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Topic: Can someone please explain CTS RTS UART (Read 13994 times) previous topic - next topic


I looked at their pic code again - it tries to use 115200, 57600, 19200 and if none of those are possible defaults to 9600.


No, they didn't. They did say that the vdrive2 defaults to 9600 baud for reverse compatibility. I believe we are going to have to either change the boot loader or send it a message during setup to change that rate. there is something in the host control documentation about setting the baud rate with dos commands.

here is the firmware documentation which discous's dos comands, this should be valid for all Viniculum device sense they all use the same firmware.
page 29 covers changing the baud rate.

I also just found a guide to changing/reprogramming the firmware, in here it talks about picking a baud rate for programing and says a 1m is the most optimum baud rate. I'm sure they were talking about changing the code on the vdip at 1m not writing to a usb device but it does say that flash memory can not go faster then 1m. so that might be our speed limit. anyways thats around page 5

I think everything we need to know to figure this out is in those two documents, its just a matter of sifting through them now.
So it may need to actually be done in the boot loader itself.

Sorry for the late response, I've been side tracked by finals.



this should be valid for all Viniculum device sense they all use the same firmware.

Ah, no they don't.  There are several flavors of the firmware (a glance at the firmware download page shows 6), and I wouldn't count on them being 100% compatible.

Most likely the stuff we'll deal with has the VDAP firmware, but check.  The way things are changing, I'd make sure the version number of the firmware and the version number of the firmware documentation match as well.


sti robot

Apr 29, 2008, 03:28 am Last Edit: Apr 29, 2008, 03:34 am by sti_robot Reason: 1
I did some testing tonight to see how much I could force through the device without error.  If I use a 60 ms delay between writes I get almost no errors.  This translates to about 112 milliseconds between writes.  ~9 times a second isn't good at all for logging a moving vehicle.  For reference ~10 Hz is the rate you would expect from OBD II.  OBD II is considered to have a fairly low sample rate.

Next I'll try out tweaking the baud rate, i guess.

sti robot

I know no on bumps threads on this forum...but has anyone come up with anything new for the VDIP?  Got it working reliably?


i've successfully used VDRIVE2 with simply tying CTS to RTS directly with a jumper wire.  every time VDIP says it's "ready to send," it gets "clear to send" msg back.  note that according to http://www.arduino.cc/playground/Main/UsbMemory this might be a problem if sending messages/data too quickly.  not sure what that means exactly in terms of timing, but YMMV.


Take a look at http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1269839540

Hopefully, this is helpful and accurate and will help explain how to use CTS/RTS.

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