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Questions tagged [gpio]

GPIO is an acronym for general purpose input/output. The term is typically applied to a pin on a microcontroller (or other device) that may be changed between an input and output under software control. It can be used for an application defined purpose, as opposed to being constrained to a single designated function.

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How the GPIO works internally?

I have a fair understanding about how to configure as input/output enable pull-up etc. While going through the datasheet of ATTiny85 (The same diagram also there in ATmega328p) I have seen the ...
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Decent MOSFET for a beginner to learn from?

I am relearning MOSFETs, but more importantly I would like to focus on building some basic circuits and learning practicality over theory. I have a BSEE but haven't spent much time outside of class on ...
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Output mode configuration on GPIOs: When to use push/pull vs open drain?

Hello guys I'm relatively new to Embedded engineering. I wanted to know if there's any specific rule that experienced embedded engineers use when selecting when to use one of these output ...
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Treating an STM32 MCU's unused pins and reset state

I'm using this MCU from STM2 on a board and the PCB layout is as follows: I will not use several MCU pins, so they are disconnected as shown above(pin 6, 7, 8, 11, 12 ect.). Also I cannot do any ...
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Can I safely use the GPIO or opto-IO pin from Basler industrial camera to drive a 64 mW LED?

I've got a Basler aca2440-20gm industrial camera. This camera has configurable GPIO and opto-IO pins. If it's possible to do so without damaging the camera, I'd like to drive a 20 mA 3.2 V LED with ...
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LED without resistor?

I have an LED with a 3.3v supply and 3.2v forward voltage. The cathode is being grounded (very sparingly) by an STM32 which can sink up to 20 mA. Can I get away without a resistor?
marc6bbs's user avatar
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How does this industrial camera's digital input circuit work?

Industrial cameras I use have a GPIO pin which looks like this when used as an input: Source: https://docs.baslerweb.com/circuit-diagrams-(basler-cameras)#gpio-input-line I'm curious about how it ...
relatively_random's user avatar
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Using a transistor to digitally press a button

Relatively new to electronics so don’t know all of the terminology, so please excuse me if I express things incorrectly. I have a fan remote that I would like to control using a Raspberry Pi (photo ...
Antheloth's user avatar
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switching 2 mosfets with 1 signal

Hi. I'm trying to switch between 2 LED with 1 GPIO and not sure if I've designed correctly. C2_CC_CTRL = GPIO i wonder when GPIO signal is "high", Q14 MOSFET = "ON", D29 LED = &...
3clocks's user avatar
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Detect logic 1 with 5V on 3.3V GPIO pin

I need to detect a logic 1 by applying 5V to a GPIO pin of an ESP32-C-DeVKitC-02. However, I don't think the GPIO is 5V tolerant. My questions are: Why can 5V already be to high for a GPIO? Doesn't ...
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What happens if misconfigured input GPIO delivers 3.3V if it is connected to 3.3V to detect high?

Let's say I have GPIO0 on an ESP32 which is configured as input pin using an external 4.7K Ohm pull-down resistor to ground. Default state therefore is low. When I ...
Tintenfisch's user avatar
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Do ESP32 GPIO pins with roles such as 'BOOT' affect my program?

I am working with an ESP32-C-DeVKitC-02. I do flash it via USB: There are pins with roles such as LOG or BOOT. Will they affect ...
Tintenfisch's user avatar
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4 answers
172 views

What current can an FS32K148UJT0VLQT GPIO source?

I am using an FS32K148UJT0VLQT in my design. I was trying to see the maximum current the GPIO can source. My board is working at 5V. The DC electrical specifications at 5V is given below. Minimum ...
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UART GPIO Expanders

I'm looking for a GPIO expander with UART interface, but I can't find a single IC. I know that this is not the place to ask for product recommendations, but I wonder why there are hundreds of GPIO ...
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How to read the output of a slot-type photomicrosensor with a MCU?

I am trying to use an optocoupler as an edge sensor (to restrict motion). I am using these ones: https://www.aliexpress.com/item/1005001921249243.html Or same diagram here: https://assets.omron.eu/...
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GPIO trigger and correct pull-up/-down resistors? Internal pullup deviates from recommended value

I have these devices: Sensor Keyence FS-N41P Camera Flir Blackfly S Controller Teknic Clearcore The sensor triggers the camera and the controller. The controller supplies 24V to the sensor. This is ...
Martin Henne's user avatar
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Max reverse INPUT voltag/current for gpio set to OUTPUT

What would happen to a gpio pin set as high output if the pin already see a voltage higher than the MCU's voltage? Lets say 3.3V vs 3.4V I will probably solve this with a diode and using one extra ...
ISbit's user avatar
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Script Implementation of SN74HC165NSR

I have a PCB connected to my Raspberry Pi via its PiSound Header. It has 7 SN74HC165NSR shift registers. I'm trying to write a basic script that can read the ON / OFF state of the switches on the PCB ...
Jelani Thompson's user avatar
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Receive i2S data to RP2040, PIO and DMA from MEMS microphone (SPH0645LM4H-B)

It pretty much seem to work. I have in the PIO been able to generate the clock and word select and the microphone is sending data continuously which can be verified with a logic analyser. (maybe it ...
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Switching power and controlling RPi GPIO pins with a single rocker switch

I have a 12V amplifier board with the sound source being a raspberry pi. I'd like to have a single rocker on/off switch that both turns off power to the board, as well as connect to the RPi GPIO pins ...
youcloudsofdoom's user avatar
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Trying to drive a I2S MEMS microhpone (SPH0645LM4H) using RP2040 PIO but timing seems bad and I dont get any audio back

So I want to connecte an i2s MEMS microhpone to a RP2040. I have made a PIO program that looks like this: ...
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Clarification about leakage current in IC

Datasheets usually specific pin leakage current for digital inputs in the Electrical Characteristics, which is generally in microamperes (µA) range. I understood from different SE posts that the ...
LoveEnigma's user avatar
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GPIO and LDO voltage slightly increases when other GPIO enables load

I have a circuit in that GPIO_1 (yellow trace) is generating repeating signals to control an NMOS and GPIO_2 (green trace) is controlling an LED driver (buck DC/DC) load via an NMOS switch. When a ...
Travis Su's user avatar
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GPIO voltage drop

I have the following problem. I have a 3 V line that comes from an electronic drums controller that goes into a pedal through a mono cable (TS). The tip has +3 V and the sleeve is GND 0 V. When I ...
Victor Corchez's user avatar
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2 answers
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Can I use GPIO logic level converters as tiny low-current solid state relays?

In order to use a GPIO pin to drive a 180 mA mini water pump, the GPIO pin needs to switch a MOSFET or an Optocoupler because it can't safely do 180 mA. I want to run 16 low-current pumps from 16 GPIO ...
Redsandro's user avatar
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PIC32 VUSB3V3 must be externally powered?

I use a PIC32 and I want to use RB11. That's a USB pin but can be used as GPIO. The datasheet specifies in 18.4 page 180: For non-USB operation with RB11 and/or RB10 as GPIOs, the USB module must be ...
DamanZ4's user avatar
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STM32 square wave fluctuating

I'm outputting a square wave from a GPIO pin but the signal shows that the time it is low and the time it is high are changing even though they should be the same. How do I fix this? Note that the ...
epicMan123's user avatar
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Does my GPIO Expander have a floating pin? [Button and pull-up resistor]

I am using GPIO expanders (MCP23017) for an array of buttons. Each button is connected between GND and an input pin of the expander. I've enabled the 100k internal pull-up resistor on the MCP23017 (...
Nate.Olson's user avatar
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GPIO Alternate Function GD32

I am trying to understand how alternate functions work at the register level for the GD32 microcontroller. For example, in the case of the GD32F103, there are several alternate functions available for ...
Andr's user avatar
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What port is this, and can I create a cable for it?

I have a Elo Backpack 4 and I want to make use of the GPIO port to open a cash drawer via RJ11. There is information regarding the GPIO in the Backpack user guide. It mentions that this cable can be ...
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DS90UB926QSQNOPB Power down control using Microcontroller GPIO

I am using DS90UB926QSQNOPB in my design.This is a 24-Bit Color FPD-Link III Deserializer With Bidirectional Control Channel.I have a question regarding Power-down Mode Input Pin. Below is the ...
Confused's user avatar
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Detecting 16 V AC with a GPIO

My project involves detecting a ringing doorbell. The doorbell circuit is 16 V AC and I want a low-voltage binary signal from it. The obvious way to me is to transform that electrical signal until ...
Jonah's user avatar
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4 answers
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If making your own microcontroller board, what types of pins may be used as GPIO pins?

If were to make my own microcontroller board, something similar to the Texas Instrument MSP430 Launchpads, what types of pins can I use for the GPIO male header pins to solder to the board? Do they ...
keikaku's user avatar
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Can I control any transistor (NPN/PNP) using a GPIO pin of my MCU? Is my schematic correct?

Can I control any transistor (NPN/PNP) using a GPIO pin of my MCU? Is my above schematic correct? EDIT 15/02/24: A REVISED SCHEMATIC, AFTER THE ANSWERS Is the revised schematic below now correct? My ...
Bala's user avatar
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What guarantees are there on when GPIO states are read and written?

I'm fairly new to electronics, coming from software engineering, and it's not clear to me when GPIO states are set or read in microcontrollers relative to a clock pulse. If on cycle n, I toggle a GPIO,...
Julien BERNARD's user avatar
2 votes
2 answers
229 views

How big a pull-up resistor is needed to pull up an internally pulled-down GPIO (ESP32-C6)?

I'm feeding a BCD diode matrix of switches with Vcc at 3.3 V and running the BCD outputs into GPIOs on the ESP32-C6. The plan is to set each GPIO input to internal pull-down so I can pull it up ...
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What is the fewest number of GPIOs to read 5 push-buttons?

This answer gives a good explanation of how to use a keypad matrix to minimize GPIO usage by scanning rows and columns to find a button press when an interrupt triggers. This scales very nicely for ...
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Control chip with a GPIO pin using a transistor and a push button switch

I need some help regarding a small circuit that I'm currently working on. I have a microcontroller (ESP32) that I want to use to control a chip with a GPIO pin of my ESP32 as output, and at the same ...
Reicken Back's user avatar
1 vote
1 answer
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Voltage divider with serial resistor connected to BOOT1 pin from STM32F10X microcontroller

I was viewing a circuit in a schematics that is given to me. I found this voltage divider with a resistor connected to the BOOT1 pin from a microcontroller: NOTE: BOOT1 is connected to the BOOT1 ...
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Can I drive LVCMOS12 on Xilinx Artix-7 at 100 Mbps?

I'm currently planning a setup as shown below, where I need to operate the GPIO on my chip at a data rate of 100 Mbps. My biggest concern is whether it is a feasible to drive LVCMOS12 on Xilinx Artix-...
Emm386's user avatar
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Can a GPIO drive MOSFET gates in parallel?

I'm trying to make a circuit that tests if there is any connection in the little box between the transistors. If there is connection on all the boxes, I'll be able to read something out on the ADC. ...
user362085's user avatar
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Is this the correct isolated circuit to control a relay output from a Raspberry Pi GPIO?

I am making a circuit for an optically isolated relay output controlled by a Raspberry Pi GPIO pin. I am not sure if this is the correct way of doing it. Can someone please help me out on this? Edit: ...
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Hardware, architecture needed to be able to send bit-level messages on a CAN bus

I have a can bus with nodes and I need to be able to send low-level messages on this network, i.e. messages defined by ones and zeros and I also need such fine grained control so as to be able to ...
jgklsdjfgkldsfaSDF's user avatar
1 vote
1 answer
248 views

Can I use a different channel of a timer at the same time?

I am using AVR128A for a project. It comes with two 16-bit timers (Timer 1 and Timer 3) and two 8-bit timers (Timer 0 and 2). Timer 1 has two channels whereas Timer 3 has three. I have all the timers ...
RK Eshat's user avatar
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How do I simultaneously distribute a GPIO 3.3V logic signal to a batch of identical devices with 1.8V input

I'm asking how to distribute a 3.3V GPIO output logic signal onto many IDENTICAL devices that have 1.8V input. The first device is no more than 4m from the MCU. Each device is tapped (wired in ...
torpedo51's user avatar
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How to scale a GPIO control line to mitigate system impedance

I'm trying to build a circuit for a GPIO control line. Each device tapped into the line operates at 1.80v; the line is held at 1.65v HIGH. The GPIO output pulse profile is 1.000s @ HIGH 1.65v + 40ns @ ...
torpedo51's user avatar
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Three wire remote controller - wiring to two GPIO pins

My remote camera trigger has three wires (red, yellow, white). The white is shared, and the trigger can complete two different circuits by shorting it with either the red or the yellow cable. One of ...
Michael Murphy's user avatar
2 votes
2 answers
158 views

Detecting SCL/SDA ports

I am working with the EFR32MG24 Wireless SoC Family. There is a controller and multiple sensors with custom cables and connectors. For flexibility it would be desirable to connect the cable two ways, ...
billbillybill's user avatar
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Slave SPI not firing interrupt

I have 2 STM32F407 discovery boards for which I'm trying to setup a multi slave SPI bus. The first slave is working but the other one is making problems once I connect the second CLK input onto the ...
Michael's user avatar
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Internally connecting pins on microcontroller

I am working on generating passive LCD waveforms myself using a microcontroller, and am noticing that proper LCD driver hardware has only one set of resistor dividers for generating bias voltages and ...
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