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[Lcdproc] CWLinux 12832 Keypad Issues


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  • From: mike at theptrgroup.com (Mike Anderson)
  • Subject: [Lcdproc] CWLinux 12832 Keypad Issues
  • Date: Sun, 08 Aug 2010 11:10:09 -0400


> Hi all,
>
> Just a little findings.
>
> Under Ubuntu, I have got LCDd + lcdproc are running at the same time. I
> also run 'cat /dev/ttyUSB0' on another terminal. When I press key on
> cw12832, I have got missing input characters from terminal. However, I
> don't see any missing input if I don't have LCDd running.
>
> -Andrew
>
>

Actually, I *do* see characters dropped using minicom and the cw12832 at
19,200 Kb/sec. There appears to be a definite limit to the speed at
which you can press the keys and still have the uP on the display be
able to keep up. E.g., 1/sec seems to work OK most of the time. But,
if you press the keys any faster, say 2-3/sec, you'll easily drop a key
press or two (or three). So, something like 5 keypresses in 2-3 seconds
will yield only 3-4 actual characters on the port. Now, I've used
PL2303 USB/serial adapters at 230 Kbps reliably on this system. So,
it's not the PL2303 driver or the computer. I think we're just
outrunning the uP on the display.

Mike

--

---------------------------------------------------------------
Mike Anderson 703.585.9384
CTO/Chief Scientist mike at ThePTRGroup.com
www.ThePTRGroup.com Embedded, Real-Time Solutions
---------------------------------------------------------------
"Software development is like making a baby.
You can't make a baby in one month by impregnating nine women.
Some things just take time."





  • [Lcdproc] CWLinux 12832 Keypad Issues, Mike Anderson, 08/08/2010

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