The Optiboot version 8 has a do_spm function which can be called from application. The Optiboot repository contains an example for the use of this function.
SPM is the AVR CPU instruction to write to flash memory. The Optiboot wraps this in a function. A pointer to this function is put in a 'vector table' at the beginning of the bootloader. The first pointer ...
It's enforcing this line from the arduino:avr boards.txt
To be clear, the board is assumed to have a bootloader, even if you're not using it to get the code onto the board, that is upload via programmer.
You could edit that and change some fuses yourself. But you could also probably just use MCUdude ...
The ATMega328P datasheet has the following table in it:
The top 5 bits of the of the Extended Fuse Byte are default 1 and are reserved. You're not really supposed to change them, since they might be used in the future for a 328P-like part and setting them to something other than 1 could have unexpected results. In the 328PB variant bit number 3 is used ...
Theoretically it is quiet easy to fake that double-tap with software, but there might be some obstacles in practice.
The bootloader uses an unsigned long value in RAM memory to indicate if the double tap happend. The actual bootloader for the zero uses the following definitions.
// zero specific; but other boards use the same values AFAIK
// (in ...
It seems that you are using a lm317 voltage regulator to power your atmega328p MCU but I think you forgot the part that lm317 needs feedback of 1.25v with voltage divider network to set its variable output voltage in the schematic you have connected adj pin of lm317 directly to GND.
S0 check your output vtg from your regulator and another issue voltage ...
I don't know the Sloeber toolset, but it seems very unlikely, that it really has overwritten the bootloader. When programming via USB, it is actually the bootloader, which writes the program into the flash memory. So that would mean, that the bootloader had overwritten itself, only because a too large program. Not sure, if this is even possible.
Anyway, you ...
Brownout detector was triggered
is being generated by your ESP32 because there is a problem with the Vcc power to the module.
Check the following:
Your USB cable. Some cables are just plain cheap and can't supply the power the ESP32 needs. Get a better one.
Some PCs are not able to supply enough power from their USB ports to supply the ...
The MCU on the Uno R3 comes with a specific bootloader (Optiboot) and
fuse configuration (external clock, clock prescaler disabled, bootloader
enabled...). You may find some ATmega328Ps on the market that have been
specifically configured as drop-in replacements for the one on an Uno.
Those should “just work”. If the ones you bought come with a different
Based on this:
Note: The Arduino UNO stopped responding when I mistakenly
short-circuited a connection, I mistakenly passed 12v to one of the
header pins of sensor shield mounted on the board.
There are no I/O pins on the Arduino that are 12V tolerant. You have almost certainly "fried" your Uno board. It's possible the only casualty is the ...
The values can be easy found for generic CH340g and ATmega2560 implementations:
C1,C2 = 100nF, C3,C4 = 22pf but depends on the crystal you use, all others excepting C12 are decoupling capacitors.
C12 has no sense where it's placed, it seems that the schematic is a bad combination of schematics, this capacitor should reset the board at power on but it breaks ...
Well after "working" on this all day, it turns out that the solution was to use the "Arduino as an ISP" solution as described on the arduino.cc website.
Why the USB-ISP solution did not work is not immediately obvious as I have used it successfully before - just not with this board!
FWIW, the blinking sequence I observed when burning the ...
Yay! - I now have a fully working Nano with new bootloader and application loaded usinenter code hereg this.
I have done so much that I'm not sure what the original problem was but the final change was modifying the "programmers.txt" file such that "Arduino as ISP" entry was changed as follows;
After poking around in the git repository for a while, I've solved the problem. To work with these new TinyAVR-0/1 microcontrollers, a new version of avrdude is needed. Since avrdude hasn't made a stable release yet, it's necessary to build a new avrdude from source from SVN.
$ svn co https://svn.savannah.nongnu.org/svn/avrdude/trunk avrdude
$ cd avrdude/...
This is something that is far far easier to measure than to try and calculate.
Here's an Arduino Uno R2 with a simple sketch that just turns on D2. Green is the power (7V to the barrel jack) and yellow is D2.
As you can see it takes 1.544 seconds (according to the resolution of my oscilloscope which, over those time scales, isn't that great) before D2 is ...
If you have a sketch which can write its updated version into EEPROM of ATmega328p and then boootload from the EEPROM, then you can use the flash for the same purpose. The ATmega328p has 32kB of flash and only 1kB EEPROM.
For my ArduinoOTA library I developed a way to store the uploaded binary in upper half of the flash and then let the bootloader copy the ...
Your RESET circuit is wrong.
You have no pullup resistor on the RESET pin of the ATMega3560.
You have an extraneous pulldown resistor on the D7 pin of the 16U2.
That means your 16U2 will not be able to trigger a reset of the ATMega2560 to run the bootloader.
Remove the pulldown on D7 of the 16U2 and add a 10kΩ pullup to the RESET pin of the ATMega2560. ...
Maybe you could jump to right after the line
if (!(ch & _BV(EXTRF))) appStart();
Here is an excerpt of the disassembly:
if (!(ch & _BV(EXTRF))) appStart();
7e06: 81 ff sbrs r24, 1
7e08: f0 d0 rcall .+480 ; 0x7fea <appStart>
#if LED_START_FLASHES > 0
// Set up Timer 1 for timeout counter
The source of Optiboot on Uno is here.
I would prefer a simple watchdog reset with
But I am not sure now if it runs sketch upload detection in bootloader.
For direct jump to Optiboot on Uno (one flash page) this should work
typedef void (*bootloader_jump_t)();
const bootloader_jump_t bootloader_jump = (...
This isn't the exact answer but it helps.
Uploading without avrdude is complicated and generally slow. The best solution to not using the IDE is to open and close a port then use the avrdude command that the ide usually uses.
from serial import Serial
from time import sleep
from subprocess import run
while input('Press enter to upload ') == '':
It sounds like you have a newer board than the version of Micronucleus in the Arduino package.
As I discovered here you basically need to upgrade micronucleus in your Ardino installation, which you can download from here
Download the zip file from Github and extract it. Then in a terminal (if you're not already in one) go to the directory you extracted.
The Arduino 'device' is identified by the USB device code of the USB to TTL Serial on Arduino or by core code in case of MCU with native USB. The USB ids are written to the USB chip in factory or are part of the firmware/core and they are listed in boards.txt file so that the IDE then knows what Arduino is attached. If you use a common FTDI it doesn't have ...