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diff --git a/usbdrv/Readme.txt b/usbdrv/Readme.txt deleted file mode 100644 index 970dc66..0000000 --- a/usbdrv/Readme.txt +++ /dev/null @@ -1,172 +0,0 @@ -This is the Readme file to Objective Development's firmware-only USB driver -for Atmel AVR microcontrollers. For more information please visit -http://www.obdev.at/vusb/ - -This directory contains the USB firmware only. Copy it as-is to your own -project and add all .c and .S files to your project (these files are marked -with an asterisk in the list below). Then copy usbconfig-prototype.h as -usbconfig.h to your project and edit it according to your configuration. - - -TECHNICAL DOCUMENTATION -======================= -The technical documentation (API) for the firmware driver is contained in the -file "usbdrv.h". Please read all of it carefully! Configuration options are -documented in "usbconfig-prototype.h". - -The driver consists of the following files: - Readme.txt ............. The file you are currently reading. - Changelog.txt .......... Release notes for all versions of the driver. - usbdrv.h ............... Driver interface definitions and technical docs. -* usbdrv.c ............... High level language part of the driver. Link this - module to your code! -* usbdrvasm.S ............ Assembler part of the driver. This module is mostly - a stub and includes one of the usbdrvasm*.S files - depending on processor clock. Link this module to - your code! - usbdrvasm*.inc ......... Assembler routines for particular clock frequencies. - Included by usbdrvasm.S, don't link it directly! - asmcommon.inc .......... Common assembler routines. Included by - usbdrvasm*.inc, don't link it directly! - usbconfig-prototype.h .. Prototype for your own usbdrv.h file. -* oddebug.c .............. Debug functions. Only used when DEBUG_LEVEL is - defined to a value greater than 0. Link this module - to your code! - oddebug.h .............. Interface definitions of the debug module. - usbportability.h ....... Header with compiler-dependent stuff. - usbdrvasm.asm .......... Compatibility stub for IAR-C-compiler. Use this - module instead of usbdrvasm.S when you assembler - with IAR's tools. - License.txt ............ Open Source license for this driver. - CommercialLicense.txt .. Optional commercial license for this driver. - USB-ID-FAQ.txt ......... General infos about USB Product- and Vendor-IDs. - USB-IDs-for-free.txt ... List and terms of use for free shared PIDs. - -(*) ... These files should be linked to your project. - - -CPU CORE CLOCK FREQUENCY -======================== -We supply assembler modules for clock frequencies of 12 MHz, 12.8 MHz, 15 MHz, -16 MHz, 16.5 MHz 18 MHz and 20 MHz. Other clock rates are not supported. The -actual clock rate must be configured in usbconfig.h. - -12 MHz Clock -This is the traditional clock rate of V-USB because it's the lowest clock -rate where the timing constraints of the USB spec can be met. - -15 MHz Clock -Similar to 12 MHz, but some NOPs inserted. On the other hand, the higher clock -rate allows for some loops which make the resulting code size somewhat smaller -than the 12 MHz version. - -16 MHz Clock -This clock rate has been added for users of the Arduino board and other -ready-made boards which come with a fixed 16 MHz crystal. It's also an option -if you need the slightly higher clock rate for performance reasons. Since -16 MHz is not divisible by the USB low speed bit clock of 1.5 MHz, the code -is somewhat tricky and has to insert a leap cycle every third byte. - -12.8 MHz and 16.5 MHz Clock -The assembler modules for these clock rates differ from the other modules -because they have been built for an RC oscillator with only 1% precision. The -receiver code inserts leap cycles to compensate for clock deviations. 1% is -also the precision which can be achieved by calibrating the internal RC -oscillator of the AVR. Please note that only AVRs with internal 64 MHz PLL -oscillator can reach 16.5 MHz with the RC oscillator. This includes the very -popular ATTiny25, ATTiny45, ATTiny85 series as well as the ATTiny26. Almost -all AVRs can reach 12.8 MHz, although this is outside the specified range. - -See the EasyLogger example at http://www.obdev.at/vusb/easylogger.html for -code which calibrates the RC oscillator based on the USB frame clock. - -18 MHz Clock -This module is closer to the USB specification because it performs an on the -fly CRC check for incoming packets. Packets with invalid checksum are -discarded as required by the spec. If you also implement checks for data -PID toggling on application level (see option USB_CFG_CHECK_DATA_TOGGLING -in usbconfig.h for more info), this ensures data integrity. Due to the CRC -tables and alignment requirements, this code is bigger than modules for other -clock rates. To activate this module, you must define USB_CFG_CHECK_CRC to 1 -and USB_CFG_CLOCK_KHZ to 18000 in usbconfig.h. - -20 MHz Clock -This module is for people who won't do it with less than the maximum. Since -20 MHz is not divisible by the USB low speed bit clock of 1.5 MHz, the code -uses similar tricks as the 16 MHz module to insert leap cycles. - - -USB IDENTIFIERS -=============== -Every USB device needs a vendor- and a product-identifier (VID and PID). VIDs -are obtained from usb.org for a price of 1,500 USD. Once you have a VID, you -can assign PIDs at will. - -Since an entry level cost of 1,500 USD is too high for most small companies -and hobbyists, we provide some VID/PID pairs for free. See the file -USB-IDs-for-free.txt for details. - -Objective Development also has some license offerings which include product -IDs. See http://www.obdev.at/vusb/ for details. - - -DEVELOPMENT SYSTEM -================== -This driver has been developed and optimized for the GNU compiler version 3 -and 4. We recommend that you use the GNU compiler suite because it is freely -available. V-USB has also been ported to the IAR compiler and assembler. It -has been tested with IAR 4.10B/W32 and 4.12A/W32 on an ATmega8 with the -"small" and "tiny" memory model. Not every release is tested with IAR CC and -the driver may therefore fail to compile with IAR. Please note that gcc is -more efficient for usbdrv.c because this module has been deliberately -optimized for gcc. - -Gcc version 3 produces smaller code than version 4 due to new optimizing -capabilities which don't always improve things on 8 bit CPUs. The code size -generated by gcc 4 can be reduced with the compiler options --fno-move-loop-invariants, -fno-tree-scev-cprop and --fno-inline-small-functions in addition to -Os. On devices with more than -8k of flash memory, we also recommend the linker option --relax (written as --Wl,--relax for gcc) to convert absolute calls into relative where possible. - -For more information about optimizing options see: - - http://www.tty1.net/blog/2008-04-29-avr-gcc-optimisations_en.html - -These optimizations are good for gcc 4.x. Version 3.x of gcc does not support -most of these options and produces good code anyway. - - -USING V-USB FOR FREE -==================== -The AVR firmware driver is published under the GNU General Public License -Version 2 (GPL2) and the GNU General Public License Version 3 (GPL3). It is -your choice whether you apply the terms of version 2 or version 3. - -If you decide for the free GPL2 or GPL3, we STRONGLY ENCOURAGE you to do the -following things IN ADDITION to the obligations from the GPL: - -(1) Publish your entire project on a web site and drop us a note with the URL. -Use the form at http://www.obdev.at/vusb/feedback.html for your submission. -If you don't have a web site, you can publish the project in obdev's -documentation wiki at -http://www.obdev.at/goto.php?t=vusb-wiki&p=hosted-projects. - -(2) Adhere to minimum publication standards. Please include AT LEAST: - - a circuit diagram in PDF, PNG or GIF format - - full source code for the host software - - a Readme.txt file in ASCII format which describes the purpose of the - project and what can be found in which directories and which files - - a reference to http://www.obdev.at/vusb/ - -(3) If you improve the driver firmware itself, please give us a free license -to your modifications for our commercial license offerings. - - -COMMERCIAL LICENSES FOR V-USB -============================= -If you don't want to publish your source code under the terms of the GPL, -you can simply pay money for V-USB. As an additional benefit you get -USB PIDs for free, reserved exclusively to you. See the file -"CommercialLicense.txt" for details. - |