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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56 views

Working display connected by GPIO pins to microcontroller?

Would it be possible to add a normal HDMI port or a display to any microcontroller with the GPIO pins? (I didn't buy anything yet, I'm just getting information before I buy...) EDIT: Thanks for all ...
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0answers
19 views

ESP8266 using LOW-Level with GPIO0

as you know to put ESP8266 into bootmode GPIO0 should be connected to the ground. That works perfectly, but the problem I don't ...
0
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1answer
54 views

STM32F103 GPIO and wrong configurations

I have a few questions about gpio. First What if two push-pull pins with high level connected? My point of view is that there is no way for current and nothing bad will happen. And reading of pin ...
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0answers
63 views

controller pins issue during hot swapping

I am using CortexM3 controllers(LPC1769,1778) in my embedded applications. I terminated UART pins to the connectors with TTL level. If I am connecting or disconnecting the UART cable during power on ...
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1answer
107 views

Best way to control power with MCU gpio pin

This is my circuit. An MCU gpio pin should control the power of another IC. Because the component requires more current than the gpio pin can drive, an N-Channel MOSFET is used. This is IC has no ...
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0answers
15 views

Unable to upload lua code into the nodemcu

I am unable to upload lua code into the nodemcu, though AT commands work. I am following this instructable: VCC ----> 3.3V Power supply (Vout of LM1117) GND ----> Ground of power supply CH_PD ...
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1answer
17 views

What does short circuiting a RST front IO header do?

My motherboard has a connector to enable the use of a front panel RESET button: I would like to simulate the press of the button (equivalent to short circuiting the wires) by a Raspberry Pi, by ...
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1answer
63 views

Software SPI 3-wire read register

I currently try to read a register from an acceleration sensor (ADXL345). i try to simulate the SPI procedure with software. I wrote a readRegister function: ...
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1answer
36 views

Inconsistent GPIO values on Beaglebone Black running Debian

I'm trying to use GPIO on my Beaglebone Black, but I'm running into some behavior I don't understand. I have two pins (gpios 27 and 61) configured to input with ...
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1answer
33 views

can't figure out why dsPIC digital input is not working

Having trouble getting a basic digital input to work correctly. Just trying to use it as an additional condition for an LED flasher to work. Right now their example code works just fine but when I ...
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1answer
49 views

Problems reading GPIO states set between STM32F Discovery and Nucleo64 boards

I am currently having an issue setting up a communication protocol between an STM32F discovery board (using the latest HAL drivers) and a Nucleo64 board (using the same drivers). Essentially each ...
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1answer
67 views

How to use the Non Maskable Interrupt on SAM4S?

I'm trying to use the NMI on a SAM4S (Cortex M4), but I'm finding some hard time to make it work. The main objective is to jump to the NMI handler whenever the power is about to go down, so that I can ...
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2answers
92 views

Are most GPIOs on common MCU's merely 'sourcing' or also 'blocking'?

Granted most MCU's are configured such that to 'activate' a device on a logic high (take the simple case of an LED, or a relay or transistor for something higher power) the MCU is sourcing VCC and the ...
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2answers
66 views

NXP LPC GPIO Glitches on every power up. How to solve?

I've been using NXP LPC microcontrollers for some time. One problem that I've faced in several projects is that every time the MCU is powered and a GPIO is setup to LOW logic level and output, a ...
7
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3answers
747 views

What actually happens when we set direction on GPIOs in controllers ?

Generally, while working on GPIO pins of any controller/device, we set the directions for the GPIO pins. Let's say in LPC2148(ARM7 core) controller, we have IODIR to configure the direction of Pin. We ...
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0answers
28 views

How to set the limits of a Limiting Amplifier?

I want to use a limiting amplifier (LA) to prevent overdriving an input to a 3V3 GPIO, but I'm not sure how you go about setting those limits. I have an example of a 'typical circuit' which ...
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0answers
38 views

Interfacing Example for GT-511C3 Fingerprint Scanner and Raspberry PI 2 Model B

I want to know, how to connect GT-511C3 Fingerprint Scanner Hardware with Raspberry PI 2 Model B and will these connectors be good to achieve the same? and, I want to connect the scanner without ...
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0answers
15 views

photodiode recommendation for RPi 2B VLC [closed]

I'm going round in circles trying to find a suitable photodiode for my VLC project. I want to run it directly off my RPi 2B gpio and also feed into either a TIA or op amp to process a digital signal. ...
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0answers
22 views

understanding FPGA datasheet: access speed to io lines [duplicate]

I am looking for the right fpga chip for a project. Crucial is the speed at which the fpga can access the physical gpio lines of the chip in order to realize a parallel interface. As I could not find ...
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1answer
49 views

I2c between beaglebone black and STM32F4-discovery

I'm planning to connect my beaglebone black to stm32f4-discovery. The purpose is to test i2c library of beaglebone black written in c. But I'd like to check if I'd fry my boards. Would it be okay to ...
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3answers
94 views

What is the pin state during microcontroller flashing?

I know that upon reset most micros put pins into high-z state. Is this state preserved during microcontroller flashing? What precautions need to be taken if you are going to reprogram microcontroller ...
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2answers
41 views

Using Raspberry Pi GPIO for matrix switching

I'm working with a Raspberry Pi. I want to be able to connect any two of 7 pins together in a matrix fashion to control a device with a keypad input. This means I need to be able to short any of the 3 ...
0
votes
3answers
92 views

Wire microswitch so state can be read from Raspberry gpio

I'm trying to check whether a series of valves (described here Can I measure if current is on or off in cable with 24v DC (in a cheap way)) are open or not. Updated question to be more specific after ...
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2answers
61 views

Raspberry Pi: Do the electrons flow from the power pins or ground? [closed]

I'm rather new to this and am slightly confused about which direction the electrons actually flow. Using an LED with the knowledge that conventional current flows out of the cathode, and hence the ...
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1answer
30 views

Current drive capability

Can someone point out the mistake I'm making in reading this graph (which is from the ADI Blackfin 70x datasheet) If a driver was set high, to 1.8V, why would it be unable to source current? I'm ...
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3answers
106 views

What is the difference between Ground and Low?

What is the basic difference between sending a LOW signal vs GND to a circuit? What If I ground instead of sending LOW? Or similarly what is the difference between Vcc and HIGH?
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1answer
134 views

Output 48MHz system clock on a GPIO pin other than MCO pin on STM32F030

I want to output the max 48MHz clock signal of STM32F030 to drive another subcircuit. The problem is the chip STM32F030F4P6 (TSSOP-20 package) I prefer to use a GPIO because the MCU doesn't have the ...
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1answer
70 views

USB GPIO board stops responding after high voltage relay with load is switched on

I'm using Numato 16 GPIO board to switch relays on 8 Channel Relay Module. Until no 220V load is connected to the relay all works fine and I can switch on/off relay using Serial port command to GPIO ...
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1answer
163 views

SIM900 Power On/Off Circuit

I'm designing a board on which I'll connect a microcontroller with the SIM900 module. The recommended circuit for powering on the module (from the manufacturer datasheet) is given below. The module ...
1
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2answers
166 views

How can a GPIO logic to high amp/voltage logic adapter be built using multiple voltages? (5v, 12v, 24v)

I'm working on a project that requires making a fairly universal board (to work on different model machines). I need to hook up many pre existing motors and switches/sensors to the board that all ...
-1
votes
2answers
231 views

Modifying a thermostatic radiator valve for micro control

The photo below shows a electrical thermostat controller. The upper part is the motor with a gear. The motor has two wires attached. A red and a black one for the current. What this component does ...
0
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2answers
125 views

Transistor is always in saturated mode

I am new to electrical engineering so I am not even sure that I approach this problem correctly, so I will first give some background information. I have a RC car (LEGO dirt crusher 8369) that I want ...
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1answer
143 views

Microcontroller GPIO in audio circuits

I'm designing an analog synthesizer, which is controlled by an STM32 -microcontroller. In several parts of the circuit, I intend to use a GPIO pin to control switches in the circuit, and in two ...
0
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1answer
42 views

Minimum TTL 5.0V signal duration

I'm working on a little project in my physics lab. We would like to create a photon coincidence counter. We were thinking to use the Pi GPIO pin to monitor a couple of photo diode which produce a 15ns ...
1
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2answers
118 views

Driving a Sainsmart Relay using Raspberry Pi

I am actually a software engineer and not really familiar with wiring. I've been playing around with a Raspberry Pi Model B, and am looking to hook up a 2 PRONG Extension Cable to a Sainsmart 8 ...
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0answers
64 views

HDMI sleep/wake detect

My goal is to trigger some events using a microcontroller when my monitor attached via HDMI goes to sleep and wakes up. The standard HDMI interface has 'Hot plug detect' on pin 19, which is pulled ...
0
votes
1answer
93 views

How to generate UART interrupt for GPIOs?

I am using PIC32 and I have few inputs. I want a UART Tx Interrupt to fire whenever any input becomes HIGH. I have somehow manged to write code for UART tx and rx ...
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0answers
168 views

Reprogramming STM32 when using SWD pins as GPIO

I have prototyped a new design, but being short on pins I was forced to utilise the SWD pins as GPIO. I know when this is done it messes with the ability to program the chip as easily, giving the 'No ...
1
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2answers
117 views

Why won't my phototransistor interrupt my microcontroller?

I bought a couple of phototransistors. They all have one lead shorter than the other. I assume that, like normal diodes, this means that the longer lead goes to V+ and the short end goes to GND. I ...
1
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1answer
52 views

Error in making pins input in PIC32

I am trying to make some pins act as input in PIC32MX795F512L. I am doing like this ...
0
votes
1answer
60 views

FRDM K64-F GPIO Pins

I am building a small system to allow the FRDM K64-F to control some motors via a H-Bridge. My problem is I am sturggling to understand the documentation provided for the microcontroller. Can anyone ...
0
votes
0answers
57 views

Beagleboard Black all GPIOs are activated by a single GPIO

Earlier I was having a problem with BeagleBoard Black Rev C , which I discussed in the question below. GPIO.HIGH,LOW doesn't up LED Beagleboard I've found the real problem. Whenever I turn any ...
1
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1answer
71 views

reversed bias diode on GPIO

I was looking more into the GPIO pins of the ATmega328p and came across the simplified schematic of a I/O pin. The schematic includes two reversed biased diodes, one to the ground and one to the VCC. ...
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2answers
62 views

Reading data via GPIO

I have just learned GPIO and I've read a lot of in internet. As I understood GPIO port can be at one of two states: out and in. ...
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1answer
275 views

Pin value of a GPIO pin set as high impedance

I am using an STM32F4 discovery board and my intention is to set one of its GPIO pins at high impedance, which I have done as below: ...
0
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1answer
101 views

STM32 Timer Function Generator

I wonder how you can achieve that a GPIO pin accuratly toggles according to a certain pattern. This pattern is fully variable (no PWM) and is stored in memory. My conclusion of this is: The pin has ...
1
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3answers
159 views

Does this schematic with an old doorbell electromagnet look ok? And could it be improved?

I have a circuit which seems to work and I would just like someone to confirm that it looks ok and isn't going to damage a 3.3/5V system (Raspberry Pi). Also, if there are improvements / ...
1
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2answers
106 views

Question about this diagram [duplicate]

I am very much a software person and a rookie in electronics. I am trying to understand why do we need Diode D1 in the diagram explained in this post: ...
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2answers
95 views

Is there any compact relay (or any high current) chip for Raspberry PI?

I am fascinated how L293D makes it easy to control a DC motor. I wonder if there is any similar popular chip that controls a set of relays, so I don't have to use a bunch of transistors? PS. I am ...
1
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0answers
65 views

Beaglebone Black - Power sensors after boot

I am new to electronics and want to build a small thermometer/humidity sensor powered by a beaglebone black to get started on something practical. My issue is that the board doesn't start when the ...