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I've either been up too long, or in desperate need of some more coffee... just misread "two diodos " as something completely different!
As long as you have a common 0v, it shouldn't matter how many different supplies you have. Are you overloading your Regulator? When everything is connected (and not working) what is the +V on each device?
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This morning i put 2 regulators, but the problem still happens.
I thing that iīm not overloading my regulator. I'm using 7805 that supports 1A.
With this morning tests i think that my problem itīs with my 74HCT245. And why? When i put 4.3V on my 74HCT245 i donīt have problems in the display. I see the datasheet and thereīs a diference between 74HCT245 and 74HC245. For HC the condition is VI = GND to VCC For HCT the condition is VI = GND to VCC - 1.5 V. Whatīs this meaning? That i cannot put Vcc to +5V or my inputs/outputs have to be 5-1.5=3.5V????
Melanie said:
When everything is connected (and not working) what is the +V on each device?
In each device i have +4.9V.
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As i said i'm giving more news...
I changed my 74HCT245 to 74HC245 and i have no problems... I donīt understand very well but it works!
Now i only have one problem
My MCLR has the circuit attached, but when i close my circuit almost the time doens't do the reset. But if i put my multimeter between pins 1 (MCLR-Vpp) and ground, to measure my voltage it works fine...
What probably it's happening??
What can i do?
Sorry to have strange questions and strange problems, but i'm new in this matter and i like to understand the problems.
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leonel, With the diode in the direction that it is the Processor will never reset with the pushbutton. What is the reason for the diodes direction?
Dave Purola
N8NTA
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In datasheet of 18F458 pag 23 section 3.0 (Reset) thereīs a schematic. I did a little changes to use a switch and make a reset through a switch... Itīs not the first time i'm using this circuit and in the others have been working!
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I still prefer the KISS engineering... but it's my own opinion.
how about something like that
<img src="http://www.picbasic.co.uk/forum/attachment.php?attachmentid=394&stc=1">
you can remove the toggle switch...
In fact to do ICSP i use the above in conjunction with a simple ICSP switcher like that
<img src=http://www.picbasic.co.uk/forum/attachment.php?attachmentid=163">
This allow me to do everything for developpement without install/remove the ICSP connector.
Last edited by mister_e; - 1st August 2005 at 18:34.
Steve
It's not a bug, it's a random feature.
There's no problem, only learning opportunities.
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Hi, leonel
Try a Schottky diode ( BAT 85 i.e. ) or Germanium diode ( OA ...) instead of the 1N4148 ... its leakage current will make your reset circuit work better !!!
that's not very elegant ...but will work !!!
Alain
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What i did and it works was putting a R=100K between pin 1 and ground, in conjunction with my circuit.
What's the "KISS engineering"?
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