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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34 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
120 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
43 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
33 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
38 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
94 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 ...
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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
50 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
118 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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0answers
35 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 ...
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1answer
71 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
95 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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88 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
45 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 ...
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1answer
43 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 ...
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2answers
91 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, ...
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1answer
40 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 ...
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3answers
218 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
110 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
126 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
227 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 ...
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1answer
106 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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0answers
66 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 ...
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1answer
152 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
65 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 ...
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3answers
150 views

How to wire 12 cameras to trigger simultaneously

In the documentation of a camera it says: "To activate a GPI trigger, momentarily short pin 2 to 1." But I have 12 cameras and I want to trigger 12 cameras at the same time, how should the ...
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1answer
44 views

Configure GPIO pin for infrared interface (IRTIM) of STM32F030x4/x6/x8

I have a problem for use infrared interface (IRTIM) of my MCU. When I saw in Reference manual I could find this: Now, when I search for find GPIOx_AFRx register, I cannot find this register in ...
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1answer
39 views

SX1509 Analog to Digital Converter?

I purchased this product: https://www.sparkfun.com/products/11502 I've wired it up to 5 membrane pressure sensors which provide variable resistance depending on the pressure exerted. However I'm not ...
0
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1answer
62 views

pwm or gpio for pled display on beagle bone? [closed]

Wondering which adafruit bbio library i should use. I know nothing. My sense is that GPIO will be simpler to communicate the display info to the screen. The screen is a 128x32 adafruit pled
5
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3answers
159 views

Dump Flash Memory through a single GPIO pin

I'm working with Infineon's XMC4500 Relax Kit and I'm trying to extract the firmware through a single GPIO pin. My very naive idea is to dump one bit at a time through the GPIO pin and somehow ...
0
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1answer
117 views

How does a stm32f chip set its GPIO speed? (hardware, not register setting)

The speed of GPIO of a stm32 chip is set by register of OSPEEDR. It shows: 00: Low speed 01: Medium speed 10: Fast speed (50MHz in library) 11: High speed (100MHz in library) My guess is ...
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0answers
56 views

Communications between ArduPilot Mega and BeagleBoneBlack

I am trying to send complex control commands from BeagleBoneBlack(BBB) to ArduPilot Mega(APM) 2.5, such as loitering and acquire GPS location. The documentation on APM is somewhat dated and vague. I ...
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1answer
268 views

Beaglebone Black GPIO pins not working

I plugged a simple LED circuit that I've tested elsewhere into the Sys_5V (pin p9_7) and GND (pin p9_1). Then I tried p9_23 GPIO and set it to digital high it didn't work either. Why also: Sys_5V ...
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0answers
163 views

GPIO in device tree

My board has 3 GPIOs, namely gpio0, gpio1 and gpio2. Each of them have 32 pins. They were ...
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2answers
102 views

Would driving transformer with MCU's GPIO cause durability issue?

For making isolated power supply, I would like to drive a transformer with two GPIO's of a MCU. The center tab of the primary will be connected to Vcc. And each end of the primary will be toggled ...
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4answers
180 views

How to drive LED when sinking current to MCU?

Hopefully a simple one. Should I always control by writing to the GPIO digital output? Or should I always leave it low and then tri-state the output? LED turns on when MCU pin sinks current: In ...
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2answers
545 views

How to create USB toggle switch controled by GPIO

I have Raspberry Pi setup as NAS. The storage is external HDD powered through USB. I would like to encase this whole thing in some nice box and still be able to easily use the HDD, without ...
0
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3answers
614 views

Understanding GPIO analog and digital

I'm trying to understand GPIO, and have read a bunch of different blog posts and I think I'm close to getting it, but still struggling with a few things. I've seen a few reference to GPIO only being ...
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3answers
654 views

Proper usage of a MOSFET to control USB

On the RaspberryPi.SE it was suggested that one can use MOSFET BS170 to switch a USB device on and off by a GPIO pin (3.3V). I need to get 500mA to power a GSM dongle; the voltage drop should ...
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1answer
161 views

Is it possible to get input from a 10x10 grid of switches using an arduino board? (Uno, Mega, etc.)

I'm more of a software guy but I'm working on a prototype of a game that will use a pressure sensitive 10 by 10 grid. This will require 100 switches just for the grid. The closest I've found to off ...
1
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3answers
365 views

Drawbacks of using single-ended communication over differential pairs

I recently bought a ZYBO FPGA board only to find out that there are exactly six regular single-ended GPIO lines wired to the FPGA. In contrast to that, 18 differential lines are available. The board's ...
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0answers
135 views

Xilinx Spartan3-E FPGA input impedance and input leakage current for the GPIO pins

I am trying to use one of SPARTAN3-E FPGA GPIO pin as an input to ADC. I want to know the input impedance and the leakage current for GPIO? Should I just connect my circuit's Vout to GPIO pin or ...
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1answer
51 views

Interfacing GPIO pins between a uC and RS-485 tranceiver

uC: EM357 datasheet RS-485 IC: sp3078e datasheet Two input pins on the sp3078e need to go high at the same time when I'm sending bytes. I'm using a single output pin on the EM357 to drive both of ...
3
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2answers
452 views

Cannot get a digital square wave on oscilloscope from the GPIO of the Raspberry Pi?

ENVIRONMENT: Running "Raspbian" on Model_B Raspberry Pi (Revision 2) w/ ribbon expanding the GPIO out onto a Breadboard as shown in the following image. SETUP Here is a close up of the GPIO ...
4
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2answers
1k views

Does driving an microcontroller's GPIO when it is powered off weaken the chip?

We are using the LTC5800-IPM microcontroller in a project. The way our design is now, the IC's GPIO pins will sometimes be driven high (to 3.3V) or low when it is powered-off. Will this weaken the ...
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3answers
190 views

Does a clamping current specification under Absolute Maximum Ratings imply that less current is OK?

I have an application where I want many small signal relays driven by an I/O expander chip. In this case, I have selected the Microchip MCP23017 (Datasheet) as an I2C to GPIO expander. I have also ...
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0answers
148 views

MSP430 GPIO behaviour on power off

I have a simple circuit which contains an MSP430 connected to a DAC8551. I'm using PORT1 so have implemented a bit-banging approach instead of using the USCI module (bad, I know). I've noticed a ...
3
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1answer
409 views

GPIO on PIC16F887 not working

I've set the PIC16f887 on both external crystal 20MHZ and internal oscillator 4MHZ, neither of them ever worked with the following code: ...
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1answer
129 views

Use voltage regulator instead of zener to protect GPIO

I've read several articles about protecting 3.3v GPIOs from unregulated over voltage, all of which involve using a zener diode, a diode for reverse protection and resistors in some fashion. example 1 ...
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1answer
92 views

Frequency Sensitivity of GPIO Pins

When reading from a GPIO pin, at what frequency do the crests and troughs of a wave begin to blend together to the point that the CPU can no longer distinguish between them? I assume the answer ...