SxKey Error Vpp

Rsadeika

I just got a "SxKey Error - Vpp generation failed" while trying to 'RUN' a program on my SX52 proto board. Anybody have any ideas what this means.

Thanks

Ray

Guenther Daubach

This message comes up when the SXKey can't generate the on-board 12V programming voltage for programming the chip.

The reason for that can be an additional external load at the OSC1 pin. Do you have an external clock generator connetcted to that pin?

Another reason can be a supply voltage below 5 Volts. If you have a multimeter on hand, measure the voltage directly at the Vdd and Vss header pins for the SX-Key - it should read 5 Volts, and its value should remain almost unchanged when programming starts. Should the voltage drop too much, replace the power supply by one rated for a higher Wattage.

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Greetings from Germany,

G

Rsadeika

Thanks Guenther,

I just tried your suggestions. I checked out the SXkey, it is still working; I tried programming another new SX52 proto board, it worked on that one. On the board that I am getting the error, I checked the voltages, I am getting 4.95, which by the way , I get on the new board that I tested. I tested the Vdd and Vss header pins for the SX-Key, and their was no drop, it remained at 4.95. I know I will probably have to can it, but I am curious as to why I am getting the error when all the voltages seem to be the correct ones. Anybody have any more ideas.

Thanks

Ray

Guenther Daubach

Ray,

seems as if the load (internal resistance) on the OSC1 pin is too high, so that the programming voltage generated by the SX-Key breaks down. Actually, the SX-Key itself monitors this Vpp voltage, and when it finds it to be too low it generates this specific error.

When you can successfully program another new SX52 proto board, it is most likely that the SX on the other board is the troublemaker, maybe due to some ESD into the OSC1 pin. Before putting it into the thrash, you might consider using this board for training your SMT soldering skills.

Un-soldering the SX52 is pretty easy using a hot air gun with a small nozzle. Move the nozzle constantly along all SX52 pins until the solder melts all around, and then use some pliers to remove it. Possibly you have also heated up the filter caps, and they were already blown off the board, so you will have to replace them later. For training purposes, you might consider soldering the damaged SX52 back to the board again, or - is you are brave enough - a new one. Good luck!

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Greetings from Germany,

G

Rsadeika

Thanks again for the suggestions. I will not be throwing the board away, I can still use it as a regulated 5V power supply. I am now thinking how hard it would be to solder on a 28 pin connector and have another SX28 programer, or ...

Ray

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