====================================================== ATMEL AVR UART Bootloader for AVR-GCC/avr-libc based on the AVR Butterfly bootloader code by Martin Thomas, Kaiserslautern, Germany mthomas@rhrk.uni-kl.de eversmith@heizung-thomas.de http://www.siwawi.arubi.uni-kl.de/avr_projects Addtional code and improvements provided by Uwe Bonnes, Bjoern Riemer and Olaf Rempel. ====================================================== Programming-Software (on the "PC-Side"): * AVRProg (included in AVRStudio) available at www.atmel.com. MS-Windows only. AVRProg can be used as stand-alone application. (avrprog.exe) * avrdude available at http://savannah.nongnu.org/projects/avrdude/ "Multiplattform" 21. May. 2006 - Version 0.8beta Version contributed by Olaf Rempel. He has done a lot of modifications. -> "cleaner code", smaller binaries. 09. Feb. 2006 - Version 0.75 * additional STARTUP_WAIT support contributed by Bjoern Riemer 18. Aug. 2005 - Version 0.74 * AT90CAN128 support contributed by Uwe Bonnes * Makefile modifications contributed by Uwe Bonnes 23. Feb. 2005 - Version 0.7 * (Version 0.6 has never been available on the web-page) * ATmega128 support * code cleanup * Tested with ATmega8, ATmega32 and ATmega128 7. Apr. 2004 - Version 0.5 * added different startup-methods * compatible with ATmega8 now * included makefile adopted to ATmega8 now (ATmega16 options still available) * fixed jump to application which did not work reliably before * tested with ATmega8 * minimal options and startup-code result in bootloader-size < 512 words 6. Apr. 2004 - Version 0.4 * Buffered read of chars from UART during programming since eeprom-write is too slow for unbuffered operation. So EEPROM-upload does work now. * Added BOOTICE-mode to flash JTAGICE-compatible hardware (ATmega16@7,3Mhz) (if you know about BOOTICE, you may unterstand why this has been added, if not just keep the option disabled) * small changes in (my)boot.h (lock-bit-mask) found out during the development of the STK-500-compatible bootloader. But setting lock-bits still does not work with this bootloader. * read of the low-fuse byte works (high byte still TODO) * read of the lock-byte works (write still TODO) 27. Mar 2004 - Version 0.3 Felt that as much functions from avr-libc's boot.h as possible should be used without modifications. Latest CVS-version of boot.h is included. Only the read-routine is still "self-made" based on ATMELs assembler-code. EEPROM write on Mega16 does not work (and did not work with V0.2 too). May be caused by my old Mega16 chip. Needs testing. Flash read/write and EEPROM read works. Still only tested with ATmega16. This version may not work with the ATmega169 any more. 24. Mar 2004 - Version 0.2 During the development of a data-logger application with the AVR-Butterfly there was a need to make some changes in the bootloader. The same problem again: no IAR compiler. The same way to solve the problem: a port of the code to avr-gcc/avr-libc. So this code is based on the ATMEL Butterfly bootloader source code Rev 0.2 for IAR. The bootloader-port for the Butterfly which mimics the complete functionality of the original BF-bootloader is availabe at: www.siwawi.arubi.uni-kl.de/avr_projects Atmel used a separate "lib" written in "pure" assembly to access the low-level functions for flash read/write. Well, so far I don't know how to use "mixed language sources" with the avr-gcc toolchain, so the low-level routines have been implemented as inline assembler. The avr-libc boot.h module written by Eric Weddington served as a template Three of the four low-level routines found in lowlevel.c come from boot.h with minimal changes. The read routine has been developed based on the ATMEL assembler code. Ignore the fuse and lock-bit readout. Read and Set is not enabled (TODO). --------------- Installation ----------------- - Change the MCU type in the makefile (so far ATmega16 has been tested, ATmega169, ATmega8 and ATmega32 should be o.k. too. - Change the boot(loader)-size in Makefile, this bootloader is larger than 512 words (1024 bytes), so select at least _B1024! - Change the XTAL in Makefile to the clock-frequency of your board (keep BAUDRATE at 19200). See the datasheet for frequencies with minimum error at 19200bps and select Crystal/Oscillator to get minimum errors. - Change the start-condition in Makefile. Default is: enter bootloader if Pin A7 is connected to GND during reset/startup - Please use at least avr-gcc 3.3.1/avr-libc 1.0 or WINAVR Sept. 2003 or later to compile and link the bootloader. - upload the hex-File to the AVR (STK500, STK200, SP12 etc.) - program the "Boot Flash section size" (BOOTSZ fuses) according to the boot-size selected in main.c i.e. BOOTSZ=00 for boot-size 1024 words on ATmega16 - enable the BOOT Reset Vector (BOOTTRST=0) - Set the lock bits to protect the bootloader from SPM-writes (Boot Loader Protection Mode 2 in STK500- plugin) - Connect the AVR UART Pins via level-shifter/inverter (i.e. MAX232) to you PCs Com-Port. - Reset the AVR while fullfilling the bootloader start- condition. Which means connect PA7 to GND in the default config during reste/power-cycle. Keep the connection or hold the key down until you see the AVRPROG dialog! - Start AVRPROG (AVRStuido/Tools or stand-alone) - keep PA7 grounded! (avrdude is supported too, check the avrdude manual for command-line options). - AVRPROG will detect the bootloader, you may release PA7 now - see AVRStuido online-help for more information how to use AVRPROG - make sure to EXIT from AVRPROG (button) to start your main-application (or toogle power/reset) good luck, feedback welcome. Martin