Objective Development Forums

Posted: **Tue Mar 01, 2011 12:38 am**

I'm trying to get the custom-class example to work with an atmega324p. I can compile and flash the firmware without issue, but the set-led program doesn't work.

I went through and modified the files so the appropriate fuse bits are set, and the appropriate pins are chosen for D+ and D-

The full error I get is:
"Could not find USB device "LEDControl" with vid=0x16c0 pid=0x5dc"

When I run lsusb:

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johnny@picard:$ lsusb

Bus 002 Device 025: ID 16c0:05dc VOTI USBasp AVR Programmer

Bus 002 Device 005: ID 03f0:2504 Hewlett-Packard 
Bus 002 Device 004: ID 06a3:8021 Saitek PLC Eclipse II Keyboard
Bus 002 Device 003: ID 058f:9254 Alcor Micro Corp. Hub
Bus 002 Device 002: ID 045e:00d1 Microsoft Corp. Optical Mouse with Tilt Wheel
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 010: ID 0781:74c3 SanDisk Corp. 
Bus 001 Device 003: ID 0c0b:b159 Dura Micro, Inc. (Acomdata) 
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub

A more detailed dump:

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Bus 002 Device 025: ID 16c0:05dc VOTI USBasp AVR Programmer
Device Descriptor:
  bLength                18
  bDescriptorType         1
  bcdUSB               1.10
  bDeviceClass          255 Vendor Specific Class
  bDeviceSubClass         0 
  bDeviceProtocol         0 
  bMaxPacketSize0         8
  idVendor           0x16c0 VOTI
  idProduct          0x05dc USBasp AVR Programmer
  bcdDevice            1.00
  iManufacturer           1 jferg.net
  iProduct                2 LEDControl
  iSerial                 0 
  bNumConfigurations      1
  Configuration Descriptor:
    bLength                 9
    bDescriptorType         2
    wTotalLength           18
    bNumInterfaces          1
    bConfigurationValue     1
    iConfiguration          0 
    bmAttributes         0x80
      (Bus Powered)
    MaxPower               40mA
    Interface Descriptor:
      bLength                 9
      bDescriptorType         4
      bInterfaceNumber        0
      bAlternateSetting       0
      bNumEndpoints           0
      bInterfaceClass         0 (Defined at Interface level)
      bInterfaceSubClass      0 
      bInterfaceProtocol      0 
      iInterface              0 
Device Status:     0x0000
  (Bus Powered)

The product name appears to be correct.

I'm measuring 2.75V on the D- line, and 0V on the D+ line. This is just with a standard multimeter.

Posted: **Tue Mar 01, 2011 3:47 am**

I've tried with an ATMEGA48 now. Same problem.

I've checked the voltages at D+ and D-. D- is at 2.7V, D+ is at 0V. The uC has 5.05V.

Can someone give me ballpark figures on the voltages I should be seeing?

Additional details:
Ubuntu 10.04
libusb1.0 and 0.14 installed (might this cause a conflict of some kind?)

I noticed `libusb-config --cflags` didn't return anything, so I modified the makefile to include -lusb in the compiler flags (for the set-led program)

Thanks for your time. Sorry if I seem impatient, I just got all my parts today, and I'm quite excited. It's just a shame that I have to work through so many strange errors. :lol:

Posted: **Tue Mar 01, 2011 4:22 am**

A picture in case it helps:

(click to enlarge)

Posted: **Tue Mar 01, 2011 9:31 pm**

I see you are using a USBasp programmer, could it be that the VID & PID are the same as LEDcontrol? I know Windows has a problem with this scenario but not too sure about Ubuntu. Try re-booting without the programmer connected and see if that makes a difference.

Posted: **Fri Mar 04, 2011 12:13 am**

Okay.... for posterity, the program has to be called with sudo.

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sudo ./set-led status

not

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./set-led status

D'OH! I wonder why this is. I guess my OS isn't automagically allowing the device to be accessed by regular users. I know there are programs to allow users to access things like USB drives, or cameras, but I guess by default hardware access is restricted to root. If anyone could explain or elabourate on that, I'd be grateful.

At least it's working!

Let the hacking begin.

Objective Development Forums

Could not find USB device "LEDControl" (atmega324p)

Could not find USB device "LEDControl" (atmega324p)

Re: Could not find USB device "LEDControl" (atmega324p)

Re: Could not find USB device "LEDControl" (atmega324p)

Re: Could not find USB device "LEDControl" (atmega324p)

Re: Could not find USB device "LEDControl" (atmega324p)