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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32 views

How to read decade counter with minimum pins

I just obtained some of these counters for a project: They have five connections for each slice labelled C, 1, 2, 4, and 8. As you increment the digit, the pins for the appropriate binary encoding ...
9
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4answers
478 views

1.5V-rated MOSFET doesn't react to a gate input of 1.8V

I am not really an electronics specialist, but a software engineer (so excuses if I 'm asking stupid questions). I am trying to use a microcontroller GPIO output rated at 1.8V. When this pin becomes ...
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1answer
110 views

Using GPIO pins as software I2C pins and finding analog value of those pins

I am using AT32UC3C microcontroller which has 64 pins. I am using gpio pin PB01 as SCK and gpio pin PA04 as SDA and ticking then manually high and low. These pins are configured as GPIO_OPEN_DRAIN and ...
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2answers
144 views

SMD vs THR Transistor for Relay

Designing a Relay control from a MCU's GPIO, there are some requirements to take into account. Coil Voltage: 3V Coil Resistance: [36-45]Ohm Relay Voltage: 250Vac // 30Vcc GPIO Voltage: 3V3 Max GPIO ...
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0answers
33 views

Testing an A-D converter of an ARM microcontroller

all. I am playing around with a development board that is using an ARM microcontroller and was wondering what would be a short and simple way of testing the A-D converter of the microcontroller. I am ...
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3answers
68 views

Digital Input Clamp Circuit Protection

To be able to connect some peripheral to digital input, I'm designing the circuit protection to avoid any possible failure due to over/under-voltage issue. So, I will add a clamp protection circuit. ...
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1answer
93 views

Negative voltage on input pins

Hope that someone can help me: I found a schematics to program microcontroller from Raspberry PI (http://mujweb.cz/tlc/rpp/) and modified it a bit (will use direct 12V and 5V power supply). I'm ...
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2answers
21 views

Low leakage current methods of initializing pin inputs at power up

Suppose I have an IC that has a standard level triggered input pin. I need this pin's state to be setup immediately at power on at a time when my MCU's GPIOs may not have established levels. What are ...
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0answers
25 views

How to configure digital output in Renesas RH850/F1L Microcontroller?

I need to configure pin AP0_14 for digital output. To achieve this I need to write 0 to bit 14 of 16-bit Port Mode Register. The physical address of this register is: 0xFFC103C8 What should be ...
4
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2answers
144 views

Why do I need this relay?

Hopefully I don't get torn apart for such a noobie question (but how else do you learn right?). I got a Raspberry Pi to hopefully learn a bit about electronics (and because it was 35 dollars). I asked ...
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2answers
51 views

Rising DC Voltage

I only have 3.3 DC Voltage on the pin of PCB and I want to supply a chip 5V. What are the ways to manage this? PS: The voltage on the pin is always 3.3 V and max current on it can be 50 mA.
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1answer
28 views

Atmega 328 with DS1620 thermometer chip. Why is a pull-up resistor needed on the DQ line

I think understand the purpose of pull up resistors in general but in this particular case the DS1620 datasheet says that in the output mode it sources a current of 1ma (see footnote 5 on the last ...
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1answer
115 views

STM32F103 GPIO not working

I am programming for LPC microcontrollers (mostly LPC1769), for the past few months with success. I decided though to give STM32 series a try. I just received a no-name board using an STM32F103C8 MCU ...
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2answers
156 views

PIC18 GPIO switch from input to output(dual mode)

I have always wondered if it is possible to switch the port direction of the PIC GPIO during the course of the program execution. So, for instance I start with a particular port set as an ...
2
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1answer
169 views

Using NPN BJT with a P Channel MOSFET to switch 3.3V to 24V

simulate this circuit – Schematic created using CircuitLab I have some 3.3V I/O on a PC Board. When an output is switched on, I need to switch the 3.3V output voltage with a +24VDC and ...
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1answer
50 views

Safely connecting signal GPIOs

I'm using an STM32L053 MCU to interface to a poorly-documented PCB module (DRA818V). There are a couple of GPIO driven signals as well as a UART involved, and I want to make sure I'm doing things ...
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1answer
62 views

How to use 2 power supplies in my scheme?

I am building a device to send a signal from Raspberry Pi GPIO to a vibration motor. Here is how it should work: the RPI outputs 0v or 3.3v, and when it outputs 3.3v, the vibration motor should ...
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3answers
94 views

Why smartphone IR system uses an IC instead of GPIO?

I have an android based embedded system, and I would like to command ir controlled devices, such as tv, air conditioner, sound system...etc. I need both rx and tx. When I see examples on internet, ...
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2answers
93 views

Can a logic level converter be used as a replacement for a relay for detecting if a buzzer is currently active?

I have a small microcontroller (VoCore, runs Linux, has wifi and GPIOs) and i want to use it to hook into another system (basically a doorbell) to make the state of the doorbell-buzzer available over ...
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0answers
68 views

S_axilite port, how to deal with AXI GPIO

I have a block made in Vivado HLS that receives 3 parameters: 1-Map_in which is a matrix of values to be normalized. My objective is to connect it to DDR via AXI DMA 2-Map_out which is a matrix of ...
4
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2answers
70 views

Design Considerations for Raspberry Pi Expansion Boards

I am venturing into the space of designing expansion boards for Raspberry Pi's. I have done this for Arduino boards but RPi's are a different beast. From personal experience I have already had ...
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4answers
85 views

Use GPIO to disable voltage divider

I'm using a voltage divider to read the battery level of a wireless sensor platform using STM32L151. I'm shooting to use 20k for R1 and 10k for R2, to be under the 50k limit of the MCU's ADC ...
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1answer
89 views

tri-state / high-z / high impedance output with gpio input

The Li-ion charger I'm using (MCP73831/2) has a tri-state status output. The datasheet says that the STAT pin outputs High-Z when inactive or complete, and Low while charging is active. Whats the ...
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0answers
43 views

Reading analogue input using digital GPIO

I'm using soil hygrometer to measure soil moisture. Since I don't have adc I'm using This method. Please tell me how to connect resistor and capacitor along with amount of resistance and capacitance. ...
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1answer
115 views

What is drive strength a measurement of?

In microcontrollers and the like that have programmable drive strengths for GPIOs, said drive strengths are defined in mA. For example you might have a choice of 2mA, 4mA, 6mA, 8mA, etc. My ...
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2answers
78 views

GPIO Input fluctuating between high and low when no input is received

I posted this on the Raspberry Pi StackExchange but I feel as though it might be better suited for here, as the SE is pretty inactive anyway. I've got a fairly simple circuit that I've made where a ...
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1answer
67 views

DIY Photobooth: LED puck lights potentiometer suggestions

I'm building a Raspberry Pi powered photobooth, and want to add some lighting. I purchased this set of led puck lights, and would love to control their intensity from the Raspberry Pi, instead of the ...
3
votes
3answers
757 views

how to increase the voltage of a digital signal?

I'd like my Raspberry Pi GPIO port to communicate with a digital circuit that works at 2x the GPIO voltage. The communication will be at a relatively high frequency (up to 500kHz). The main question ...
0
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1answer
56 views

Transistor Switch to Pull to Ground (Broadcast GPIO)

I have a Sonifex Net-log audio recording device. It can be configured to begin recording on remote input. From the manual: The remote inputs and output can be driven by 5V logic. The inputs are ...
0
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1answer
114 views

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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1answer
104 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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63 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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1answer
91 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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1answer
62 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
276 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
31 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 ...
3
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2answers
660 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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0answers
179 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 ...
1
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1answer
74 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 ...
0
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2answers
134 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 ...
1
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1answer
89 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
212 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 ...
0
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2answers
213 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
129 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 ...
0
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1answer
118 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
90 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
63 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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0answers
62 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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0answers
158 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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0answers
24 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 ...