Questions tagged [reset]

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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6answers
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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 ...
26
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5answers
31k 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 ...
15
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5answers
4k 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 better ...
5
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2answers
6k 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
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1answer
727 views

How do I extend the output (high) time of my circuit (retriggerable)?

I need help with the design of a timer delay circuit for the output of a sensor circuit which can keep the output HIGH for an adjustable time range (about 1 to 10 min), after the digital output of the ...
6
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3answers
598 views

Intermittent MCLR reset on PIC32 - involves switching electromagnets

I am working on a project that involves a lot of switching of electromagnets. The switching is controlled by a PIC32MX6xx-series microcontroller, which determines the required states of 80x 12 VDC ...
5
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4answers
8k views

What is the common pin configuration upon microcontroller reset?

I have looked through two datasheets and user manuals now for two different microcontrollers (LPC2387 and STM32F4xx), and I haven't found (probably missed) anywhere where the initial state of the GPIO ...
15
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5answers
14k views

Reset: synchronous vs asynchronous

I've been working with fpgas for years, and always used synchronous resets for every parts (that need it) of my circuits. It helps the circuit to be globally reset at a given clock cycle. However, I ...
9
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5answers
6k views

How does a latch determine its initial state?

How does a latch get its initial state? I'm guessing that it depends on race conditions and which ever condition comes first then that is the state that the latch starts off with.
3
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3answers
4k views

ATmega32 factory reset board

Is there a reset board available (I mean schematic, link, tutorial or anything else) out there for the ATmega32 microcontoller (I heard about a high-voltage reset board, and I found some links for an ...
8
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1answer
5k views

How does the Arduino Deumilanove Auto-Reset Function work?

I'd like to hear some explanations as to how the Arduino Duemilanove resets the ATMega328P over USB through the FTDI FT232R transceiver. I know it involves the IDE playing some games with the DTR ...
20
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7answers
5k 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 ...
5
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2answers
3k 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 ...
5
votes
4answers
543 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 ...
3
votes
2answers
2k 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 H-...
3
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2answers
231 views

What is automatic global reset on FPGA?

I recently asked a question that ended up involving answers about an automatic global reset capability that FPGAs have, and though the question got solved, I'm still quite unclear about this, and ...
3
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1answer
2k 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, ...
1
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4answers
3k views

Is power cycle reset different from reset pin reset?

I am using custom built arduino uno for a home automation project. Sometimes, the arduino locks up due to electrical noise or sparks in the ac lines. More details here. I tried conducting some ...
1
vote
2answers
972 views

Multiple buttons connected to reset pin

I'm building a battery powered device based on ESP8266. There are few buttons (lets say 4 at the moment). After pushing any of them ESP should perform some action ...
4
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1answer
3k views

Can an ATtiny with RSTDISBL programmed be reprogrammed over ISP?

The ATtiny85 datasheet, on page 152, seems pretty clear on this: After this fuse has been programmed device can be programmed via high-voltage serial mode, only. But elsewhere, on page 28, it ...
4
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3answers
2k 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 ...
3
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2answers
1k views

BeagleBone Black reboots periodically

My BeagleBone Black reboots periodically after some random time (> 5hours)? I am totally stucked with ideas, I have my app working for that some random time and system gets reset. BBB works on Debian ...
2
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2answers
128 views

Why are registers being turned on to 1 before reset/on button is hit on FPGA?

I am writing a really simple program on Verilog for my FPGA to have an LED blink once a button is pushed. Here is the code I have written: ...
2
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3answers
6k views

STM32 reset not work

Background: 1.5% of products which use STM32F107 didn't work after using 3 months; Lithium battery is the power supply source. The products were used in car. This phenomenon suddenly occured ...
1
vote
1answer
8k views

Xbee Factory -Hardware reset without serial communication

I'm using "XBee 802.15.4 Module" After successful connection with X-cut & made a "+++" it responded "Ok" Then is stopped working .... I tried to reconnect to it again & failed .. it no ...
0
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1answer
126 views

Building a T flip-flop with enable and reset using only a JK flip-flop that has no enable or reset, and use some necessary logic gates

I am confused about whether if I should use don't cares to fill in the J and K on the state table, or just use keep and change. If I use don't cares I will not get any Q inputs (as seen on the K-maps),...
0
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2answers
3k views

Power-on Reset for CD4017 gives unexpected results

In the circuit below, a 555 timer produces approximately 1 pulse per second, and the CD4017 counts pulses. The initial state of a CD4017 is undefined, thus I need a reset pulse on power up. In the ...
0
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1answer
132 views

Designing a special 4-bit counter with flip flops

This is a normal design of 4-bit counter using D flip-flops The outputs Q0 to Q3 are connected to diodes. I want to modify this counter in such a way that it follows the following counting sequence ...
0
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1answer
52 views

Isolating Power in Communicating 5V Sub-systems

I have been plagued by a sensor sub-system which, when connected to my base micro-controller platform, intermittently causes issues that I would categorically associate with power sequencing issues at ...