Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [power-on-reset]

12 questions
6
votes
3 answers

Put SR latch to determined state during power on

I'm trying to build a circuit that will stay turned on once triggered, and ordinary SR latch seems like a perfect solution. However, I cannot find an efficient way to turn SR Latch to deterministic state on power on. What could be the simplest yet…
Georgy Farniev
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4
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3 answers

CD4017 resetting itself when load connected

Ok to the issue I have been plagued with for some time now. The circuit is powered by a 4s Battery Pack (max VBAT = 16.8V, well below the CD4017 max V of 20V) After the Power-ON stage it is branched out to Voltage Regulators, see below. I have…
Aotearoa_DEV
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3
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5 answers

Power on reset discharge circuitry

While looking at USB 3.0 Host Controller reference design, I came across this circuit: They used LL4148 diode in this design. Note: PONRST goes directly to the Host Controller IC. I'm trying to understand the idea behind why is this circuit…
Firas Abd El Gani
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3
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2 answers

Question about capacitor and resistor in "power on reset circuit"

What I am reading has this circuit: It also has this description: In analog power on reset implementation, the time and voltage threshold factors are characteristic of an analog circuit. The time period of the reset state is determined and…
user394334
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1
vote
2 answers

CMOS 4031 -- how was power-on initialization done in its intended applications?

I'm looking at using a CD4031 as a digital delay line in a project I'm working on. In this project, I'd much rather said digital delay line power up in an all-0 state, lest errant 1s clocked out of it cause the output to turn on something that it…
ThreePhaseEel
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1
vote
1 answer

How would I externally drive the Reset signal alongside a classic Power-On Reset circuit?

Say I have a D Flip Flop and I have a resistor, capacitor, diode, and Schmitt buffer to keep its reset line low for a few ms during startup (as per this answer) This takes care of power-on, but during operation of the circuit if I need to drive…
Orotavia
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1
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1 answer

Reset when battery powered device receives USB power

Device (microcontroller) is powered by battery or USB, through load sharing circuit. When no USB, operates on battery. When USB applied, USB powered. I want device to reset once when USB power applied. I've found voltage supervisor IC's but all…
Calum Nicoll
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0
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0 answers

Shared control at power-on-reset

I have a D Flip Flop, whose /set line is controlled by an ATmega, and its output (Q) is connected to the /WAIT line of a Z80 processor. Of course, I need that at power on, the Q output is set HIGH to prevent the Z80 from entering in WAIT. I think…
ozw1z5rd
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1 answer

Reset mainboard from Raspberry Pi

I have a desktop computer with an Asus mainboard TUF_GAMING_B550-PLUS and a Raspberry Pi 4. I log in remotely to the computer, but unfortunately from time to time it has an operating system issue, freezes, and has to be reset. I want to do this…
user7468395
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2 answers

Behaviour Variables stored in non volatile memory after RESET

I need to know if a variable stored in a non volatile memory, after a Power On Reset do this variable return to its default value, or it keeps the last valid value before the reset
Oussama El Hassouni
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0
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2 answers

AVR reset pin capacitor causes chip to enter bootloader on powerup

I have a circuit using an ATmega32U4 and am using the Arduino Leonardo/Micro Caterina bootloader (the one that comes with arduinoIDE v1.8.13). The problem I am having is on power-up (via USB connection) the AVR enters bootloader mode instead of…
Scott
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What does the MCP4725 Power-On-Reset (POR) value indicate?

I managed to read from an MCP4725 using I2C. In the second byte below, the POR value it gives me is '1' (the whole byte is 11000000) I know that if RDY/BSY = 1, it means the device is ready to write its EEPROM. When does POR = 0? What does it mean…
Christianidis Vasileios
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