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Optiboot / optiboot

Small and Fast Bootloader for Arduino and other Atmel AVR chips
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avrdude has EEPROM bug #235

Open WestfW opened 6 years ago

WestfW commented 6 years ago

Optiboot is about to be tuned enough to include EEPROM support in a 512byte image. That's swell, but it turns out that AVRDUDE is somewhat inconsistent WRT reading and writing EEPROM - some parts (ATmega328x, for example) use a word-based address in the STK_LOAD_ADDRESS command, and other parts (notably ATmega8) ) used a byte-based address. This is documented here: https://savannah.nongnu.org/bugs/?48131

There's probably an avrdude.conf based patch, but the short-term issue is that an ATmega8 with optiboot will not interact properly with AVRDUDE. (It doesn't work with ArduinoISP, either!)

Documented here for the sake of completeness.

MCUdude commented 6 years ago

So, about getting EEPROM support in a 512B image; how can this be done? I just compared "my" repo to yours in terms of compiled size. Both are compiled with avr-gcc 5.4.0.

make atmega328 LED=B5 LED_START_FLASHES=2 UART=0 AVR_FREQ=20000000L BAUD_RATE=500000 BIGBOOT=1

"My optiboot_flash repo":

  avr-size atmega328/20000000L/optiboot_flash_atmega328_UART0_500000_20000000L.elf
   text    data     bss     dec     hex filename
    560       0       0     560     230 atmega328/20000000L/optiboot_flash_atmega328_UART0_500000_20000000L.elf

Official Optiboot repo:

avr-size optiboot_atmega328.elf
   text    data     bss     dec     hex filename
    570     156       0     726     2d6 optiboot_atmega328.elf

If i've understood it correctly the text field is the actual size of the image in bytes. How can this be reduced to 512 or less?

MCUdude commented 6 years ago

ON TOPIC: I'm no avrdude.conf guru, so maybe you know where the EEPROM related bug for ATmega8 (or other devices with byte-based addresses) is located? My Arduino cores includes a separate copy of avrdude.conf, so a patch should be easy to roll out to affected users if we can figure how we can fix the bug.

WestfW commented 3 years ago

The trick to getting EEPROM support is that you don't get DOSPM support at the same time :-( (tough decision! Sigh.)

 make atmega328 LED_START_FLASHES=0 NO_APP_SPM=1 SUPPORT_EEPROM=1 LED_START_ON=1
avr-gcc (AVR_8_bit_GNU_Toolchain_3.6.1_495) 5.4.0
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

BAUD RATE CHECK: Desired: 115200, Real: 117647, UBRRL = 16, Difference=2.1%
avr-gcc -g -Wall -Os -fno-split-wide-types -mrelax -mmcu=atmega328p -DF_CPU=16000000L  -DBAUD_RATE=115200 -DLED_START_FLASHES=0      -DSUPPORT_EEPROM -DLED_START_ON=1 -DAPP_NOSPM=1         -c -o optiboot.o optiboot.c
optiboot.c:425:2: warning: #warning BAUD_RATE off by greater than 2% [-Wcpp]
avr-gcc -g -Wall -Os -fno-split-wide-types -mrelax -mmcu=atmega328p -DF_CPU=16000000L  -DBAUD_RATE=115200 -DLED_START_FLASHES=0      -DSUPPORT_EEPROM -DLED_START_ON=1 -DAPP_NOSPM=1       -Wl,-Tlinkscript.ld -Wl,--relax -nostartfiles -o optiboot_atmega328.elf optiboot.o 
avr-size optiboot_atmega328.elf
   text    data     bss     dec     hex filename
    510       0       0     510     1fe optiboot_atmega328.elf
avr-objcopy -j .text -j .data -j .version --set-section-flags .version=alloc,load -O ihex optiboot_atmega328.elf optiboot_atmega328.hex
MCUdude commented 3 years ago

I favored so_spm because EEPROM upload is not currently supported in Arduino IDE, and you can do cool and useful things with do_spm.

I created a high-ish level Flash library to make the internal flash memory more accessible to the end-user: https://github.com/MCUdude/MiniCore/tree/master/avr/libraries/Optiboot_flasher

WestfW commented 2 years ago

See the conclusion at https://github.com/avrdudes/avrdude/issues/967#issuecomment-1188432577 and related discussion. TLDR: a bug was introduced in AVRDUDE back in 2006, and since then other code (like optiboot and Arduino as ISP) has compensated, assuming that the buggy code was intentional.)

mcuee commented 2 years ago

For classic AVRs, this has been fixed in avrdude git main by the following PR.

It does introduce regression for optiboot_x and optoboot_dx. This will be fixed in the following PR.

mcuee commented 2 years ago

There may still be some issues with four chips (ATmega161 ATmega163 ATmega8515 ATmega8535) and there is a potential fix here.

mcuee commented 1 year ago

From avrdude side, this issue has been fixed in avrdude git main, which will lead to avrdude 7.1 release soon.

mcuee commented 1 year ago

From Optiboot side, #357 is a real issue related to EEPROM.

mcuee commented 1 year ago

urboot (which is indeed inspired by Optiboot) does achieve this goal within 512B. https://github.com/stefanrueger/urboot

Tight code: most bootloaders fit into

mirh commented 1 year ago

Didn't the guy at https://github.com/Optiboot/optiboot/issues/227 (most updated version here I think?) already handle EEPROM+SPM?