Quote Originally Posted by jellis00 View Post
I don't understand why the RA4 pushbutton doesn't operate like the others as a momentary switch. I checked the code and it appears it should. Is there some reason for this?
I also notice that the RX window continuously shows 10 line entries of "USBDemo" and when you click the Clear RX button, it immediately repopulates the RX window with the same 10 entries. I am trying to understand this...
The problem resolved itself and I don't know exactly why. The only changes I made were to make sure the pull-down resistors were enabled properly and to connect the RA0 pin to the potentiometer for the Analog A/D input. Either as a result of these changes or some other unknown reason, the annomaly of the RA4 pushbutton and the "USBDemo" messages in the RX window went away. I see now that the "USBDemo messages are not a result of the TMR0 reloads but only appear when the pushbuttons are pressed and the RX window clears normally now and stays clear until the next pushbutton.
Even though these problems are solved, I would still appreciate any inputs/ideas regarding my other questions. It begins to look like I can achieve my intentions for detecting USB connection by implementing the "self-power only" circuit as shown in Figure 17-11 of the 18F4550 data sheet. Will try it and report in later post.