In SX Microcontrollers, SX/B Compiler and SX-Key Tool, dkemppai wrote:

[quote="DosManDan"]
Been there, had the same problem. Read my post from a while back for the answer.

[url=http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=184217]http://forums.parallax.com/forums/default.aspx?f=7&p=1&m=184217[/url]

Hope this helps,
Dan (yes, another Dan with the SAME problem...hehe)[/quote]Dan, 
 

Thanks for the reply. I read through the thread, and I don't think it's a capacitance issue, but I will do some testing tonight. I have a multi layer board, with no resonator or feedback resistor installed. The board has very short traces. On board, there is a 3.0Volt regulator, and that is supplied with an external regulated 5.0Volt supply. (Very stiff, good bypassing, no noise...  ...I checked it with an O-scope) 

 

Although, I did start thinking last night that the oscillator settings could be interfearing with the debubbing. I'm starting to think this because the chip progammed the first time without any trouble, after that, if I remove power I need to bump it with 5 volts before it will program again. Also, if I remove power, and reattach it, the current draw is up a bit. Almost like the oscillator is 'stuck' or something. (Just a guess). 

 

 

Guenther,

Yes, I know that the Key needs 5 volts. I have a custom board with the SX on it. It has a pin header for the Key with 5 volt supply, and 3.0 volt regulator for the SX chip. (This will normally be a battery powered device, with DC-DC regulator supplying 3.0Volts to the SX and other chips. For testing/programming and docking it is powered with a 5 volt supply that has a linear 3.0 volt regulator and ORing circuit supplying the 3.0 volt rail. I checked everything with a scope, and I'm pretty it isn't a power issue...  

 

What would really help, is if I knew what to look for on the osc pins. What are the expected voltage levels/thresholds? What's normal for debugging?  Could the oscillator settings be involved here, maybe the drive levels are forcing the voltages on the osc pins, and tricking the debugger into thinking the chip has a resonator installed? 

 

I'm sort of grasping at straws here... 

 

Peter,

 

Yeah, no resonator/feedback/parallel capacitors installed here. This is the first 3.0Volt device (1/2 dozen 3.3 volt devices...). I've never seen this before now, so this problem new to me. 

 

 

Thanks!

Dan

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