USB question

Thread Starter

CircuitNewbie

Joined Dec 20, 2009
15
Thanks Sgt, your definition really give in-depth view the profound world of electronics to newbie like me...

Your help is very much appreciated. :)

I am now having issue getting the hardware for my PIC18 chip to work with the USB interface. I am using PIC18F14k50/PIC18F13k50 chip and had attached the connecting method for USB powered communication with my laptop. However, whenever i connect the circuit into my USB port, it will show that the USB Device is malfunctioned. I am sure that the correct usb driver is already pointed to, so that windows can install it. I am using "Simple USBLib" method to talk between the windows software and the PIC18 firmware...

The part that i am unsure is the hardware fixed-up of the PIC18, i had use the development kit schematic as a reference to derive the hardware circuit connection, but it still does not worked... :(

I had also tried the following:
- change the 150Kohm pulled-up resistor to 1.5kohm,
- removing the pull-up resistor
but all gave the same result as the device is shown as "unknown device" in the window hardware device page... :(

Please do kindly assist to advice if anybody has experience in setting up the hardware for PIC processor...

Thanks in advice... :)
 

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Thread Starter

CircuitNewbie

Joined Dec 20, 2009
15
Dear Sgt,

Thanks for moving the post to the correct forum... :)

I had read some other treads and updated the diagram as per attached, but the circuit still does not work...

I am at my ends, and really have no idea what could have been wrong. Hope that some kind soul out there can provide me with some advice... :(

Any preciously advice would be appreciated.

None the least, wish all a happy new year! :)
 

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SgtWookie

Joined Jul 17, 2007
22,201
Dear Sgt,

Thanks for moving the post to the correct forum... :)
I didn't move it here; Beenthere did. I am merely another peon in these forums, and have no God-like powers. ;)
I had read some other threads and updated the diagram as per attached, but the circuit still does not work...

I am at my ends, and really have no idea what could have been wrong. Hope that some kind soul out there can provide me with some advice... :(

Any preciously advice would be appreciated.

None the least, wish all a happy new year! :)
I can't advise you as to the proper wiring or programming of your particular PIC. It doesn't look improper to me, but I really have no frame of reference. Hopefully, someone else will respond who has more knowledge in this area.
 
Last edited:

n9352527

Joined Oct 14, 2005
1,198
The schematic shows that you connected the VUSB pin to pin 1 of USB connector. I don't think that is correct, because that is the reference voltage for USB signal and not power pin. There shouldn't be anything connected to that pin, except the capacitor.
 

Thread Starter

CircuitNewbie

Joined Dec 20, 2009
15
Dear n9352527,

You are really my saviour!!! ;)

The issue that troubles my sleep for the past whole week had finally been cleared!! The circuit finally works!!! :D

Thanks alot, wishing you and your family a fruitful year ahead!!!

Best regards! :)
 

Thread Starter

CircuitNewbie

Joined Dec 20, 2009
15
I didn't move it here; Beenthere did. I am merely another peon in these forums, and have no God-like powers. ;)

With your knowledge and willingness to share, you are already helping alot ppl out here... :D
Many of us are grateful for your involvement. ;)

I can't advise you as to the proper wiring or programming of your particular PIC. It doesn't look improper to me, but I really have no frame of reference. Hopefully, someone else will respond who has more knowledge in this area.
You already helped alot with the previous circuit... Wish you a better year than the last one... ;)
 

blueroomelectronics

Joined Jul 22, 2007
1,758
Pin 17 VUSB should only be connected to a 0.47uF cap. You may have damaged it by connecting it directly to USB 5V power.
 
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