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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78 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),...
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USB to ethernet chips like LAN7850 require GPIO to RESET pin?

I am designing a PCB which uses LAN7850 chip This is the first time I'm using such a chip and I'm very newbie to PCB designing. Please advise if this Chip requires a GPIO pin from the ...
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Resetting 555 via Transistor - RESET PIN LOW TOLERANCE

I have a circuit with a NE555DR timer that generates a pulse. The reset is held low and lifted when a voltage of 5 - 24V is applied to P0-3. A PNP transistor MMBT5401 that pulls pin 4 to ground when ...
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Basys 3 FPGA sequential circuit reset remotely?

Since the COVID-19 pandemic, I'm teaching Verilog lab online. I let each student remotely connect to a computer having Xilinx Vivado installed, a Basys 3 board connected and powered on, and a camera ...
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One-way JK flip-flop using 74xx109

I want to design a flip flop circuit that effectively has one input and one output, as well as a reset trigger, along with clock and power, using a 74ACT109 JK flip flop. Basically, the output and ...
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127 views

What is the use of NRST pin in STM32F401RCT6?

What is the use of the NRST pin in STM32F401RTC microcontroller. I am using the SWD interface to program and debug flash memory of the controller. I am finding NRST pins in both microcontroller as ...
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64 views

Hard Reset variable change in MCU

I have an activation system with a unique password per activation operation. If the system goes down or is not working correctly and I need to reset it to a operational state I could design a hard ...
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STM32F4 read protection cause MCU hang

I've faced a problem using read protection on STM32F412. When read protection enabled from Level 0 to Level 1 MCU hangs and does not recover after the reset with reset the pin, only after a power ...
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36 views

Handling of reset with multi bit clock domain crossing

I have an SoC design with two clock domains, each with it's own asynchronous reset (which roughly means asynchronous assertion of reset and synchronous de-assertion). I am trying to pass a 64 bit ...
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90 views

Verilog finite state machine won't reset (asynchronous) current state to initial state (shows xx)

I have mostly worked on VHDL and I have recently started learning Verilog. I wrote a Moore Finite State Machine (FSM). The FSM is not resetting properly as current state upon reset doesn't go into ...
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MOSFET gate spikes when load is disconnected

I have a system that has two fan banks driven by MOSFETs. The fans are mounted on two sides of the enclosure on ~2 ft cables. After one second from system turn-on the microcontroller turns these FETs ...
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Desoldering CPU from PCB or holding it in reset

I am currently working with a NAND flash that I want to dump. The goal is to take a look at the data that is stored in the filesystem. To do so I soldered 8 wires to the NAND flash to access it while ...
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189 views

Remote reset circuit does not work

I have a custom board based on an Atmega168A which I would like to reset when the power switch to the on-board LEDs is switched off. Resetting the uC by shorting RST and GND works on the ICSP ...
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Microcontroller working voltage + brownout circuit

I'm working with LPC1769, but this applies to any MCU. The datasheet states that the power supply range is from 2.4V to 3.6V. The included brownout detection circuit triggers a warning interrupt ...
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59 views

Uninterruptible Power Supply - Reset the load when power is restored

My system is powered by a redundant supply (UPS). When the input power supply is removed, the system detects this event and it performs a safe shutdown (actually it is a microcontroller that enters a ...
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ICSP + FTDI for ATMega328P

I want to have this "debug" header with 10 pins (I could probably get away with 9) and I am wondering if the DTR pin is ok to be filtered by a capacitor for ICSP. This is how I am sourcing these pins:...
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AT91SAM7S512 Oscillator, GPIO, & Reset questions

I just need some clarification of my circuit Oscillator: So for my circuit I want to be able to program it via USB, the datasheet gets a bit confusing to me tho. If I read the datasheet correctly I ...
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42 views

Triggering CD4026 Reset w/ a CD4017

I am trying to get a CD4026 IC to reset at 6 for a digital clock project. I have some 3-input AND gate IC's but there doesn't seem to any unique conditions that would work. I do have some CD4017 and ...
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STM32F072C8T7 needs hardware reset upon power on to work!

When the device is connected to the ST_LINK, after firmware upload, it works perfectly fine. When I remove the ST_Link and then turn OFF and ON my device, it does not work, unless I initiate a hard ...
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“recommended that CLK begin toggling within 150 ms … to ensure long-term reliability of the device” — why?

In Intel's Pentium Processor Family Developer Manual, regarding the CPU clock, it says that "it is recommended that CLK begin toggling within 150 ms after VCC reaches its proper operating level. This ...
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Board is getting reset when I lower the temperature in Thermal Chamber

I have a board which I put in the thermal chamber. I increase the temperature inside the thermal chamber to 85degC. Soak it for 2 hours and note some readings. Then, when I change the temperature to ...
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42 views

Decoupling on Power-on-reset-IC

Is it a good idea to place the usual 100nF decoupling capacitor on a power-on-reset chip? Mightn't that influence its behavior on brown-out or power dips? What is the best approach here? The power-...
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Can the watchdog on an STM32F373 trigger a reset while the RESET pin is held high?

The reset pin on an STM32 chip is being pulled high by a Raspberry Pi Zero W in the field via GPIO pin BCM 17. Will the watchdog on the STM32 be capable of triggering a reset while the pin is being ...
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235 views

Program ESP32-CAM via FTDI without manual reset?

When programming the ESP32-CAM with an FTDI, I proceed as follows: Connect GPIO0 to GND. Reset the ESP32-CAM. (by cutting power)...
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What is the proper way to reset attiny85?

I have 3 attiny85 on my pcb. And I want to have software controlled reset for them. A separate STM32F0 microcontroller is responsible for the reset. I have two states from the STM32F0 to pull up and ...
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167 views

Lattice MachXO2 reset

After reading about GSR/PUR facilities in Lattice FPGAs, I'm still a bit puzzled about how to actually get the proper GSR/PUR-based reset functionality on an actual physical FPGA chip. In the How to ...
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133 views

Flip flop asynchronous reset timing

Let's say you unassert an asynchronous reset signal to a flip flop after you need to to meet setup timing but before the positive edge of the clock. You're in trouble right? Now let's say you've got ...
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164 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 ...
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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: ...
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115 views

How should a watchdog timer be used? [closed]

I've seen and written programs in which the internal watchdog just resets in a super loop and trigers only when something goes wrong and forces the whole system to crash. I've also seen it can be ...
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STM32F030CC reset into system memory after NRST deassertion

I did lots of search before this post here. The problem I met is STM32F030CC reset into system memory after NRST deassertion. The burned-in-flash program can run well after POR, but not any more after ...
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STM32F103 timer behaves differently after hardware reset instead of st-flash reset

I'm learning to program the STM32F103C8 Cortex-M3 (on a BluePill board) and was playing around with the general purpose timers (TIM2 to TIM5) because I wanted to time some routines. In my simple ...
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160 views

Finite State Machine and Reset Signal

let's consider a certain finite state machine, for instance a Mealy Machine: I was told that it cannot work properly in absence of a reset signal (for the State Register), since we would not know the ...
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91 views

esp8266 reset - power consumption

I am working on project with esp8266 UC powered with 3.7v lithium ion battery, where the reset pin is pulled low to keep it OFF. I would like to know if my battery were to be consumed with this ...
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156 views

Is Brownout Reset Circuit a standard or optional safety feature in an MCU?

I've been using STM32 MCU's without paying attention to the BOR circuit: Some datasheets indicate that the device has a built-in BOR circuit but some doesn't include such an information. Is it ...
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108 views

Arduino nano resetting after solenoid valve fires

I'm trying to control small, plastic 12V solenoid valves with an Arduino nano. I have an Arduino nano hooked up to a Sainsmart 4-Channel 5V Relay Module, and finally connected to the solenoid valves, ...
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115 views

Atmega328pb microncontroller hangs

I've been working on a project with Atmega328PB microcontroller using both the UARTs for communication. The controller runs fine for a long time but all of a sudden it does not respond at all. It ...
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69 views

Open drain voltage detector NCP301LSN45T1G

I have to use a voltage detector to detect a decrease in voltage to reset a microcontroller. I have found the NCP301LSN45T1G to do this. But I have a question about the Reset Output current (N-...
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254 views

Problem with the reset circuit for a MCU

I need help by understanding the problem with an existing MCU circuit concerning the Reset PIN (STM32 Cortex M0+: STM32L071K8): It seems something in the circuit is wrong, since it works only when I ...
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283 views

STM32 Reset Reason - detect debug reset

In my project I want to set the configuration of the RTC based on the reset source. If a reset is done via hardware reset NRST, the RTC shall be set to zero.If there was a reset due to wake up from ...
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Cortex SWD pins disabled

I am trying to flash an Ambiq Apollo via SWD. The problem is that my debugger is unable to connect to the board. Initially, i though that the SWD pins would simply be remapped by software on the MCU....
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Relating RAM usage with stack allocation and random resets in a microcontroller

This might appear to be too much data way too scattered to understand, but I'll make a genuine effort to explain. Controller: R5F111MJ (ROM 256KB, RAM 16KB), RL-78/L1C family. Datasheet can be found ...
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381 views

Resetting of NodeMCU ESP8266 in deep sleep

I have been doing a project as my first project to learn ESP8266 applications. My project is a temperature and humidity values data logger and upload the data to Thingspeak. The sensor used is DHT11. ...
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124 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 ...
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stm32 - is there a factory reset?

for the past couple of months I have been developing software for a custom build board. Due to a non disclosure agreement i am not allowed to share the schematics , PCB layout or software of the board....
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281 views

Orange Pi zero hardware reset

I have been working on a development board for the Orange Pi Zero platform. I want to add a button which allows to restart the board. Is it possible to implement such functionality?
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238 views

What code issues could persist past a reset? (STM32F103)

I have a project running off a Bluepill board (STM32F103C8T6) that ceases to function only after it runs for ~6 hours. Up to that point it behaves totally normally, and UART logs don't indicate ...
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46 views

Eliminating power-on state changes caused by input signal fluctuations

I have a circuit that uses several comparators to read an analog input signal and control some downstream digital logic. When the device powers up, the logic states fluctuate because the input signal ...
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135 views

SAMD controlling BLDC resets during high current spike; EMI problem?

I have been making a brushless DC motor controller that is controlled through an ATSAMD21E16L and a MIC4609 mosfet driver. At low average currents of 2A or so, I drive the motor just fine, but when I ...
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239 views

Power drop on AC-DC converter due to relay

A uController circuit is powered with an AC-DC converter. This circuit in turn acts on some relays to turn on and off some loads. We have two bi-stable relays and another simple relay (Omron G5DN-1A) ....

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