There three ways to accomplish this. (last is my favorite)
1) Jumper an unused IO to the RESET pin. Leave it as INPUT for normal
run, As it is externally pulled high. And when desired to reset set
it as LOW and Output. (bang its rebooting).
pinMode(PINtoRESET, INPUT); // Just to be clear, as default is INPUT. Not really needed.
It can be done with one button, one resistor, one capacitor and one GPIO pin (in addition to the RESET pin):
simulate this circuit – Schematic created using CircuitLab
Pressing the button causes a LOW pulse on the RESET pin (in the exact same way as the USB interface does).
During your startup procedure you read the GPIO pin you have chosen. If it's ...
Atmel specifically recommend against driving /RESET low from an output pin, because the first thing that the reset process does is set all pins to high impedance, thus cancelling the reset pulse before the recommended reset pulse length has elapsed.
The recommended use of the watchdog timer does not suffer from these limitations. It is designed to reset the ...
The reset button does pretty much the same as unplugging the board and plugging it back in. It restarts your program from the beginning.
The same thing happens when you program the board - the USB interface presses the reset button for you. That then enters the bootloader for a second or two so it can try and program it.
When you reset the board the ...
If you just want the reset button to change the program mode, the
simplest thing would be to let the button reset the Arduino and switch
modes each time your program restarts. Then you do not need to change
the fuses or get a high voltage programmer. The code would look like
// At startup, switch to the next mode.
if (++mode >...
Here is the circuit I use which depends on a heartbeat from the arduino and resets the arduino if 8 pulses are missed and also enables the arduino code to know that an external watchdog reset occured
and the Arduino code which can be incorporated into your sketch
#define ResetDetect 8 // watchdog detect pin, HIGH if a watchdog reset has ...
The following 555 circuit will produce a 170 ms low-going pulse every 24.2 hours. You can adjust the values of the components using this calculator if you want different timing parameters.
Since the reset line of a microcontroller is configured for open-drain (meaning you can connect several inputs to it, which is a good thing since we are taking advantage ...
One of the most obvious issues here is that you are enabling the watchdog timer with a delay of 1S and then you are asking the micro controller to sleep for 2S, printing something and then going back into the loop. This, in theory, should be fine(your wdt should trigger a reboot during the 2 second wait) but I've seen it cause issues.
Additionally some ...
If you review the Uno schematic, you can see the circuitry that enables an automatic reset when serial communication starts. The circuitry is intended to allow easy program downloading.
There are two or three ways to prevent that reset: add a 10 μF capacitor from ground to reset; use a much-lower resistance for the pullup on reset; cut a trace from the ...
It's happening because you're not giving the ESP8266 a chance to do its housekeeping activities and the watchdog (which is enabled by default) is timing out - as evidenced by the very first line of your output:
Soft WDT reset
You need to allow the MCU to do other things at the same time as you are printing to serial:
for(unsigned int i =...
That's the firmware waiting for a programming connection. If you want alternate behavior them burn SparkFun's ATmega32U4 firmware to it. One press of Reset will reset the device, and two presses will put it into programming mode.
Every time you rewrite an Arduino, the previous code is completely wiped out (except for the bootloader, which doesn't change).
You will not fill up your arduino -- it is not like a filesystem where you are continually adding new files. Each new programming/upload overwrites all the existing code.
Uploading a blank sketch is the genuine way to "erase" an ...
There is no power spike or loss to the PCB. The car is not actually
running, I am just turning the key on and off.
And did you verify that with a digital scope? I doubt it.
I don't think you understand how ugly the electrical system in a car really is. If there is a coil or relay switched then there will be spikes. Do some research on electronics for ...
While it looks interesting as idea, IHMO you have keep in mind:
Include some code for button denouncing logic. Actually you will receive couple of “resets” during ~20ms during button press. Without denouncing you may end up with reset signal right at the moment you write to the EPROM. While EPROMs are pretty “solid” nowadays, it many not be good practice. ...
You can reset the Uno over the serial link by toggling the DTR line. How you do that depends on what platform and language you are using. There is a capacitor between the line and the reset pin, so the toggle must last a minimum ammount of time. 0.5 seconds works.
This is ok for just a quick fix hack, but probably better in the long run to (1) figure out ...
Why does that happen?
When the serial port is opened by either monitor, avrdude or other it toggles the DTR pin of the serial port. Which in turn is AC coupled through C4 100nF. This toggling is converted to a up and down pulse on the ATmega(CPU)'s RESET pin. The subsequent reset starts initially with the boot loader, which typically in turn waits for a ...
If your pro micro does not have a reset button, wire one between reset and ground.
Press reset twice, quickly, and immediately hit upload on the IDE.
Secondly, make sure you've downloaded and installed the Sparkfun board files for the pro micro.
ok guys - found the answer: this post here at electronics-stackexchange gave the right hint: Watch-Dog Timer. And my gut feeling was right as well - i simply use a NPN-Mosfet that is being triggered by an Arduino-PIN (which easily can be done while sleeping as well as sleeping means waking up every 8seconds anyway) that connects the capacitor to ground and ...
You can't. There is no way of detecting if the serial monitor is open or not.
However, you can disable the automatic reset and provide some functionality in your code for saving data to EEPROM when prompted through a command entered on the serial monitor (if you now need to even save the data).
The first thing that happens when you apply power to a board or press reset, is the bootloader executes. That waits for a short time to accept a new sketch over the serial port. If nothing arrives it terminates and executes the existing sketch.
On the Uno that delay is only 2 seconds. However on the Leonardo the delay is much longer (around 5-8 seconds) ...
What you have done is to disable the "HUPCL" signal that is sent when the port is opened/closed.
You can turn the signal back on with:
$ stty -F /dev/ttyACM3 hupcl
And you can turn it off again with:
$ stty -F /dev/ttyACM3 -hupcl
HUPCL means "HangUP on CLose".
Yes, it is possible. See the documentation on memory
sections, from the avr-libc manual. For example:
// Run this after initializing the stack pointer and zero_reg, but
// before initializing the RAM.
void __attribute__((naked, used, section(".init3"))) magic(void)
Note that this runs after both a warm reset and a cold boot. See
1/0 is an exception (divide by zero). esp8266 arduino core has soft reset: ESP.reset(). Calling this function you get a valid reset.
Note to software reset. esp8266 has a bug. If software reset (or exception) is executed in program started right after the flashing, the board goes back to flashing mode because the flashing flag is still active. Perhaps you ...
The garbage is because the ESP8266 outputs boot information at 76800. This should include the boot reason and may help you understand why the code's not working as expected.
Try changing your Serial speed to 76800 in your code (just so that your messages don't end up being gibberish), use 76800 on platformio's monitor and you should be able to at least see ...
The reset is basically jumping to the reset vector address 0x0000 (if you don't have the bootloader, or you don't want to start it).
There is also the MCUSR register, indicating which reset source caused the reset. It won't be set if you do simple jump to the reset adress.
The memory is also preserved, but C/C++ init code takes place and initialize your ...
No. There is no way you can use it (or not without a lot of messing around...).
According to the ESP8266 GPIO Reference Guide:
GPIO6 to GPIO11 are usually connected to the flash chip in ESP8266 boards. So, these pins are not recommended to use.
If you mess with those pins you won't be able to access the flash chip - and that means that you can't run ...
It does it to "force" a reset.
Historically, when you open the serial port on an FTDI interface, the DTR will automatically go LOW. However, recently FTDI decided it'd be a good idea to change their driver so that when you open the port the DTR line doesn't go low - you have to manually tell it to go low. But this is only on the FTDI official drivers.