USBDemo, something to learn USB a little bit

[mister_e]

Well, one in the list... 18F4550, 2550,2455, 4455 they all works.

As you'll see, it's fun to have it's first working USB project....even if you're aware of post #7 and #8

[kiwipiper]

Hopefully this Topic is still alive as I am really keen to do some experimenting with USB.

I have looked at all the posts and haven't found any refering to my problem.

I am using the 18F4550 pic, Picbasic Pro 2.50 and MicroCode Studio Plus 3.0.0.5

When I compile it stops on Line 81

Line 81: UCFG var byte EXT ' include UCFG register... Yeah Melabs didn't (
Line 82: ucfg = %00010100 ' enable internal USB pull-up, Full speed USB

With the following Error Message:

ERROR Line 81: Redefinition of VAR. (USBDemo.pbp)

I notice that when I paste the code from mister-e's zip file into MicroCode Studio it changes the case of line 82:

Line 81: UCFG var byte EXT ' include UCFG register... Yeah Melabs didn't (
Line 82: UCFG = %00010100 ' enable internal USB pull-up, Full speed USB

the ucfg is now in Capitals, I don't know if this has anything to do with it?

[Darrel Taylor]

Previous versions of PBP didn't have the UCFG register defined in the include files. And usbdemo was written at that time.

PBP 2.50 does have the UCFG register, so defining it in the main program causes a "re-definition" error.

Just comment out the UCFG var byte EXT line and the error should go away.

hth,

[kiwipiper]

I am using the 18F4550 pic, Picbasic Pro 2.50 and MicroCode Studio Plus 3.0.0.5

When I compile it gives the following errors.

Error[118] c:\progr~1\mecani~1\mcs\usbdemo.asm 87 : Overwriting previous address contents (0000)
Error[118] c:\progr~1\mecani~1\mcs\usbdemo.asm 87 : Overwriting previous address contents (0001)
Error[118] c:\progr~1\mecani~1\mcs\usbdemo.asm 93 : Overwriting previous address contents (0000)
Error[118] c:\progr~1\mecani~1\mcs\usbdemo.asm 93 : Overwriting previous address contents (0001)
Error[118] c:\progr~1\mecani~1\mcs\usbdemo.asm 98 : Overwriting previous address contents (0002)
Error[118] c:\progr~1\mecani~1\mcs\usbdemo.asm 98 : Overwriting previous address contents (0003)
Error[118] c:\progr~1\mecani~1\mcs\usbdemo.asm 99 : Overwriting previous address contents (0004)
Error[118] c:\progr~1\mecani~1\mcs\usbdemo.asm 99 : Overwriting previous address contents (0005)
Error[118] c:\progr~1\mecani~1\mcs\usbdemo.asm 100 : Overwriting previous address contents (0006)
Error[118] c:\progr~1\mecani~1\mcs\usbdemo.asm 100 : Overwriting previous address contents (0007)

Are these errors anything to be concerned with?

Also out of interest, I am using a 4Mhz Resonator but in the code it is: DEFINE OSC 48

What is that about?

However, I seem to be making progress because when I plug it into the USB of the computer. I get the message found new hardware "USB Demo" but then it gives a message There were problems ........ etc etc.

The VB Application is not picking it up yet.

[Darrel Taylor]

When I compile it gives the following errors.

Error[118] c:\progr~1\mecani~1\mcs\usbdemo.asm 87 : Overwriting previous address contents (0000)
...

What to do if i get "overwriting previous address content" error message?
http://www.picbasic.co.uk/forum/showthread.php?p=6775

Also out of interest, I am using a 4Mhz Resonator but in the code it is: DEFINE OSC 48

What is that about?

The 18F/USB PIC's have an amazing oscillator/PLL structure.

With the proper CONFIG settings, You can use any crystal that's a multiple of 4mhz (4,8,12,16,20) and still have a system clock of 48mhz.

If the timing doesn't work well with your program, you can also have 48mhz going to the USB module, and 4/8/12/16/20/24/32 mhz going to the system clock.

It all depends on the CONFIG's.
<br>

[kiwipiper]

I commented out the four offending lines in the 18F4550.INC file and now don't get any errors. However, still get a error message from windows when I attach the PIC

Messages are: Found New Hardware. USB Device
USB Human Interface Device
A problem occurred during hardware installation. Your new hardware might not work properly.

I have tried USBDemo.exe and HIDmonitor.exe neither of these seems to see the PIC.

Any suggestions as to what I should try to do now to find the fault. At this stage I have not connected the push buttons or the trim pot to the breadboard but this shouldn't affect the pic being recognised as a USB device.

P.S. I have the USB connected to 18F4550 in the following way. D- to pin 23, D+ to pin 24 and the -ve usb connection and the USB case connected to vss. I have not connected the +ve usb connection to anything.

[kiwipiper]

Forget my last I have figured it out ....... a very happy man here.

I had left out the .47uF cap on Vusb. Connected this and all is working.

Will now have a serious play with it, which I sure will create a bunch more questions.

Thanks for all your help Darrel.