USB not working

Storic · Joined: 03 Dec 2005 Posts: 182 Location: Australia SA

HI I an using V4.023 and 3.249 CCS compiler, on a board that I had put together. Using the demo program "ex_usb_hid.c" on the USB Demo board (18F4550) all works OK and the PC can see the USB (with errors). when I put the same program into my board (can not see at all), using the USB drawing supplied, pin 2 to C4 pin 3 to C5, when I traced out the USB demo board I found the reverse, Pin 2 to C5 and Pin 3 to C4, (what to do with 400 land fill PCB), (I an using the USB B Mini) for the USB Plug. I reversed the connection on my PCB by cutting tracks and soldering jumper wires, Yep working now Evil or Very Mad

Andrew
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Ttelmah · Guest

I'm sorry, but the connections are not reversed in the drawing....
The USB 'B' socket, has the pinout running:

2 1
3 4

As you look 'into' the socket,

and

3 4
2 1

Looking at the base of the socket, from below the board. Notice the row reversal.
Pin 3 on the socket, goes to C5 on the processor (pin 43), and pin 2 on the socket, goes to C4 on the processor (Pin 42 - the circuit diagram is slightly confusing, since the pin locations on the drawing of the processor, do not correspond to those round the real chip...).
I'm afraid you just laid the board out wrong...

Best Wishes

Storic · Joined: 03 Dec 2005 Posts: 182 Location: Australia SA

Yes you are probably correct, not only this, I cant get the USB to work at All. even on my USB Dev kit. Programs OK, code in OK, USB ???. not to worry, I will try another 18F4550 micro. Sad

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Storic · Joined: 03 Dec 2005 Posts: 182 Location: Australia SA

I found the reason why my USB was not working, it appears that I have my tracks to close together, pin connection was OK, Using external wires to of board mini USB B connector (4 pin) it work with out any problems. was not an easy one to find where after careful review of the circuit connection every think was correct Confused

Now I found the cause, the fix is easy ? Shocked

**** not the tracks "found a short on C3 to ground" the Vbus Cap pin****

Andrew
_________________
What has been learnt if you make the same mistake? Wink