USBDemo, something to learn USB a little bit

[Darrel Taylor]

Pin 4 of the USB connector is Ground.
It and the Shield should be connected to VSS on the LAB-X1.

Have you removed the MAX232 chip?
You've set the RX pin to output, which is likely to cause high currents if the MAX232 is still there.

[Demon]

Pin 4 of the USB connector is Ground.
It and the Shield should be connected to VSS on the LAB-X1.
...

Tried both USB pin 4 (black wire) and the eyelet from the shielding connected to VSS, same garbles on LCD.

I used one of the VSS pins on the PIC, does it have to be a special VSS contact on the Lab X1?

...
Have you removed the MAX232 chip?
You've set the RX pin to output, which is likely to cause high currents if the MAX232 is still there.

I didn't remove the MAX232, but I installed headers on my Lab X1. The jumpers for RX and TX pins are disabled, same with VUSB pin.


EDIT: I didn't have the recommended capacitors so I used two 0.1uF ceramic caps in parallel across VUSB and VSS. Could that be a problem?

[Charlie]

I'm just getting started with USB. I've gone through the CDC demo and created my own variants with success (after a bit of teething pain) and now I'm trying to move on to HID. I've found the DT_HID260.zip file and I've been playing with the contents, but I'm not having any luck getting DT_HID260.pbp, DT_INTS-18.bas, ReEnterPBP-18.bas and my code to work together. I'm so close.... I think, but right now I can't even compile.

I've got 2 errors that have me completely stumped:
Illegal opcode (USB_INT)
Address label duplicated or different in second pass (INT_RETURN)

Any clues where to look? Many thanks...

[Darrel Taylor]

It sounds like you would also be getting an error that says it can't open include file DT_INTS-18.bas.

Did you put it in your PBP folder?

[Charlie]

Actually I just resolved it. It seems the line to include DT_HID260.pbp must come AFTER the INT_CREATE. I moved the include from the top of the file to this location and the errors went away.

Compiles no errors means it will work fine right? Well not exactly, but I'll chew on "why" by myself for a bit.

Thanks for the help!

[Charlie]

Well I though I'd leverage Darrel's heavy lifting and put the USB code (including the interrupt structure) together with the SD card code and make myself basically an overly complicated and expensive thumb drive, purely for my education. It seems, however, that the includes consume more than the 2K space for variables, and after about an hour of trying to make things less generic by eliminating variables wherever possible in favor of fixed values, I still don't have enough space. I'm also not sure if I'm even getting close - is there any way to have the compiler tell you how much you are over by, rather than simply "unable to fit"?

[Demon]

Charlie,

I had a similar problem once; so I copied the Includes in the code and removed all the variables I didn't need. That worked in my particular situation.

Robert