18f4550 Device not recognized

[garethconner]

Hi all,

Today was my first day taking a crack at testing an 18F4550 as a USB device. My first attempt was to get the PICBasic Mouse demo application working, but so far no luck.

The only oscillator I have lying about is 6MHz, so I was trying to run the chip as a low-speed device. However, when I plug in the USB cable Windows throws a message stating that the 'Device is not recognized'.

I read through the USB.txt file and changed a single line in the MOUSEDESC.ASM file (commented out the hi-speed line and uncommented the low-speed line). But perhaps I'm missing some other configuration settings? Or is this more likely a wiring issue?

Thanks for any pointers.

Best,
Gareth

[garethconner]

To be more specific, in MOUSEDESC.ASM I made this change:

;#define UCFG_VAL _PUEN|_TRINT|_FS|MODE_PP ; Full-speed
#define UCFG_VAL _PUEN|_TRINT|MODE_PP ; Low-speed

Best regards,
Gareth

[mister_e]

I think You'll need to change your configuration fuses as well.

I'll suggest you to have a look at the following thread, USBDemo is probably something you want to give a shot.
http://www.picbasic.co.uk/forum/showthread.php?t=7760

[garethconner]

Hi Steve,

Thanks for the tip. I'll read through the thread you linked to, I'm sure that'll help.

I appreciate the response, thanks for your help.

Best regards,
Gareth