peter green wrote:
>> Has anyone an plausible explanation for this kind of behaviour ?
>> Or has anyone seen such behaviour before ?
>>     
> i've had something similar with my picsquirt programmer, if unplugged and plugged in again rapidly it often fails to come up properly, if left for a couple of hours after this it starts working fine.
>
> i guessed it wasn't resetting properly or something and stuck a 1K bleed resistor on the power rails, since then i have had no issues with the one that has the bleed resistor fitted. 
>
>
>
>   
As for the "Bleed" resistor... I have a 10F part (in fact, all my 10F 
parts), They seem to be such good power efficient devices and all, that 
they do not drain the capacitance in the bypass cap in a long time, and 
even without a cap, it does not reset for a while. I have a 1M "bleed" 
resistor in my breadboard right now. Seems to be more common than I 
thought. The application is a wireless transmitter with a momentary 
switch on Vcc... PIC starts up, transmits, then sleeps. Without a bypass 
cap, I measured about 5 seconds from when I stopped pressing the 
momentary, and when the PIC would get a low enough Vcc for another press 
to reset it. I guess the breadboard has enough capacitance to provide 
enough charge for the 10F to still sleep, and not reset. As I say, 1M 
resistance was enough between Vcc and Vss pins of the 10F to avoid the 
problem.

Rolf
-- 
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist