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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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 ...
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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 ...
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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
...
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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 ...
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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 ...
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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-...
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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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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?
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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 datasheet: ...
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Connecting the RESET pin of AT8051
How should I connect the RESET pin in a microcontroller (AT8051), and why in that particular way?
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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 ...
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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. I'...
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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?
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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 ...
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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 ...
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HVAC furnace igniter causing micro reset
I am using a combination of Microchip PIC18F4520 and PIC16F73 in a controller which interfaces multiple heating systems for different applications. One huge issue I am running into is fossil fuel ...
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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 ...
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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 ...
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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. ...
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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 the ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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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 ...
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Electrical reset to a SIM card
I have a SIM card reader connected to an ARM, and I'm trying to get the SIM to send an Answer To Reset (ATR) and to get the reader to capture it.
As I understand, an ATR is sent after an "electrical ...
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STM32: Performing a software reset
I am trying to perform a software reset of my STM32F2. (Reference manual available here.) The relevant page of the reference manual (page 80) gives little information. Basically, the ...
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Do AVR registers and ports need to be initialized to zero?
During the initialization routine of my code I use to do such things as:
clr r0 ; will always stay zero
and:
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Where reset happens with SR flip-flop
In one of my classes we are learning about circuits. For homework, we have to create a finite state machine for a vending machine using an SR flip-flop. The machine can either take a nickel, dime, or ...
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Hard resetting an STM32
My STM32 is behaving weirdly, to say the least. What is the best way to "hard reset" an STM32? I've tried pressing the "reset" button, and unplugging/replugging everything, but it seems like the ...
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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 ...
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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 ...
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Device is reset when switching power sources
I use a home weather station. It is powered by two AA batteries (2 x 1.5 = 3.0 V nominal). The problem is that it eats more than 1 mA and that is quite a lot of power and I must buy a new pair of AA ...
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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.
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Atmega328 reset pin not working after re-burning Arduino boot loader?
For a bit of background you might want to read
ATmega328 with Optiboot not compatible with Arduino?
But I will summarize anyway. I have some Atmega328 chips that shipped with the optiboot ...
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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 ...
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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 ...
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MSP430 Illegal Instruction
A few questions here along the same lines, I'm looking at the datasheet for the MSP430x2xx family (I'm using the MSP430F235 FWIW). It says there in section 2.2.4 that "illegal instruction fetch" is an ...
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Controller Resets after Enabling Cache
I am using a MCF5253 controller which is based on Coldfire Architecture.
It has 8KB of Instruction Cache.
Everything was working fine till I enabled it's Instruction Cache.
Now what's happening is ...
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Does reset do the same thing as shutting off the power to this device and turning it back on?
I am trying to control a serial dataflash memory through an mbed. It is an AT45DB021B and the datasheet is here. It has a reset pin that I have wired to the mbed so that a software reset can be done. ...
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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 ...
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(Updated) Strange reset behavior with ARM9 processor
I'm working on debugging a boot problem with an Atmel AT91SAM9G20 board. Everything goes great for the first 700 ms or so. It seems that about 700 ms after reset, the processor freezes. What's curious ...
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Is it possible to reset NXP LPC2100 microcontroller from code
I'm curious? A watchdog timer could do this, but I would like to do it manually.
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Arduino reset with FTDI breakout question
How do you get the SparkFun FTDI Basic Breakout board to auto reset?
I still have to hit the reset button for any Arduino clones when I use the breakout board. I have tried connecting to the DTR pin ...
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Arduino chip wipe on reset
Does the Arduino chip get wiped of any (uploaded) code when you press the reset button?
and
Can you retrieve the code that is currently on the chip?
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