USB Pics, ICD2, pic basic pro

[vacpress]

Hey!

Thanks. I actually just ordered some products from Winford. Fair enough prices on some stuff I need.

So, I managed to get as far as 'unknown USB device' in win xp pro sp2 when using the microchip bootloader files. I found a compiled .hex for the 18f4550 on the forums here somewhere.

When I specifiy the correct device driver, it refuses it, prefering to be unknown. Jerk.

Any insights on this? I should note that Ive got a 10pf cap pulling pin 18(usbv) to ground, not the specified 470nf. 10pf is the smallest ive got!

Thanks!

[Darrel Taylor]

That capacitor is probably the culprit.

It's there to stabilize the 3.3V Voltage Regulator for USB.

10pf is way too small. 0.22uF is recommended, but I've used .1uF once only because I didn't have a bigger one handy at the moment.

A larger capacitor will work fine, 1uF, 4.7uF whatever you have. It's just there for a filter.

[vacpress]

as i am about to go grab a bigger cap to try, let me ask, why do the schematics show a 470nf cap here then? isnt that much smaller than .22uf?

thanks!

[Darrel Taylor]

  .000000470000
     |  |  |  |
mili-/  |  |  |
micro---/  |  |
nano-------/  |
pico----------/

470nf = .000000470 F = .47uF = 470,000 pF
220nf = .000000220 F = .22uF

.

[vacpress]

I tried again with a 2.2uf. Sadly, no improvement. It continues to act the same on both available test systems. I am using a 20mhz ceramic resonator, is it possible this is a problem?

the 20mhx resonator has worked fine for other projects and it also runs the blinky led test on the 18f4550...

thanks! i really am not a lazy question asking *******... ive probably spent 20 hours on this in the last 4 days...

-robert

(p.s. i am trying to usb-ize some of my future projects, wanna see past stuff? the electronics are buried in the list. www.robertguyser.com)

[vacpress]

oi!

those stinking cap ratings and markings are madening!

thanks for the 101!

aaand, just in case someone who is also wanting to know about the icd2 and 18f4550 runs into this thread; they do work well together, not sure what debug features will work, but it programs the sucker.

[Darrel Taylor]

I am using a 20mhz ceramic resonator, is it possible this is a problem?

For 20mhz, what do your CONFIG's look like?

Here's an example from Bruce.
http://www.picbasic.co.uk/forum/show...85&postcount=4

[vacpress]

So. I am now attempting to use the code from Mister E's awesome looking USBDemo thread (http://www.picbasic.co.uk/forum/show...hlight=18f4550)

I cannot get PBP code to compile through microcode studio, i get "Overwriting previous address contents (xxxx)" then it says 'too many errors quitting. I am using mpasm. Grrr

In the meantime, I have loaded the included .hex file and unfortunately i still get the same results. It is, I suppose that is a good sign... Any idea what it means? I dont have enough experience to troubleshoot this stuff, hence the posts. I gather USB is asking what the device is, and it isnt able to tell it. I know there is also something about enumeration failure, but i do not think this is the same..

??

continued thanks

[Darrel Taylor]

mister_e's example was setup for a 4mhz crystal. You'd have to modify it for 20mhz.

"Overwriting previous address contents (xxxx)" means that the CONFIG lines in the program are conflicting with the config lines in your 18F4550.inc file.

Which means you still need to answer post #11

[Darrel Taylor]

wanna see past stuff? the electronics are buried in the list. www.robertguyser.com)

Ha ha, that Vacuum Former you drew up, looks just like my old Vac-U-Form I had when I was a kid.
Except it doesn't have a handle on the front to pull down the vacum. And it's a little bigger.

Vac-U-Form by Mattel
http://www.spookshows.com/toys/vacuform/vacuform.htm