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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4answers
142 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
92 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
145 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 ...
0
votes
0answers
120 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
67 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
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1answer
128 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.
0
votes
1answer
84 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
76 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
360 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 ...
0
votes
2answers
69 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
41 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.
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2answers
570 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 ...
0
votes
1answer
97 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
83 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
330 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
42 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
353 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
198 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
786 views

|Solved| 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
123 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
307 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
148 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
161 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
166 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 ...
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vote
4answers
310 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
143 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
400 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
63 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
190 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
272 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
2answers
3k 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 ...
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vote
2answers
258 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
291 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
1answer
2k views

Connecting the RESET pin of AT8051

How should I connect the RESET pin in a microcontroller (AT8051), and why in that particular way?
3
votes
2answers
105 views

Board occasionally resetting when dropped or knocked

I have a board that consists of Arduino pro mini (ATMega328P, ceramic resonator, tactile reset button) SD card I2C sensors LTC3525 boost converter (IC, inductor, caps) Very occasionally, if the ...
0
votes
2answers
2k views

Given a gated SR latch, How do I make it a set dominant gated SR latch?

Another weirdly worded question in my digital logic book. It doesn't specifically define set-dominant or reset-dominant - nor does it show how to use these in practice with drawing circuit diagrams. ...
-1
votes
1answer
61 views

Is RST valid while programming with ISP?

First time designing a PCB board whith a MPC82G516AP (8051),I'm using an external Watchdog Timer chip。So is the watchdog reset valid while programming with ISP?
1
vote
1answer
112 views

Resetting a 74xx164 on power-up

I while a ago I saw a circuit in a datasheet that automatically cleared a 74xx164 shift register on power-up. I don't exactly remember which logic series it was (might have been LS or HC), and the ...
3
votes
2answers
1k views

Reset pin on ATtiny84/85/2313 clarification

I have two questions that I was hoping someone could clarify with a quick True/False. When using the ATtiny85/85/2313 the reset pin is connected to a 10k resistor which is connected to VCC. When ...
1
vote
2answers
288 views

Pullup or direct drive when handling active low inputs/resets?

Active-low reset inputs seem to be a holdover from TTL logic where the falling edge was faster than the rising edge, so the falling edge was decided as more important to increase the maximum possible ...
3
votes
3answers
480 views

Generate a reset signal from a falling edge trigger

I'm working on a microcontroller design where the mcu is placed in hibernation mode, and can only be awoken by a pulse(high-low-high) signal on the reset pin. (active low) As a wake-up source i'm ...
2
votes
2answers
125 views

Electronic Reset SW

Normally, there is a mechanic button at the end of the RESET SW pins on the mainboard. Now, I like to create a way to electronically trigger the reset function of my mainboard from another computer. ...
3
votes
1answer
133 views

PICKIT 3 resets PIC16 three times upon reprogramming

I am using the PICKIT 3 with MPLAB X with the default setings. When I press F6 to build and run my code, I notice that the PIC16 resets three times: twice with ...
3
votes
3answers
179 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 ...
11
votes
2answers
7k views

What values of resistor and capacitor to use for AVR reset pin isolation?

Background... I'm a newbie to AVR applications. I recently built two ATTINY13-based circuits (glorified LED blinkers) which worked correctly (independently) on the breadboard. When I combined them on ...
3
votes
1answer
820 views

Using AVR reset pin as ADC

I am using an ATTINY13 for a toy application. It simply blinks LEDs in specific patterns. I decided to add a "speed control" using a potentiometer but the only pin I had left is the reset pin. I've ...
2
votes
1answer
1k views

STM32 NVIC interrupts after a reset / power-on

I have a few active-low signals that I want to interrupt on. During normal operation, the interrupts work just fine. However, on reset / power-on only rising edge is detected. In other words, on ...
6
votes
3answers
260 views

Using reset controllers with modern microcontrollers

Are reset controllers necessary for modern microcontrollers, such as the LPC2138 or 9S12XD256? Most ARM processors I have seen have their own brown-out detectors and reset properly, and I don't see ...
1
vote
1answer
853 views

Is RESET* on the XMEGA disabled when using the PDI interface?

When PDI CLK is connected on the XMEGA (also the RESET*) pin, can this pin still be used to trigger a reset on the chip? If so, how does the chip tell the difference between PDI being used as a clock ...
0
votes
2answers
1k views

Resetting XBee with an Arduino

I would like to be able to reset an XBee with an Arduino by connecting the reset pin on the XBee to a General I/O pin on the Arduino. I'm wondering if any additional components (transistors, resistors ...