SX-KEY com failure

steve pearce

I'm trying to upload a program to a new SX I just recieved.· The problem is, it works some of the time but most of the time, the program gives a "SX-KEY not found on COM1" error or a "communications failure" about half·way through the loading process.· If I do get it to load,·when I single step or walk through the code, I get the same error, "SX=KEY not found on COM1", after 10 or so instruction executions.· I'm using windows XP and have tried every com port availiable as well as trying a new SX chip.· I also purchased the board in the kit.· Thanks for any help, Steve Pearce.

Bean

Are you using the SX-TECH board to program the chip ?
Bean.

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"SX-Video Display Module" Available Now.

www.sxvm.com

"A problem well defined, is a problem·half solved."
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PJMonty

Steve,

This is my standard reply for this problem:

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Go to the hardware manager and open the settings for the serial ports.
For the port that's attached to the SX-Key, check the FIFO settings.
Most likely it's something like 14/16 bytes. Set the values down to
something low like 3/4 bytes. I have found this often cures a number of
SX-Key anomalies such as random disconnects. You might even want to
experiment with turning the FIFO off. I know the FIFO is a nice thing
to "take the strain" off the CPU, but when everyone is running 800 MHz
and up CPUs, I find the CPU can handle the burden.

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This is a bigger problem in XP than in the other versions of Windows. It is also something is being addressed in the update to the IDE that is still being worked on. While the above solution doesn't always work 100%, it usually minimizes the problem. As for when the new version will be coming out, I can only ask for a little more patience.

Thanks, PeterM

Guenther Daubach

Steve,

in addition to what Peter advised, I experienced similar errors when Vdd was off the specified 5 Volts. Although a stand-alone SX works fine between 2.7 and 5.5 Volts (depending on the clock frequency), the SXKey does not. So you shoud check the supply voltage to make sure that it is close to 5 Volts.

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Greetings from Germany,

G

Jim Palmer

Steve,

To add to Guenther's message I originally had the same problem where I had 5Volts showing while the SX was running and not being programmed. However, as soon as I started to program the chip, my power supply was unable to generate the necessary amps and keep up the 5Volts of operation. In other words, you have to check the voltage while it is being programmed, not while it is sitting idle or running a program.

Hope one of these tips helps,
Jim

steve pearce

Thanks for all the help.· I have narrowed it down to a noisy power supply.· Again, thanks for all the help, Steve Pearce.