Very strange USB port problem

portreathbeach

macrumors member
Original poster
Feb 19, 2011
65
0
I have been a Mac user for many years and have come accross a strange problem with a USB device.

I do a lot of PIC microprocessor programming and have been using a PICKit3 (USB programmer) for a few years now. A week ago, the PICKit3 stopped working or being detected by the computer. I bought a new one and plugged it in. MPLabX, the programming software 'sees' the programmer, but when I go to actually use it, the software eventually says that it cannot connect to the programmer.

Now, here's the strange bit. If I plug the programmer into one of the USB ports on my wired keyboard, it works fine. I thought tat it may have been a problem with one of the USB ports in the rear of the machine, so I removed the keyboard and plugged the programmer into the port it was in, still does not work.

I then re-connected the keyboard and put the programmer into one of it's USB ports and again, it works. What can be causing this?

Any help would be great :)
 

portreathbeach

macrumors member
Original poster
Feb 19, 2011
65
0
I've been using it on this Mac for the last 2 or 3 years.

Ok. After a chat with Apple, I have got it to work.

If I have my USB card reader and the PICKit3 in the back, the PICKit3 doesn't work. If I have one of them plugged into the wired keyboard USB port on the side and one plugged in the back, they both work!

They both have been working fine together for the last couple of years in the back, so I don't really know why they would stop working now.
 

portreathbeach

macrumors member
Original poster
Feb 19, 2011
65
0
The strange thing is, I have tried every port on the back with the keyboard, an old wired mouse, flash drives and hard drives and it's only the PICKit3 which doesn't work.

When it's plugged in, the software can see it, and knows it's there, but it won't work. I can't understand how it works when plugged into one of the USB sockets on the keyboard though!
 

matreya

macrumors 65816
Nov 14, 2009
1,286
127
A possible reason it's working in the keyboard is that the keyboard is a USB hub... have you updated System software recently?
 

portreathbeach

macrumors member
Original poster
Feb 19, 2011
65
0
I updated to Yosemite a while back and haven't changed anything recently. It just stopped working.