readme.txt

使用ATmage8制作的USB下载线

This is the README file for USBasp.

USBasp is a USB in-circuit programmer for Atmel AVR controllers. It simply
consists of an ATMega8 and a couple of passive components. The programmer
uses a firmware-only USB driver, no special USB controller is needed.

Features:
- Works under multiple platforms. Linux, Mac OS X and Windows are tested.
- No special controllers or smd components are needed.
- Programming speed is up to 5kBytes/sec.
- SCK option to support targets with low clock speed (< 1,5MHz).
- Planned: serial interface to target (e.g. for debugging).


LICENSE

The project is built with AVR USB driver by Objective Development, which is
published under a proprietary Open Source license. To conform with this
license, USBasp is distributed under the same license conditions. See the
file "firmware/usbdrv/License.txt" for details. 


LIMITATIONS

Hardware:
"circuit/usbasp_5V_circuit.pdf" shows a simple circuit. It doesn't meet the
voltage range on the data lines specified in USB 1.1. Also this circuit can
only be used for programming 5V target systems. For other systems a level
converter is needed.

Firmware:
The firmware dosn't support USB Suspend Mode. A bidirectional serial
interface to slave exists in hardware but the firmware doesn't support it yet.


USE PRECOMPILED VERSION

Firmware:
Flash "bin/firmware/usbasp.xxxx-xx-xx.hex" to the ATMega8 with a working
programmer (e.g. with avrdude, uisp, ...). Set jumper J2 to activate
USBasp firmware update function.
You have to change the fuse bits for external crystal, e.g. high byte = 0xc9
and low byte = 0x9f.

Windows:
Start Windows and connect USBasp to the system. When Windows asks for a
driver, choose "bin/win-driver". On Win2k and WinXP systems, Windows will
warn that the driver is is not 'digitally signed'. Ignore this message and
continue with the installation.
Now you can run the precompiled version of avrdude: change in command line
mode to "bin/win-avrdude" and start the program. Consult the documentation
of avrdude for details. Examples:
1. Enter terminal mode with an AT90S2313 connected to the programmer:
   avrdude -c usbasp -p at90s2313 -t
2. Write main.hex to the flash of an ATmega8:
   avrdude -c usbasp -p atmega8 -U flash:w:main.hex

Setting jumpers:
J1 Power target
   Supply target with 5V (USB voltage). Be careful with this option, the
   circuit isn't protected against short circuit!
J2 Jumper for firmware upgrade (not self-upgradable)
   Set this jumper for flashing the ATMega8 of USBasp with another working
   programmer.
J3 SCK option
   If the target clock is lower than 1,5 MHz, you have to set this jumper.
   Then SCK is scaled down from 375 kHz to about 8 kHz.


BUILDING AND INSTALLING FROM SOURCE CODE

Firmware:
To compile the firmware
1. install the GNU toolchain for AVR microcontrollers (avr-gcc, avr-libc),
2. change directory to firmware/
3. run "make"
4. flash "main.hex" to the ATMega8. E.g. with uisp or avrdude (check
the Makefile option "make avrdude"). To flash the firmware you have
to set jumper J2 and connect USBasp to a working programmer.
You have to change the fuse bits for external crystal, e.g. high byte = 0xc9
and low byte = 0x9f.

Software (avrdude):
An extension to avrdude (http://www.nongnu.org/avrdude/) was written.
To compile the software:
1. install libusb: http://libusb.sourceforge.net/
2. get the csv version of avrdude:
   export CVS_RSH="ssh"
   cvs -z3 -d:ext:[e-mail]:/cvsroot/avrdude co avrdude
3. cp usbasp/software/usbasp.* avrdude/
4. cd avrdude
5. apply the patch:
   patch < ../usbasp/software/avrdude_usbasp.xxxx-xx-xx.patch
6. configure to your environment:
   ./bootstrap (I had to comment out the two if-blocks which verify the
                installed versions of autoconf and automake)
   ./configure
7. compile and install it:
   make
   make install

Notes on Windows (Cygwin):
Download libusb-win32-device-bin-x.x.x.x.tar.gz from
http://libusb-win32.sourceforge.net/ and unpack it.
-> copy lib/gcc/libusb.a to lib-path
-> copy include/usb.h to include-path
cd avrdude
./configure LDFLAGS="-static" --enable-versioned-doc=no
make

Notes on Darwin/MacOS X:
after "./configure" I had to edit Makefile:
change "avrdude_CPPFLAGS" to "AM_CPPFLAGS"
(why is this needed only on mac? bug in configure.ac?)


FILES IN THE DISTRIBUTION

Readme.txt ...................... The file you are currently reading
firmware ........................ Source code of the controller firmware
firmware/usbdrv ................. AVR USB driver by Objective Development
firmware/usbdrv/License.txt ..... Public license for AVR USB driver and USBasp
software ........................ Source code of the host software
circuit ......................... Circuit diagram in PDF
bin ............................. Precompiled programs
bin/win-driver .................. Windows driver
bin/win-avrdude ................. avrdude compiled for Windows


MORE INFORMATION

For more information on USBasp and it's components please visit the
following URLs:

USBasp .......................... http://www.fischl.de/usbasp/

Firmware-only AVR USB driver .... http://www.obdev.at/products/avrusb/
avrdude ......................... http://www.nongnu.org/avrdude/
libusb .......................... http://libusb.sourceforge.net/
libusb-win32 .................... http://libusb-win32.sourceforge.net/


2005-07-03 Thomas Fischl <[e-mail]>
http://www.fischl.de