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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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BeagleBone Black Driving NFETs w/GPIO

In short, I want to drive some NFETs directly from some of the BBB's GPIO. 3 of the NFETs will pass 1-3 Amps of D-S current and 1 NFET will pass <1 Amp from the D-S. As you may know the BBB's ...
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How to choose UART maximum output speed?

When I open up a project in STM32CubeMX and configure a UART, there's a Maximum output speed configuration (under GPIO Settings) that defaults to Very High. The options are: Low Medium High Very High ...
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Reduce wake-up noise on ARM CM3

I need some help exploring a solution. I have an ARM Cortex M3 MCU, which has low-power sleep mode implemented. Wake-up sources are any GPIO pin, or an RTC alarm. A terminal is connected to UART-0 ...
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ESP32: Using SENSOR_VP as GPIO

According to the ESP32 Hardware Design Guidelines, in section 2.1.6, they said: If SENSOR_VP and SENSOR_VN are used as GPIOs, while ADC is supported by other pins in the circuit design, users ...
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Calculate transistor collector and base resistors values for driving LED with GPIO

I try to learn how to use a transistor and how to calculate the necessary resistances. Here's what I calculate for the moment. I do not know at all if I left properly and if my equations are good. I ...
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How to implement multiple functions on single push button

I am using a STM32 Nucleo MCU and trying to pull a multi-function single-button method. I need a way to implement this form of functionality for a single push-button: Push 1: function 1 Push 2: ...
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48 views

Using the GPIOs of an STM32 Discovery board

I would like to start learning how to program an STM32, because of this I bought the STM32L152C Discovery board. It's a very nice board, full of goodies, but I would like to use just part of them: ...
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59 views

Microcontrollers (STM32) and GPIO with momentary buttons

I have six momentary buttons and an STM32 Discovery board. I want to check the button presses. As far as I understand, I create a continuous loop that will check each GPIO consecutively. (I am aware ...
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28 views

Access Trinket m0 USB through GPIO pins [closed]

I want to solder a USB A connector to my Trinket m0 instead of using an adaptor cable to plug into my PC. Can I access Trinket m0 USB through GPIO pins? I have looked at the description of the ...
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Can I use one pin as I2C clock or data AND as GPIO?

It happened to be that I run out of pins on ATmega48PA. So I have a pull-down buttons on the pins dedicated for I2C: And now I need to add I2C bus to this device with as much backward compatibility ...
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GPIO output impedance from Microcontroller Datasheet

I am building an application around the Texas Instruments TUSB3210 USB Microcontroller (Now obsolete, not on market) I referred to this datasheet to try and estimate the maximum current that can be ...
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Prevent spurious triggering of NodeMCU GPIOs

I designed a simple circuit to control a relay with a NodeMCU micro controller. The NodeMCU polls a remote web service via a simple API and pulls high or low the D1 GPIO according to what it's posted ...
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31 views

Low current RPi GPIO inverter

What is the lowest current way of inverting the output from a GPIO pin? I have a solar board that has an add-on that can turn a USB port power off if a LiPO gets below 3.3v. The problem is, they ...
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50 views

Raspberry Pi GPIO output not working with MOSFET N Channel Switch

My circuit is below - I'm trying to switch a solenoid valve using a Raspberry Pi. I have tested the MOSFET switch with the dedicated 3v3 pin on the Raspberry Pi, and have also tested that GPIO pin ...
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2answers
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Addressing 45 Inputs Down to 6 pin Output

I'm looking for a chip which could minimize ~45 button inputs down to an 6 pin input for use with Raspberry Pi. I know this is a simple problem and it has likely been solved before, but as an ...
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1answer
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Clock gating on Tiva Launchpad

I am working on a Tiva launchpad board and want to use the GPIO. I have successfully enabled the clock on PORTF using this line of code: SYSCTL_RCGCGPIO_R = 0x20U; ...
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77 views

Control GPIO pins using USB [closed]

What is the easiest way to make a device that can control GPIO pins using USB? Can I make a device similar to this on my own without any special hardware?
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Reasons for having MCU pin-states default to pull-up/down out of reset

On many MCUs, pin-states default to tri-stated (a.k.a. analog inputs) when the MCU resets so as to not affect the circuits they are connected to until software configures the pins. The tri-stated ...
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MSP getting powered up from GPIO

On a demo board I have, USB 5V rail is connected via a resistor divider to one of the GPIO's of MSP. MSP itself is powered from PCIE 3v3AUX rail. In one of the cases when the board is not connected ...
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1answer
92 views

Breakpoint Alters PIO Interrupt Behavior - ATSAMV71

So I'm baffled by this... I'm working with an ARMv7-M microcontroller and GCC compiler, debugging some code where I'm trying to enable an interrupt. I'm trying to do the following: enable an ...
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1answer
129 views

How to convert a 3.3V signal to 5V for a Mosfet gate

Based on the question 4-5-v-on-gate-of-mosfet-while-switch-open I ask this more generic question. Main project: I want to create a 16x8 (or so) multiplexed LED circuit Sub project: Creating a 2x2 LED ...
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Multiple inputs for driving a reset (RST) pin

I have an active high reset (RST) pin that is connected to a push-pull output. I am trying to connect another input to this RST pin, but this input is unable to drive the RST line high. Is this not ...
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STM32F4 Fewer Pin Mapping possibilities for ADC inputs

For STM32F405 100pin package, its datasheet page 39 and ref. manual page 388 as well as CubeMX shows that there are 3 ADCs each share 16-channels as shown in following images. Although it is not ...
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TVS diode selection for 3.3 V GPIO

Please refer to my project architecture in the image below: Power supply is isolated flyback smps type. GND is not connected to Earth or Neutral of 220 VAC. All parts of circuit are powered up with ...
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How to control single 12V LED with 3,3v GPIO? [duplicate]

Heyo! I need to control single 12V LED using Raspberry's GPIO To be more exact, I need to connect 12V LED & push button to 3.3v GPIO in order to control LED (on/off) and read button push events. ...
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61 views

Protection against ESD/EFT/Surges

One of my project architectures looks like this: GPIO / 595 output / 12 VDC wire lengths will not exceed 25 cm. I have faced MCU lockup issues due to EFT in the past and want to make sure this ...
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Unable to Read GPIO on Atmel SAM4L

I can't believe that this isn't working for me. It should be straightforward, but I've spent the afternoon on it & can't see where I'm going wrong. Hopefully someone will see my obvious mistake. ...
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1answer
51 views

ST-LINK and PA13,14 Pins on STM32F407

If I use PA13,14 pins for flashing my MCU via ST-LINK programmer then can I also use these pins as GPIO in the same circuit? Will that not disturb the ST-Link if some analog or digital circuit is ...
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1answer
136 views

5V Current Transducer to 3.3V Analog GPIO Input

I am trying to find 3.3V variant of the 5V Current Transducer LTS_25-NP but so far no success. Is it possible to interface this 5V analog output to 3.3V STM32F407 analog input GPIOs? Edit: I want to ...
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1answer
148 views

NRST pin of unpowered STLINK V2

I am using the STLINK from a Nucleo board in order to flash and debug a STM32F7 MCU on a custom board. Everything works fine except when STLINK is connected to my custom board AND unpowered. Indeed, ...
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134 views

Interfacing GPIO 3.3V to 74HC04 5V

Will it be safe if I connect STM32F407 GPIO outputs (Vdd=3.3V) to 74HC04 hex Inverter inputs (Vdd=5V)? What is the best recommended method to add an inverter at the output of STM32F407 MCU? edit: ...
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1answer
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GPIO Configured as Input OR Output

Is it possible to identify looking at the schematics whether a GPIO pin is configured as Input or Output pin for the case in following image? PIN93 and PIN94 of a MCU are connected directly with ...
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1answer
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How can I check if an IO pin is dead?

I've been playing around with I2C for a couple days now with a DE10-Nano dev board: I'm implementing an I2C master in CLaSH so that I can talk to the HDMI encoder chip, but for now I'm talking to an ...
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41 views

Limiting the current into Raspberry Pi GPIO pin

I have a dc dc regulator which can output .35A Current at 3.3V. I just need to check that the voltage it is producing is 3.3V by connecting it's output into one of the GPIO pins of Pi. So i was ...
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44 views

low voltage pin in Keil (ARM) debuging?

I am going to work with one TFT LCD 2'8 (ILI9325 Driver) with STM32F103RE ARM MCU. So I have one example program in Mikroc for ARM ( Microelectronica Co), which is working good, you could download ...
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Presence of voltage in Mega+Ramps GPIO pin

I am using Arduino Mega + RAMSP 1.4 with Marlin firmware to control my machine(not exactly a 3d printer). Marlin has gcode M42 P20 S255 ==> Turn on 20 the pin of ...
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Is it possible to get the full spectrum of a RGB diode (3 prong input) through 1 GPIO pin?

I apologize if this question is not well formed. I am an amateur in this field. I have the requirement to independently control a plurality of RGB diodes from a single microcontroller. Each diode has ...
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3answers
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How to use a transistor to drive strings of LEDs from GPIO pins?

This is similar to How to drive a 20mA LED From a 4mA max GPIO Pin except that I need a little more hand-holding in order to understand what is happening. For background, I'm a software engineer and ...
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1answer
71 views

How to test my GPIO code?

Should I be asking this on Hardware Recommendations? That is – do I need some sort of test device? Or, hopefully, I can just my laptop … I am developing a vending machine controller, as a hobby ...
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1answer
35 views

Trouble with SO on MCP23S18 spi gpio expander

I am unable to get a signal out of the slave out (SO) line of an MCP23S18 For those not familiar it is a slave SPI gpio expander. Clocking in 32 bits, as it goes 16 bits set up, 8 bit opcode, 8 bit ...
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1answer
69 views

Controlling the brightness of LED panel via GPIO pins

I'm trying to control an LED panel like the one in this link. I notice it comes with an LED driver. But what I'm wanting to do is to be able to control the brightness of this light through the GPIO ...
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1answer
48 views

Controlling the power supply of a bluetooth module via GPIO and a transistor

I want to be able to turn a Bluetooth module on and off via a GPIO pin of a microcontroller. My first approach to realize this with a transistor is shown below. Is this approach correct? If not, how ...
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1answer
83 views

GPIO connected as open-drain to opto-isolator's cathode

When connecting GPIO output pins (RPi, uC, ...) to an opto-isolator, the classical way I know is the following (at least I understand that it can roughly be depicted like that): simulate this circuit ...
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1answer
42 views

MCP23S17 Interrupt Issue

I am having issues with interrupt setup on MCP23S17. Not able to set up the INTB line properly. I have an external 10K pull up resistor connected to the line and 3 input buttons connected to GPB0 - ...
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1answer
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Connecting multiple Net Labels to same Net Wire

I am using Altium Designer 17. My schematics is Hierarchical and divided into multiple sheets. Few sheets have microprocessor ...
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1answer
70 views

GPIO input state with undefined voltage

I am using PIC32MX350 series controller, on one GPIO , that is defined as input , and input that pin goes form one SMPS (PN : - PSC35 , IO Name :- AC out). Since SMPS IO is open drain we add a pull up ...
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Reading GPIO configuration (Cortex M4 ATSAME54)

I'm writing some diagnostics for a Cortex-M4 -- in this case an ATSAME54. I'd like to be able to read the configuration of individual GPIO pins, namely: bool level enum gpio_direction direction [IN, ...
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86 views

OSError: [Errno 121] Remote I/O error or pigpio.error: 'I2C read failed' on MPU6050

So I use MPU6050 to get acceleration from stepper motor linear rail movement(steper motor working in thread, I use pigpio for the motor) by make the MPU6050 can work on threading and it can show data ...
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1answer
61 views

Receive same GPIO input signal on multiple raspberry's from one source

I'm having 7 raspberry Pi's 3 connected to 7 screens, running an python 2.7 app to download different images from google drive, every raspberry has different images. Geeqie is displaying those images ...
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1answer
67 views

Sudden raspbery pi power cut or random long delay when running stepper motor using pigpiod

So I wrote another program that can run stepper motor nema 34 using leadshine DM860 driver and this is the example of my code: ...