in using the v-usb solution in converting an existing design from serial/parallel to usb. The existing design utilizes RTS-O, CTS-I, TX-O, RX-I. The schematic is posted at http://www.afticarr.com/FileDownloads/L ... TICARR.pdf

This is a simple connection between a computer and a model railroad control system. The PIC in the design is for traffic management, as lots of data is sent in most RR control systems.

All of the designs for USB solutions only include the TX and RX and not CTS and RTS. Is there a way to implement this in v-usb?

My goal would be to substitute the v-usb in a similar fashion as was done via bluetooth per this design http://www.kevinrowejones.com/locobuffe ... erBlue.pdf

I could buy a sparkfun USB solution that includes ALL ttl lines, but wanted a DIY solution.

Any thought?

Re: Full ttl connects

Posted: Thu Feb 11, 2010 9:14 am
by Grendel
Should be possible. You'll have to add some CDC/PSTN subclass specific control transfers, namely SetControlLineState (see PSTN120.pdf, 6.3.12) and GetSerialState (see PSTN120.pdf, 6.5.4). The document refered to is located at usb.org, in this archive.

Re: Full ttl connects

Posted: Thu Feb 11, 2010 8:43 pm
by gcodori
Unfortunately - my programming skills are next to zero. I was hoping that there may have been a way to access these like on the standalone chips (which all seem to be surface mount and harder to work with for the hobbyist).

GC

Re: Full ttl connects

Posted: Fri Feb 12, 2010 8:58 pm
by Grendel
V-USB is all about programming. Even if you use a more hardware oriented chip (like the ATmega32U4 <-- click this ) it's still mostly programming. It's the nature of USB.