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A cheap easy Logic tool and USART

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be80be

Well-Known Member
Not wanting to have to unplug my pickit2 to use it to test with I tried out this
circuit after a long look at the pickit2 and junebug to see what I didn't need.
This is what I came up with it works real good for 3 channel logic tool uses the pickit2 software. And from what I have tried the UART works to. Here some pictures of it. And the circuit too.

And a shot of the logic tool working
 

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be80be

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That's the funny thing when I was trying it out I programed it with my pickit2 and when I plugged it in I open a new session. It comes up Ollhoss = id. 3v0 said you name it what ever you want. You can run two or three if you want
 

binzer

Member
Not wanting to have to unplug my pickit2 to use it to test with I tried out this
circuit after a long look at the pickit2 and junebug to see what I didn't need.
This is what I came up with it works real good for 3 channel logic tool uses the pickit2 software. And from what I have tried the UART works to. Here some pictures of it. And the circuit too.
The .1 and 100uf caps seem to be connected between two ground points on the schematic, must be a goof??
 
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be80be

Well-Known Member
It's not a goof the .1uF gos as close as you can get to the 18f2550 power pins. And the 100uf is close to the power from the usb. I just didn't see adding more tracks when that's the way it would be any way.
 

binzer

Member
It's not a goof the .1uF gos as close as you can get to the 18f2550 power pins. And the 100uf is close to the power from the usb. I just didn't see adding more tracks when that's the way it would be any way.
Trace your print, they are connected gnd to gnd, I posted because I thought you meant to put it between power and gnd, or is it just me cause I have not had my second coffee yet...
Mike.
 

BeeBop

Active Member
It's not a goof the .1uF gos as close as you can get to the 18f2550 power pins. And the 100uf is close to the power from the usb. I just didn't see adding more tracks when that's the way it would be any way.
No, Mike is correct Burt, have a look at your schematic... the caps are between Vss and Vss...
 

be80be

Well-Known Member
No big deal you no where they go I changed it sorry I should of checked it I just made that if some one else wanted to make it I fixed it
 

binzer

Member
No big deal you no where they go I changed it sorry I should of checked it I just made that if some one else wanted to make it I fixed it
Yup, Thats why I mentioned it. It's a nifty project, I want one! When I find a little time & money I'll make one.
Mike.
 

arhi

Member
There is bunch of unused pins on that 18F2550 ... maybe some patch to the firmware and another one to the win app can get this to show bit more then just 3 lines :D ... I checked out a firmware for a sec ... the logic analyzer routines is at the end of pickit2.asm and pickit.c .. had not time to look what do they do ... I assume they are using those 3 buffers that they usually use for script data to fill the scanned info ... not sure .. if someone has enough free time .. it would be cool ..
 
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