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 ...

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Raspberry Pi B+ with relay: Lights change but relays don't click

I am using an 8 Relay module, bought from dx.com. It has no instruction manual... This board has 8 inputs (IN1,...,IN8) to control each relay, 1 VCC pin that requires 5V and 1 GND pin. I connected ...
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18 views

STM32F051R8: PWM timers don't work?

I'm working with MB1034B discovery board and STM32F051R8 microprocessor. I'm trying to output some PWM pulses using hardware timers. I use this tutorial (for STM32F4xx): ...
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40 views

STM32 F205VCT6: GPIO B Port 6 and 7 do not work?

I'm using the STM32 F205VCT6. I have a simple blinking LED program written in C++ with VisualGDB (and VS 2013 Community). It works fine for pins like A1 and E2, but it doesn't for B6 and B7, where I ...
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53 views

need for external i/o interfacing like in 8086 for latest processors

I am a student now currently learning about interfacing 8255 with 8086. For me the doubt is that, is there a need for external i/o interfacing like in 8086 for latest processors? what is GPIO ?
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56 views

More Current from GPIO

I'm working on a project that uses a GPIO port extender, but I need the ability to sink more current on the GPIO pins. There are 24 GPIO pins. Each pin can either be input or output. The pins ...
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2answers
153 views

Controlling 10 high power LED with a Raspberry Pi

I'm trying to figure out how to control 10 Luxeon Rebel LED (700mA) from a Raspberry Pi. I want to be able to turn them on and off from code, but I don't need to have two or more LEDs turned on at ...
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0answers
30 views

Explain to me how values are read with pullup resistors [duplicate]

In the above picutre, it seems to me as if when the switch is open, a voltage of VCC is on the input pin (i.e., voltage comes in through the resistor, to the input pin then back to GND through the ...
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2answers
221 views

STM32 Understanding GPIO Settings

In STM32 Standard Peripheral library, we need to configure the GPIO. But there are 3 functions which I not sure how to configure them; GPIO_InitStructure.GPIO_Speed GPIO_InitStructure.GPIO_OType ...
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77 views

How do I connect a photodiode to a GPIO?

I'm trying to read serial data emitted through an IR led with a Raspberry Pi using an IR photodiode, but I'm not sure about the correct way to hook it up. Unfortunately I don't have a part number for ...
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1answer
66 views

using transistor to switch 3v from 2

i need to use a GPIO pin to test whether an LED is on/off. the LED only has 2v power which is not enough for my digital input (3.3v) so i would like to use a transistor to amplify the voltage from 2v ...
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2answers
75 views

Solenoid Valve - Transistor or Relay?

bit of an amateur looking for some advice. I looked at the other question concerning my problem but i didn't find what i was looking for. I need to switch ON and OFF a solenoid valve using my RPI. I ...
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1answer
54 views

problem with LED matrix and raspberry pi

I have a raspberry pi model B+ , and an 8x8 LED matrix(single colored) , so I connected 8 GPIO pins to the 8 row pins of the matrix and another 8 GPIO pins to the 8 colomn pins. Note that I am pretty ...
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2answers
192 views

AVR and STM32 ARM GPIOs state when IC is unpowered

I'd like to make a device combined two controllers: ATMega64 I already familiar with and ARM Cortex-M0 STM32F051 I'd like to be familiar with. I'd like to directly connect GPIOs of two controllers. I ...
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2answers
101 views

Is it possible to use SIM900 GPIO to control relays without using external MCU?

From the product manual / reference guide it looks like SIM900 / SIM900A is already equipped with 12 GPIOs. But could not find information on how to use these GPIOs to control relays directly, ...
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2answers
85 views

GPIO Input Circuit

This is the first time I've done something like this so I'll be happy to get a detailed explanation. First of all could you explain how this circuit works? Second, I have this PCB that I want to ...
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1answer
96 views

Connecting pins of Raspberry Pi GPIO in series in order to turn up the voltage

It's unorthodox and probably not recommended by anyone but, for my project of driving a relay only with scrap parts and on the cheap, I managed to get a 12v relay, but, the GPIO ports on the RPi only ...
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1answer
57 views

How to remove GPIO ribbon from raspberry pi

This is basically it. I got my new raspberry pi and I got a GPIO ribbon to connect it from the raspberry's GPIO's to a breadboard. Now I am trying to remove the ribbon from the raspberry by just ...
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0answers
44 views

STM23 and TLK105 Ethernet acts strange

I am conntecting STM32F107 and TLK105 from Texas Instruments and it works fine most of the time. The problem is a very strange behavior such as: - TLK software reset is not done correctly - Reading ...
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40 views

Controlling Raspberry Pi GPIO using Javascript [closed]

I am familiarizing myself with the GPIO pins on the Raspberry pi and was wondering what the easiest way to control them would be using HTML and javascript over a webpage. My intent is to have a button ...
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81 views

MIPI interface and GPIO differences

There is a possibility to do a connection between an IC that communicate with MIPI interface, with GPIOs of an MCU that doesn't have MIPI inteface? How?
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18 views

Murata SMD External Drive Pizeo from SBC

I would like to drive a Murata SMD from a SBC (Arietta G25) with a 3.3v Logic PWM output. I've looked through the Murata catalog and seen the examples however I'm still confused as to how the circuit ...
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4answers
118 views

Low component count isolated contact closure without power on the remote side

Other answers here show a common way to allow a microcontroller to cause a contact closure (button press) within another device in an isolated fashion: use an optoisolator. I have the reverse ...
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2answers
55 views

switch that closes when power is on

I'm currently working on a project that makes a device "IoT-ready". So im looking for a switch, which got two inputs and two outputs. When I close the circuit on the one side, it should close it on ...
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54 views

Programmatically short GPIO pins Raspberry Pi

For a hobby I'm working on a project connecting a RF remote to the raspberry pi. When I press a button, pin 13 and 14 are shorted on the MCU. When I put a jumper cable between the pins, the remote ...
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1answer
31 views

Will GPIO still be available when connecting a BoosterPack on any Launchpad?

I had this question in mind while exploring the BoosterPacks for the TI Tiva C series launchpads. Let's say you connected KenTec display to the board, you still have access to the female headers on ...
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1answer
66 views

The program doesn't work correctly when I toggle the pin via Set and Reset register

I have two program to do the same task. the both should toggle GPIOB0. the first program is this: ...
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2answers
213 views

Can someone explain to me programming logic behind multiplexing a LED segment display?

I am new to programming embedded systems, so any help is appreciated with my question. My task is to program (in C) a timer that counts up on a 7 segment common cathode display such that it will read ...
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1answer
57 views

Microcontroller GPIO input voltage limit

I was looking at a datasheet for a microcontroller and noticed that, under its section for GPIO input voltage (p.14), there is no listed maximum for the high input, only a minimum. Does this indicate ...
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1answer
60 views

Help needed driving an old PIC programmer from Raspberry Pi GPIO

I have been trying to use a Raspberry Pi's GPIO pins to drive an old PIC programmer board that used to have a parallel port connection before I started messing about with it. You can see from the ...
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1answer
74 views

Why is P9_14 GPIO input using Adafruit's library giving me -1227689624 on my BeagleBone Black?

I know I should really be writing my own GPIO libraries so I know how they work and can fix them when they break, but for now I am following a simple tutorial using Adafruit's GPIO library, which I ...
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1answer
115 views

Protection GPIO of controller

Today I had a luck to kill my STM32F3discovery through connecting pin to +18V and this trouble made me think about protection from such situation in the future. I've found this protection of inputs ...
6
votes
4answers
1k views

What is the function of a diode connected to a GPIO?

I'm reading a schematic (done by a former employee) with a microcontroller, and I came across this circuit: What is the function of D1? Also, I think that R2 isn't necessary, because the control ...
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0answers
63 views

How to determine a Signal Generator's Marker (Event) output delay?

I am using an Agilent N5182B Signal Generator for modulating a 2-FSK waveform on a 160MHz RF carrier. For that, I am using a baseband waveform (I/Q mode), generated by a Matlab FSK modulator script. ...
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3answers
187 views

What are the mechanisms at work in a pull-up or pull-down resistor circuits with a push-buttons and a GPIO?

I have a question regarding the GPIO (from a Arduino board for example). How does it work exactly when you use it as an input pin? What are the mechanisms at work when you use it in a pull-up and ...
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1answer
79 views

MCP2200 - which GPIOs for DTR, DCD, DSR and RI?

Due to the recent controversy surrounding FTDI, I'm looking for a replacement for future designs. I'm looking very hard at the MCP2200. The only thing I can't figure out is that they have several GPIO ...
0
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1answer
91 views

How could this GPIO-controlled LED status blinker be improved?

I'm building a simple circuit to drive an LED status indicator in a project built around a RPi. The circuit takes its power from the same source as the RPi and is connected to one of the RPi GPIO ...
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1answer
157 views

Using GPIO mode in SIM908

I'm working on a SIM908 module using GPIO mode (my rx pin contact is lost when soldering). I have interfaced it with a PIC16F73 and while using GPIO mode I'm not getting any response. I have included ...
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0answers
147 views

How can I use the OSC2 pin as normal IO on a pic32mx150f128b?

Everything else works well, the CPU runs at 40 MHz, UART works, GPIO works; the OSC1 pin works as GPIO as well. But I cannot use OSC2 as GPIO. I am using the Fast RC oscillator with divide-by-N and ...
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0answers
61 views

Remotely Toggle Relay

A while back I decided I wanted to get into electronics, after which I bought a number of components to get me started, along with the Raspberry Pi and breadboard I already had. I am now wanting to do ...
0
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1answer
70 views

Connecting GPIO and SPI signals via cable

There is a requirement in one of our systems to transfer signals from one board to another board in the same system. The signals are GPIOs and SPI lines from I.MX6 processor and it is in 3.3V ...
0
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2answers
125 views

Connect an ATmega328 to a Raspberry Pi

I've been stuck on this problem for a couple of months now and haven't had much luck finding the exact information that I need. So, I'm currently working on a project to make a handheld raspberry pi, ...
0
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1answer
44 views

Can features like ADC and PWM on a pin be considered as functions/configurations of a GPIO?

this is more or less a question about wording. I am designing an API and need to figure out whether or not the namespace name used is correct or needs to be refactored. The namespace is called GPIO ...
2
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3answers
274 views

Is there a GPIO IC that has a parallel interface?

Sorry if this is an obvious question, I come from a software background and don't know the names for a lot of components. I am designing some custom hardware based around a W65C02S processor (a modern ...
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2answers
142 views

Can a digital input having internal pull up resistor drive a load?

simulate this circuit – Schematic created using CircuitLab I am working on MC56F8006 DSC . On power up or reset the default state of all GPIOs is inputs with internal pullups enabled. I ...
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2answers
135 views

GPIO interrupts in alternate mode

Are the interrupts in GPIO module triggered (high to low edge, low to high edge, low level or high level) when GPIO is operating in alternate mode functionality?
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1answer
314 views

Can I loop two GPIO pins on an Arduino/ATmega328?

I'm playing around with some wheel encoder sensors and an Arduino. The sensor needs a bit of debouncing, so that got me wondering how the microcontroller core is seeing the input. That is, what does ...
0
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1answer
148 views

GPIO Pin configurations [duplicate]

I went through the data sheet of STM32F4 and found the pin configuration of GPIOs. I dont understand the difference between these configurations. • Input floating • Input pull-up • Input-pull-down • ...
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73 views

Spurious interrupts using switches on a Raspberry Pi

I have two switches connected to GPIO pins on a raspberry pi. One side of each switch is wired to +3.3v. The other side is connected to an input pin via a 330 Ohm resistor, and each input pin has a ...
1
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1answer
169 views

Two or more different regulators connected to one battery

I want to make batteries provide power to both a micro controller (Raspberry Pi) and a 4x4 LED matrix. A simple circuit diagram is shown below. (only one LED is drawn in the fig. But regard it as LEDs ...
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0answers
82 views

Parallel Write On External Clock on STM32

I am using 8 GPIO pins on an STM32F407 for a parallel write to an external device (FT232H). The parallel write is synchronous, ie. I have to synchronize my data to a clock provided. According to the ...