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Questions tagged [watchdog]

An independent timer module usually incorporated into the same chip as a uProcessor which resets the processor after a certain length of time. The idea is that during usual operation the code running should always be able to reset the watchdog timer before the watchdog resets the processor. If the processor gets into a bad state or the code is corrupted it will not reset the watchdog and in turn will be reset back to normal operation.

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34
votes
1answer
7k views

Why does my AVR reset when I call wdt_disable() to try to turn the watchdog timer off?

I am having a problem where executing a disable watchdog sequence on an AVR ATtiny84A is actually resetting the chip even though the timer should have plenty of time left on it. This happens ...
19
votes
7answers
3k views

Necessity of an external watchdog timer

What is the need for an external watchdog timer for a microcontroller? Most of the microcontrollers are designed with an internal watchdog timer. However, in some of the circuits they are using an ...
17
votes
3answers
19k views

Use AVR Watchdog like normal ISR

I'm trying to wrap my head around the watchdog timer on the ATTinyX5 series. So things I've read made it seem like you could use it for making the program do something specific ever N seconds but ...
15
votes
5answers
27k views

Independent watchdog (IWDG) or Window watchdog (WWDG)?

I'm still searching to find an answer for this question: Why while the stm32 MCUs have a perfect watchdog (I mean Window watchdog (WWDG)), there is a simple watchdog (Independent watchdog (IWDG)) ? ...
8
votes
3answers
2k views

Which of these approaches for a watchdog timer?

I recently learned about watchdog timers, and am trying to implement one for my circuit for the purpose of resetting my (AVR) microcontroller if it hangs (i.e., doesn't respond to the watchdog). ...
7
votes
2answers
686 views

Microcontroller's watchdog

Can anyone explain a little more about watchdogs, specifically in the circuitry level? If there is some kind of problem in the chip, how can I guarantee that it will be kept running? It is ...
6
votes
3answers
3k views

ARM watchdog reset

I have an MP3 development board I picked up from sparkfun that runs off the LPC2148 ARM processor. In looking through the code, I see a function to force a watchdog reset. My question is, how do you ...
6
votes
2answers
2k views

Low power, cheap, long timeout, watchdog circuit

I need a circuit to act as a watchdog to a micro (which is not powered (instead of in a sleep mode)most of the time). it needs to be low power (< ~4uA) and non-programmable. So no I2C RTCs or MCUs....
5
votes
2answers
4k views

Windowed watchdog timer

Can someone please explain how windowed watchdog timer is different from the normal watchdog timer? When is windowed watchdog timer prefferred over normal watchdog timer?
5
votes
2answers
3k views

Does the internal 8Mhz oscillator in an ATTINY run even if no clocks are connected to it?

If I set up the fuses on an ATTINY so that the system clock uses the internal 128Khz oscillator (sometimes called the "Watchdog oscillator"), does the internal 8Mhz oscillator still run? It does not ...
5
votes
4answers
518 views

How often do AVR's actually glitch and need a watch-dog reset in the real-world?

Have you ever seen an otherwise happy AVR spontaneously glitch and require a reset? Assuming: a nice stead power supply that stays inside the specified range a correctly sized decoupling cap ...
4
votes
2answers
4k views

Arduino w/ Atmega328: can't clear the watchdog

I'm using the onboard software watchdog facility of an Atmega328 like documented here. My purpose is to limit to 2 seconds the execution of a portion of code that could lead to endless computation. ...
4
votes
2answers
2k views

How to debug reset caused by WDTCTL security key violation in MSP430F1611?

I'm working on a sensor project which uses TelosB based on MSP430F1611 running TinyOS. My program is reset some time after boot up. After the PUC reset, IFG1 is found with WDTIFG bit set, indicating ...
4
votes
2answers
158 views

Low power strategy for dealing with spontainious bit flips durring sleep on AVR 8-bit?

I am designing a ATTINY-based circuit that is intended to run unattended for very long periods of time on a very small battery. The device spends almost all of its time in deep sleep, and only wakes ...
4
votes
2answers
2k views

STM32F4: WWDG interrupt fires as soon as it's enabled

I'm doing some coding on an STM32F411 board, used the CubeMX & HAL Libraries for laziness. I'm trying to get the windowed watchdog (WWDG) up & running, and doing the very basic version (non ...
3
votes
3answers
385 views

Effective use of output signal of a watchdog timer

Subsequent to my previous question regarding watchdog timers, I am interested in deciding the RESULT of such a watchdog: Assume I add a generic external watchdog timer to my circuit. If not toggled ...
3
votes
3answers
2k views

74123 vs 4538 as watchdog timer

I want to use a retriggerable monostable multivibrator as a hardware watchdog. This is for an amateur satellite project so I need to use basic rad hard logic chips (as opposed to more sophisticated ...
3
votes
2answers
2k views

Watchdog timer issue - AVR ATmega324PA

I was using ATmega32A before and now I am migrating to ATmega324PA just to enhance power management. Now I am testing the new controller in every aspect. This is a simple code to check the watchdog ...
3
votes
1answer
691 views

How do I wake from sleep on PIC10F200 via watchdog?

So far I have worked with many other micro controllers but not the PIC-family. I'm having trouble with waking from sleep via watchdog on a PIC10F200. I'm programming it in C using the MPLAB X IDE v2....
3
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2answers
2k views

Watchdog reset using C32 v2.00 compiler

Compiling an existing PIC32 project using the v2.00 C compiler produces a continual watchdog reset. This problem does not appear using the previous v1.12 compiler. Changing the watchdog postscaler ...
3
votes
2answers
192 views

Extend the time delay of an asserted WDT active low

I am new to electronics and would appreciate any help. I am trying to design a watchdog timer circuit using the TI WDT (mfg part # TPS3813K33DBVT). I am using it to reset an Arduino (I wish to use an ...
3
votes
1answer
4k views

How do I avoid a reset when using the watchdog in interrupt mode and changing the timeout?

I'm writing a program for an ATtiny85. I want to use the watchdog to wake up from power down in certain intervals. It all works fine as long as the intervals for a watch dog event don't change within ...
3
votes
3answers
777 views

How to test a CPU watchdog on board?

The watchdog of an ATMEL ATXMega128 should have been enabled with fuses. It triggers a reset, if the timer was not reset within the configured time span. I want to be sure, that it is enabled and ...
3
votes
1answer
631 views

Why am I receiving a Modem Status (0x8A) on broadcast messages (XBee)?

I am sending a Remote AT Command Request in broadcast (without ACK - frameID = 0x00), from my Coordinator API, to set the CB command to 1: this simulate 1 commissioning button press in software of the ...
2
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2answers
213 views

Reporting crashes/resets in Embedded Systems(8 bit)

I'm using PIC controllers, and I have used watch dog timers to trigger a reset in case of the s/w gets stuck somewhere, and also to support in case of severe hardware crashes. I think that resetting ...
2
votes
2answers
466 views

Watchdog Signature in Flash memory or RAM?

We used to use Watchdog signatures in our control applications. Basically we used to allocate a reserved memory in RAM(uninitialized) and used to store the watchdog signatures. On power on, the ...
2
votes
1answer
707 views

Fail to verify if watch dog timer works properly

I wrote a simple watch dog timer program. First I light up a LED, and I want to see if watch dog timer will reset the chip and the LED would be turned off(I didn't feed the watch dog). ...
2
votes
1answer
73 views

Way to reset an MCU when it's GPIO output becomes constant HIGH or LOW instead of a low frequency PWM

In one of our projects, we are observing MCU hanging up supposedly due to EFT. WDT is not helping. The only way to get the device into working condition is to reset the MCU by reset pin or power cycle....
2
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1answer
593 views

Atmega328P Watch Dog Timer - Delay Issue

I am trying to give delay of 0.5 seconds on 13 pin of the arduino using Watch Dog timer interrupt, the code complies and works fine but the led is blinking so rapidly that it seems like it is ...
2
votes
1answer
2k views

Understanding PIC32 watchdog timer operation

I'm new to uC development and have been fooling around with the PIC series for about 6 months now. I recently started working with the PIC32 and Microchip's XC32 C++ compiler. I don't know if I have a ...
2
votes
1answer
1k views

what is logic contention when using a voltage supervisor?

I am using a voltage supervisor from MAXIAM (MAX6734A).I am confused about design notes in page 11. so,what is logic contention? the uP that I want to monitor is STM32F103ZET6.I read its datasheet:...
2
votes
1answer
2k views

PIC32 sleep mode with watchdog wakeup failing

I am in the process of trying to get a PIC32MX795F512L to run with lower power consumption. I'm trying to get it to enter sleep mode and then be woken by the watchdog timer. All pretty standard ...
2
votes
1answer
56 views

Preventing inadvertent feeding of an external watchdog

Most internal watchdog timers found on microcontrollers contain mechanisms to prevent an inadvertent feed, usually requiring the write of a specific key-value to the feed register, although some ...
1
vote
4answers
712 views

Read AVR watchdog timer

AVR Watchdog timers. Is there any way to read the watchdog timer from within the code? Intended use case: To get an approximate idea (very rough, +/- 1sec) of how long it has been since the ...
1
vote
3answers
586 views

Detect a missing PWM signal in the smallest possible board space

I have a motor control board that basically has zero space left, and the customer wants to add a fault flag to tell if their 2 kHz PWM input signal is lost. So basically, I need to detect a lack of ...
1
vote
3answers
725 views

External watchdog reset for AVR required

I had a circuit with ATmega644PA and use internal watchdog timer to bring the controller from a hang state to known by a reset. but my code still hangs in some loop ...
1
vote
1answer
320 views

Choosing values of resistive divider, versus pullup resistor value

I have a slight Catch-22 with my circuit portion shown below. The ADM6320 is, among other things, an undervoltage detector with factory threshold of 2.93 V (thus Reset output pin toggles when VCC <...
1
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2answers
748 views

AC Watchdog Circuit

I've designed a small AC-based watchdog circuit for my Raspberry Pi (schematic below). A buddy of mine looked at it and said that it was complicated, and there might be problems with asymmetric ...
1
vote
2answers
826 views

Correct ways for implementing standard inbuilt watch dog timers

I'm bit new with using applications that use watch dog timers and i'm up to use one for the first time. I'm using pic18f26j50 and it got an internal watch dog timer which got a limit from 2ms and can ...
1
vote
1answer
62 views

What's the name of a timeout relay which won't re-trigger if it times out?

I would like to replace the relay which triggers a water pump, with a relay which times out after, say, 10 minutes. And if it times out, it stays locked out until reset. Needs to be 230v AC on both ...
1
vote
2answers
5k views

How to stop/reset the watchdog timer from low-power sleep mode on an STM32L0C8?

On an STM32L0C8 MCU, I have the watchdog enabled while executing. At certain points in execution, I would like the chip to go into low power sleep mode. When it goes into low-power sleep mode though, ...
1
vote
2answers
566 views

Is it possible to implement a fail-proof watchdog timer in software?

I want to add a piece of code for watchdog timer within my source code so that the board resets automatically when programs hangs. I am using Mediatek Linkit One board.
1
vote
1answer
1k views

Watchdog timer not being called in sleep mode

On an ATMega328p, I'm trying to setup a program that counts 1 second intervals via the watchdog timer, even when the chip is in sleep mode. A button interrupt puts the chip into sleep mode. The ...
1
vote
2answers
1k views

How to use watchdog timer in ATmega128

I am working with an ATmega128 and need to reset the microcontroller after some 10 seconds has passed and the user has not interacted with microcontroller. As an example when the user has not pressed ...
1
vote
1answer
78 views

PIC16F884 keeps resetting even though WDT should be off

I just bought a PIC16F884 and put a simple C program on it using MPLAB: ...
1
vote
1answer
313 views

Watchdog to stop power supply

I want to stop supplying power for a short moment if a watchdog has not received a reset order for a while. Shutting down power is important as this is the only way for some buggy device to function ...
1
vote
2answers
264 views

Turning-off Watchdog Timer

Under severe power constraints I'm considering disabling the watchdog.The MCU is to work as a stepper motor controller in a watch and drive a simple bar display too. What can the consequences be? (...
1
vote
1answer
105 views

MSP430G2553 WDT ISR compilation error - GNU v4.9.1

I'm using GNU v4.9.1 compiler, and I'm just trying to work with WDT timer: void __attribute__((interrupt(WDT_VECTOR))) WDT_ISR(void) { P2OUT ^= BIT1; } When ...
1
vote
1answer
613 views

To get rid of useless redundancy--do I realy need a voltage supervisor?

I am using a voltage supervisor from MAXIAM(MAX7634A). It monitors VCC_3V3 and VCC_-3V3(I use LM358 to make it a positive one).Power supply distribution is shown below: VCC_3V3: stm32f103 EMP570T144 ...
1
vote
1answer
102 views

5V digital output to 24V

I'm sure it is a simple solution but I am new to this so please take it easy. I need to come up with something to convert a 5V digital output signal from a USB-1608G DAQ device with DIO to 24V ...