Finally, the two most interesting parts. Note that this makes the pads narrower than the pins, so soldering will be harder. To program the board again, we do have to manually reset it into DFU mode, as mentioned earlier. What if we want to program the board again after this? The code below will defines the LED color to be red, yellow, and green as the device is powered on, enumerating, and ready, and purple if there is an error. I tested the board out in a USB socket and read the pin voltages, just to make sure the connector will work:.
||11 June 2009
||Windows NT/2000/XP/2003/2003/7/8/10 MacOS 10/X
||Free* [*Free Regsitration Required]
Install this driver via the Device Manager: Note that there are some traces pulling off in the center of the xplaim, which udb less than ideal. Its schematic was very zplain as an example to build a basic circuit. We need some way to re-activate the bootloader to program the board. Note also the impedance matching signaling resistors, and the capacitors paired with the crystal, the values of which I borrowed from the Uno rev.
If you want to change the fuses, you will need to use an ISP or other programmer. For these two weeks, I decided to understand the requirements to create USB-compatible device circuits and write the necessary software for a computer to talk to them. Since there are three of them, the natural thing would be to use them to display the state of Num Lock, Caps Lock, and Scroll Lock respectively.
One important note is that the entire chip has to be erased before you can run other commands on it.
At this point, the programming appears to be successful, but the LED is not blinking and the device still shows up with the DFU driver.
This has been a long post. Success Checking memory from 0x0 to 0x2FFF The project files are arranged as follows. LUFA focuses on a modular approach to this software, and comprises the following parts at a high level: Note that the compilation toolchain is basically the same, but the hex file is uploaded with dfu-programmer instead of avrdude.
This just temporarily enters the bootloader.
Weeks 11-12: AVR USB Devices and Programming
We can make the LEDs do something as well. Soldering really small packages to a board is incredibly difficult, and one of the main reasons is the initial positioning of the IC.
Jump to the bootloader section while the board is running, from program code. If all is working, programming is pretty straightforward:.
The traces on this chip are much too small avf solder individually. A correct value of 16 MHz, and this error went away. I strongly recommend this as a workflow! On the other hand, microcontrollers with hardware USB support offload the necessary computations to dedicated circuitry.
You can find a useful albeit somewhat outdated guide for this here. Adapting from the demo, the code for this is pretty straightforward:. Note that this makes the pads narrower than the pins, so soldering will be harder.
Installation of dfu-programmer is pretty straightforward. Different quartz crystals at the same frequency are not interchangeable; they are specced at a fixed load capacitance that must be matched by the circuit for the specified accuracy.
Weeks AVR USB Devices and Programming
This means that the binary operations are flipped: Finally, the two most interesting parts. The USB signaling pins require resistors for xplaim matching to optimize signal quality. This is where the USB hardware comes in. In order to mill traces for them, one will either need to use a 10 mil end mill, or edit the pads to allow for more space with them. Hardware or Software USB? Because I avd using some non-standard parts here, I found the Ladyada and Sparkfun Eagle libraries to be useful.