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USB JDM with external power?

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loopyroberts

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jdm external power

Hi all, I am new to PIC programming and just made myself a JDM Programmer.

The programmer works perfectly through serial but I would like to be able to use USB so I can program it with my laptop.

I have a USB-RS232 cable but obviously that doesn't work. I realise that USB cannot supply enough voltage to MCLR to program properly.

I was just wondering if it would be possible to use an external power supply with the USB-serial input driving transistors that switch the external power on and off to the JDM. I'm not sure whether the transistors would be able to switch fast enough to keep the serial data clean.

Just keen to hear your thoughts.
 

usb jdm

Hi,
Using transistor to switch MCLR should be OK, remembering that MCLR remains steady during the whole of programming, there is no need to switch the signal too often. But I doubt if the problem is due to MCLR drive problem, since it takes very little current ? Even the latest JDM is using transistor to switch MCLR, vide their home page:

**broken link removed**

Regards,
Laktronics
 

jdm usb

Thanks for your reply, I might try pinning the MCLR to 13V and see if that works.
Maybe the 5V from the USB isn't quite enough,
Hopefully the programming signal doesn't need to be high as well.

Anyway, its something to try.
 

jdm external power supply

take a look at this i did't make this but think this may help u
 

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