《Code and Life – AVR ATtiny USB Tutorial Part 3》.pdf

Home | Electronics | Raspberry Pi | V-USB tutorials | Reviews | General | Web coding January AVR ATtiny USB Tutorial Part 3 29 2012 Electronics , V-USB tutorials 159 Comments or trackbacks This is the third part of my USB tutorial for ATtiny2313 and V-USB library. In the second part we got the breadboard setup more or less covered, and now is the time for actual code! This will most likely be the longest of the three parts, so let’s get started. Adding V-USB as a part of your project First, we will download the latest version V-USB library from OBdev. Head to the Downloads-section and get the latest .zip – I got vusbzip. Unzip the archive and copy the usbdrv subfolder to your project folder (the whole folder, not j ust contents). Go to the subfolder and make a copy of usbconfig-prototype.h with the name usbconfig.h. Locate the #define lines for IO port and port bits and clock rate, and update them as necessary to reflect our configuration where D+ is in PD2 and D- in PD3 and clock rate is 12 MHz: #define USB_CFG_IOPORTNAME D #define USB_CFG_DMINUS_BIT 3 #define USB_CFG_DPLUS_BIT 2 #define USB_CFG_CLOCK_KHZ 12000 It’s also a good idea to ensure that V-USB tells the computer that it is powered via USB (i.e. not self powered) and takes maximum of 50 mA of power (defaults in my version is USB power, 100 mA max.): #define USB_CFG_IS_SELF_POWERED 0 #define USB_CFG_MAX_BUS_POWER 50 We will be using OBdev’s licenced vendor and device IDs, so they don’t need to be changed (note that this also means my tutorial will fall under GPL, including the schematic in part 2). But we do want to customize the vendor name and device name (note the backward slash in vendor name string used to split the #define to two lines so it fits into this blog post): #define USB_CFG_VE