The reset line on a computer or other digital circuit places the circuit in a well defined initial state. Most microcontrollers have a built-in power-up reset to start the CPU executing code and may also have external resets and watchdog timers to help recover from unexpected events.

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55 views

Any way out of this Catch 22 on reset?

The problem is simple. I uploaded a buggy program using ST-Link to a stm32f303 prototype board. The bug was that the routine that kicks the watchdog in the power supervisor does not work. Therefore it ...
3
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1answer
87 views

Micro controller reset due to noise, PCB design for noise immunity

After making this PCB, I learnt the importance of ground plane. Besides ground plane, there is considerable amount of theory behind PCB designing which can provide immunity against ESD, surge, EMI, ...
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4answers
825 views

Arduino resetting/hanging due to sparks in ac line

This is the PCB design of the project I have been working on recently (my first pcb design). The idea is to control ac appliances (fans, bulbs etc) without relays. I am using triacs which are ...
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2answers
51 views

How does the Roland TR-909 reset circuit work

I'm troubleshooting my Roland TR-909 drum machine, which doesn't power on anymore. All of the voltages come up fine, but the reset line stays low. My suspicion is one or more of the components of the ...
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1answer
27 views

Controller Seems to be going into Undefined Exception on Reset

We have developed a board around STR912FAW47 Micro-Controller. During initial testing we tried to bring up the board by loading a simple program for toggling an output port pin. We are using ULINK2 ...
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2answers
59 views

Reset IC Buffer manually

I have a buffer which I want to reset. The EN pin is connected to a pull upp resistor while the Reset pin is connected to pull down resistor. What should I do to reset the buffer manually? Should i ...
-1
votes
2answers
53 views

Why is Reset Low True [duplicate]

What is the main reason that reset nets are low true? Is this so that any noise on the GND doesn't reset your system? If it was high true than couldn't you save the little leakage current that is ...
3
votes
1answer
54 views

PIC pin state change reset the PIC

I am trying to collect data from analog sensors (temperature and relative humidity) with a PIC microcontroller (PIC18F14K50). In order to save battery, the supply voltage of the sensors is turned ON ...
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1answer
91 views

Power on reset circuit for microcontrollers

In this schematic, there is a reset circuit with two pushbuttons: The button marked "warm reset" sends an active low signal to one microcontroller, while the button marked "cold reset" sends a ...
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2answers
37 views

Reset pin (15) behaviour of 4026 counter

I'm trying to play with CD4026BE counter and I'm unable to solve the problem with reset pin (15 according to datasheets and numerous examples). In my case, if pin 15 (reset) is grounded with the ...
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vote
0answers
31 views

program resets after ISR for TIMER 2 on pic24F

I am trying to configure the timer2, but every time that an interrupt occurs, the microcontroller goes to the ISR and then starts the main() function again. This are the functions: ...
0
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2answers
70 views

ARM Cortex reset button and debug interface (SWD)

I am designing a circuit using the EFM32ZG222 MCU (an ARM Cortex M0+) and I need to use the SWD interface (with a 10-pin Cortex Debug Connector) along with a reset button. I found a schematic that ...
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1answer
72 views

Connecting Open-Drain inputs or outputs together with one resistor

I had a couple of quick questions. I am designing a board using 10 IO expanders which I'll use as inputs. Each has an !INT pin which is open drain and pulled high to 5v through a resistor. Can I ...
2
votes
3answers
157 views

Reset of a JK flip flop pulse indicator

I've made a circuit with 74HC109 JK flip flops. The purpose is to catch a pulse from two signals and for about 20 seconds keep the stored value (of which pulse came first). My problem is I need to ...
0
votes
1answer
119 views

reset microcontroller

i use dspic micro and ir2104 to drive half bridge mosfet i use 12 volt , 150 watt switching power supply and lm2576 3.3 for dspic. when the mosfet load is 10 watt no problem but when the load is 50 ...
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votes
0answers
54 views

POR Watchdog circuit design endless loop

I've been working on this idea for a reset circuit for a chip I'm doing. I want to be able to reset the chip from the outside world with a reset supervisor (or maybe an RC...), but I also want my ...
4
votes
4answers
181 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 ...
2
votes
2answers
201 views

PIC18F44K22: Can't use MCLR/RE3 pin as input. MCU resets when RE3 is held down

I'm trying to use the 4-bit wide PORTE on a PIC18F44K22 MCU. This port contains the RE3/MCLR pin which can be configured as a reset pin or as an input pin by setting/clearing the MCLRE bit on ...
4
votes
2answers
223 views

ATTiny project resets when plugging in phone

Project I'm not very experienced with electronics and microcontroller-programming yet. I recently (accidentally) bought a couple of ATTiny13A microcontrollers, assuming I could program them using ...
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0answers
446 views

ATTiny85. How do I use the reset pin as an analog input or digital output?

According to this datasheet, the ATTiny85 has 6 I/O pins if we include the reset pin. I used five of them to charlieplex 18 LEDs and I need another one to use as analog input. Would it be possible to ...
2
votes
1answer
107 views

Reset I2C slave chip when master goes away

I have a board with a transformer and a MCP23017. This board is connected to another board via 4 wires which bring over power (+5V, GND) and I2C bus for an ATmega328P acting as the master. The ATmega ...
0
votes
1answer
583 views

What is reset, preset and clear in a counter circuit?

I know this is a basic question. But I want to know the use of Reset, Preset and Clear in a Counter circuit. How do I use them? An example would be appreciated.
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1answer
90 views

Preventing Reset during ESD

I would like to design a RC filter to prevent reset to a SoC during a ESD strike. Assuming the reset net is by default low. And the reset comes from a separate board which connects to the main board ...
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0answers
112 views

ATmega 1284P lockup or stuck in reset after lightening storm, then fully recovers. How to prevent it?

I have a custom Arduino based data collection system which has been running happily, reporting data over a cellular connection on solar power for a few months. After a lightening storm it stopped ...
4
votes
3answers
388 views

Do I need a Reset Switch?

I'm trying to make a ATmega328 run on a breadboard. I am stuck on deciding if I need a reset switch. Do I need one? Can I just unplug and plug in the battery instead? If I do need one, how would I ...
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2answers
79 views

Which is better after rewriting the ROM on a PIC16F? A software reset instruction or a watchdog reset

I am working on a project where the uP can be calibrate at any time. The new calibrated values are stored in the uPs ROM. After the calibration is complete, I have to reset the uP such that the ...
0
votes
1answer
56 views

How to check the source of reset in ATMEGA644p

I am trying to find the source of reset for ATMEGA644p, but I couldn't find the way to do it! MCUCSR gives error in atmel studio as not declared and the datasheet also doesn't have it.
3
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2answers
874 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 ...
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votes
1answer
134 views

STM32 not booting without J-link

I've got a device with STM32F439 microcontroller on it. I flashed the firmware using the J-Flash utitilty (flashed and read back data is same). Then started the application from J-flash: everyting ...
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vote
0answers
115 views

Pulse reset line with long press of a button

This question is a variation of How to trigger reset at long press of button. Namely, I need to pull down a reset line with a short pulse of X length, if a button is pressed for Y>=X or more seconds. ...
2
votes
2answers
386 views

Do I have to debounce MCU reset pin?

I have it only tied to switch via a pull-up resistor on a pic. I'd like to not perform any hardware debouncing to save on costs, but I'm wondering if this could lead to a higher fail rate of ...
1
vote
0answers
47 views

Stellaris Launchpad: Register to store value that can be read after soft-reset

I am working with an LM4F120 Stellaris Launchpad. In my firmware I want to trigger a soft-reset but only once. When the firmware gets out of reset it should read from a register to see wheterh the ...
2
votes
1answer
523 views

Why is there a 100nF capacitor in the Arduino Severino reset line?

While looking at the Arduino Severino (Single-Sided Serial Board V3) schematics I notice it has a ceramic 100nF capacitor in the reset line (marked in red in the picture below). My questions are: ...
3
votes
1answer
270 views

How to find cause of reset in PIC16F microcontroller?

I've worked with other microcontrollers that have a register that I can check on powerup to check a register that contains debugging information on the cause of the reset. Initial searching revealed ...
4
votes
4answers
1k views

PIC16F628A Resetting after relay turned off

I am having problems with controlling a relay with load on it. I am using PIC16F628A. The problem is following: The relay has load. At first it is off. When the microcontroller's output is on, the ...
2
votes
1answer
157 views

difference between POR and other resets

everyone. I would like to ask you about the difference between Power On Reset[POR] and other Resets because in PIC18 controller datasheet i have seen a statement like: ...
2
votes
2answers
611 views

How to trigger reset at long press of button

I am trying to make a button control on/off and reset all in one, but I can't quite get my head around how to design it. It should basically function like a PC power button. If short press it's ...
1
vote
0answers
177 views

MSP430 GPIO behaviour on power off

I have a simple circuit which contains an MSP430 connected to a DAC8551. I'm using PORT1 so have implemented a bit-banging approach instead of using the USCI module (bad, I know). I've noticed a ...
3
votes
2answers
212 views

AVR Reset pin for a long time

I just have a little Question, if I drive a reset pin to low (reset active) of an Atmel AVR for a long time (1 week for example, in fact it'll be really variable depending on the use) can it cause ...
1
vote
3answers
213 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
4answers
394 views

Why does my AVR act weird (resets, data corruption) when receiving a few bytes on the UART?

I have an ATmega644 connected to another device using the UART. After receiving a few characters on the UART the device resets and/or acts weird. Some examples of this behavior: Code before the main ...
3
votes
3answers
180 views

Is there any problems or issues with holding !RESET low on ATMEL ATMEGA328P till rest of board self checks?

I'd like keep an ATMEL ATMega328P in reset for about 4 sec while the rest of the board self checks on startup. Is this OK? Are there any issues that would make holding the RESET low for this extended ...
3
votes
1answer
482 views

Flip flop with load/set, reset, clk, and input

I'm not looking for a hardware language description of the flip flop, but the logic gate level to implement. In verilog, the equivalent I'm looking for is ...
3
votes
1answer
65 views

Reset and clock

In digital circuits (combination & Sequential) which input holds more priority clock signal or a reset signal? suppose we give a input reset in an asynchronous counter then reset will wait for ...
2
votes
0answers
251 views

Relationship between reset pins and SWD functions (ARM Cortex M0)

On many microcontrollers or other devices without JTAG/SWD functionality, there is a reset pin which when low unconditionally and asynchronously forces everything into a known state. On devices with ...
2
votes
2answers
329 views

What could cause unexplained brownout resets?

Context I'm building a 7kW bidirectional two-stage switching converter. Each stage has its own control board and processor. The entire system runs off a common 24V rail. Isolation stage Two ...
11
votes
5answers
4k views

What could cause a microcontroller to unexpectedly reset?

One particularly irritating variety of bug in a microprocessor-controlled system is for the microprocessor to unexpectedly reset. An important tool for debugging this kind of problem is a list of ...
1
vote
2answers
301 views

AVR /RESET pin voltage

The two AVRs I'm using right now (ATmega1284P and ATtiny4313) are both powered by 4.96V. I'm measuring a voltage on their /RESET pins of 6.33 volts. Is that normal? Where is it coming from?
2
votes
1answer
347 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 ...
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vote
2answers
3k views

Connecting the RESET pin of AT8051

How should I connect the RESET pin in a microcontroller (AT8051), and why in that particular way?