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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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Microcontroller resets with motor driver (L293D)

I am making a simple robot with 2 BO motors driven by L293D on ATmega328P (took out from Arduino Uno). The robot when tested on Uno works fine. But when I put it on the board that I have designed (as ...
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1answer
37 views

Reset MCU with a 1-0 button

I am working on a silabs C8051 MCU. It has a sleep mode which should be woken up by a reset. The mcu should start working (wake up from sleep) when the button in connected to Ground (Otherwise it is ...
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44 views

STM32L4 Reset Issue

I have been facing a reset issue. My controller resets randomly. I have Codded for the source of reset at the begin of the routine. For the testing the code I made the system reset on purpose and ...
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1answer
52 views

Understanding MCU Reset Pin working

I am using this Microcontroller NXP MCU I am trying to understand the RESET Section of the microcontroller. 1.On page 83, it is given as MCU reset is a bidirectional pin. So, It can drive other ...
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3answers
110 views

Multiple Reset Synchronization

I have two active low async resets (rst_na and rst_nb) and associated two clocks (clk_a and clk_b). Assume Block B required ...
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3answers
93 views

HDL code convention for register resets

When it comes to (synchronously) resetting registers in HDL (I'll use Verilog), is it considered bad practice to code the reset combinatorially? As far as I can tell, the following two snippets are ...
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1answer
49 views

How is asynchronous reset physically implemented in a flip-flop?

In Cliff Cumming's excellent paper on asynchronous vs synchronous resets, the following paragraph about the risk of metastability appears on page 19: Attention must be paid to the release of the ...
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0answers
33 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 ...
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3answers
1k views

I know what a Reset signal is, but a Set/Reset signal? Isn't that impossible?

A schematic by Lattice Semiconductor includes the diagrammed D flip-flop. This D flip/flop accepts, among others, a Set/Reset signal. I would have understood a Set signal. I would have understood a ...
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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 ...
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3answers
124 views

Resetting CD4017 Counter when power source is OFF

I found the circuit below online and I have two questions about the reset switch. Does it help to click the reset button when power is OFF? I mean, does it clears the memory of the CD4017 chip when ...
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2answers
72 views

Is it possible to generate internal reset pulse in verilog with machxo3lf fpga?

I have a board without Reset input for my design. But I need to reset at fpga startup. Is there a verilog solution to generate this pulse ?
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48 views

RESET signal to multiple ICs

I have 3 ICs in my circuit that have active-low reset signals. By pressing a tactile button I would like to reset all 3 of them. two of them operates with 3.3V and one of them operates with 1.8V. ...
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1answer
153 views

STM32 power down procedure

This is my first time to design STM32 circuit and I have no experience about the power down procedure. In my opinion, it may be very rude to shut down the power supply as soon as the user presses ...
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1answer
85 views

Weird reset problem in FPGA Design

I'm facing a weird problem. I have written an UART and a FSM. This design just print some text on the screen automatically, just after loading the bitstream. The problem is: when I load the bitstream, ...
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1answer
54 views

Safety Relay Circuit

I am looking for a way to add a relay-based safety feature to my BLDC controller. In case of an emergency the user must be able to push an e-stop (probably consisting of an NC contacts) completely ...
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1answer
71 views

circuit that disconnects a connection

I'm designing a circuit that will disconnect a connection when 5 consecutive square wave pulses are missing. If less than 5 consecutive pulses are missing then I want to reset the counting process. <...
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2answers
59 views

ESP 12E resets on connecting to a client in WiFi mode

The image above is my schematic for ESP12E. I soldered the circuit as shown. When ESP is in WiFi mode (like an AP), and I try to connect to that from any device (laptop, mobile) there is a very high ...
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3answers
128 views

Delayed, active low, short pulse for reset

I am attempting to create a circuit using a TUSB2036 usb hub IC that automatically starts when it is powered on. The datasheet states for the inverted RESET pin RESET is an active low TTL input ...
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2answers
235 views

Press and hold the reset button to reset AVR!

I connected a tactile switch to the AVR reset button according to the circuit below. every time I press the button the AVR resets itself but my question is: Is there a way to make this button acts ...
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1answer
45 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 ...
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2answers
48 views

Use single GPIO out to reset multiple lines

I want to use a single Raspberry Pi GPIO out to reset two lines: LCD and CTP. What would be a correct schematic ? Can I simply connect both lines together ? Both devices are "no-name", i.e. no ...
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2answers
79 views

What is a dc reset?

I read this sentence from a book: "MR is a dc reset". It said about master reset leg in a counter IC. I have been searching but found nothing related to this terminology. I wonder what a dc reset is?...
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3answers
385 views

Reset pulse generator for ESP8266

I am trying to generate a reset pulse in order to wake up an ESP8266 device. The ESP8266 supports a "deep sleep" function, in which it consumes very little power. However, the only way to wake it up ...
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2answers
115 views

Resetting Ram problem in VHDL

Hello I am making a VHDL project in which I am doing some image processing. Color data of pixels are held in Rom and operations are done on Ram. However, when I try to reset the ram from the rom. It ...
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Cannot read from RAM in Vhdl

Hi for some image processing purposes, I must read 12-bit color data of a pixel from Ram and display it on screen through VGA cable. However, my code does not read from Ram and all I see on the ...
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1answer
81 views

How do you do a software reset of the am355x (like on the BeagleBone Black)?

Is there an easier way to do this than setting up a watchdog and waiting? Using only software (no tying a GPIO to the reset pin)?
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0answers
105 views

PIC32 Wake From Idle reset type - what can cause this?

I have a system containing a PIC32 microcontroller that controls the switching of arrays of electromagnets. These previously asked questions give background information about the system in question ...
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1answer
46 views

Protecting reset pin from overvoltage

I'm designing a board with a control port. The control port allows an external controller to reboot the system by pulling the BRD_RESET low, effectively restarting ...
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3answers
269 views

DAC behaviour on reset / startup LPC1768

I am programming a mbed LPC1768 for a constant current discharger. I plan to use the DAC output on the LPC1768 for setting the current in my discharge circuit. edit: The trouble i am having is ...
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2answers
504 views

Omron G3MB-202P SSR reset loop

I am using an Omron G3MB-202P SSR to switch an AC outlet on and off as depicted in the below sketch. This works fine. However, when connecting a phone charger to the "controlled" AC outlet while the ...
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1answer
216 views

atmega32u4 reset, bootloader and fuses

I have a atmega32u4 from factory with dfu inside. The HWB is pull down, and RESET pin is pull up. The first USB plug, dfu programmer appears on my Linux box. I upload the firmware without problem. ...
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3answers
412 views

Asynchronous reset

I am designing an FPGA that will include state machines and counters both of which needs to be reset, i have heard that it was always better to use synchronous resets, is it true? I am not sure that ...
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0answers
51 views

Can I use JTAG Boundary Scan if SRST is not available

I am attempting to integrate JTAG Boundary Scan onto an existing ARM9 board using SAM-ICE as the JTAG Emulator. One unfortunate oversight is that CPU/System Reset (...
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2answers
255 views

Rowley Crossworks STM32 Start from Reset

I am using an STM32F4 with the Rowley CrossStudio for ARM. It is not clear to me how to have the MCU start from int main() on reset (i.e. power up the device). I thought building it in release mode ...
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1answer
129 views

Avoid reboot of USB serial device when another USB device is inserted [closed]

EDIT 7/7/2018: Can't add an answer because this question is closed however there is an answer here. It is not a problem related to Windows only. The reset is caused by hardware behaviour, the ...
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1answer
290 views

STM32 Doesnt Run After Reset

I'm having the odd problem where a STM32F4 wont resume operation after pulling NRST low. Power cycling the STM32F4 works just fine. NRST is configured with a 0.1uF cap to ground. It has no other ...
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1answer
210 views

atmega328p keeps resetting

i program my atmega with USBasp ,and i set the fuse bits hfuse:0xC9 and lfuse :0xff. when i upload my simple code ...
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1answer
108 views

Unable to turn off / reset SRAM 23LC1024

I'm trying to reset an external SRAM 23LC1024 (turn it off and turn it on again) which connected to my Arduino Mega 2560. I need to do that because I want to profile the SRAM in an attempt to ...
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1answer
269 views

Attiny 45 use reset pin as analog input?

So after debugging for 6h+ I am stuck at that the reset pin of my attiny 45 needs to differentiate between two voltage levels. (5v and 3.7v) Ive seen in the datasheet that this pin has an adc. So it ...
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1answer
155 views

AVR Program doesn't start running sometimes

I've written a little watchdog firmware that runs on an ATtiny85. The idea of the firmware is to: wait 10 seconds after power up and ignore signaling during that time after that expects a signal to ...
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1answer
248 views

Using both Synchronous and Asynchronous resets in a design

I am working on an FPGA design in which I also have to integrate several legacy IP cores. I use asynchronous assertion and synchronous de-assertion for the master reset signal in my design. I ...
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1answer
110 views

Power on reset and watchdog signal combination question

I'm working with the i.MX RT1050 processors and designing a POR circuit. I found the following circuit in the reference design but I don't understand how it's meant to work. The UM805RE is a voltage ...
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0answers
41 views

User Defined reset in VHDL

I am making a synchronous D-FLipFLop circuit for an assignment about car blinkers, I am only having a final issue with what the system does and should do when i change blinker direction immediately (e....
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2answers
389 views

How can I return an Arduino digital pin to floating state?

I am trying to setup a programmed reset function for a 3.3V BlueTooth module that resets when its reset pin is pulsed LOW for a short period of time. There is a 47K pull-up resistor in the BT module ...
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2answers
111 views

Bi-Directional MOSFET level converter problem

I am using standard schematic of level shifter. It is used to communicate with avr and sometimes reset it. Everything works fine except for reset line. After the first pulling down I am not able to ...
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1answer
89 views

Atmega128 improper reset

I'm using Atmega128L controller. One of the primary tasks is to control a linear actuator. The actuator supply and controller supply are different(initially it was designed to share a common ground). ...
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0answers
173 views

Reset pin voltage level problem

There is a very similar question regarding voltage problems at the reset pin of a microcontroller, but using a pull- down resistor here. For my current project, I'm using a Kinetis K64 MCU, the ...
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1answer
209 views

Power & Reset in momentary switch in analog circuit

So I am designing a circuit and wanted to implement both power and reset in one momentary switch. What I mean is, if the switch is pressed, it sends a reset signal (4.5v), but if it is held for x ...
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1answer
132 views

How to reset microcontroller after X amount of hours/seconds? [closed]

I know there are similar posts to this I am just looking to see if there are any new more efficient solutions. I have a MCU and I am looking to add a circuit in between the power supply and the MCU ...