Questions tagged [wiringpi]

WiringPi is a C language library for accessing GPIO pins.

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20
votes
3answers
64k views

Control Hardware PWM frequency

I'm using the hardware PWM output with wiringpi. It provides the function pwmSetClock that should make it possible to change the frequency. (https://projects.drogon.net/raspberry-pi/wiringpi/functions/...
1
vote
1answer
1k views

16 channel relay module does not respond to write 0/1 (GPIO.HIGH/LOW) commands

I have received a 16 channel relay module and I'm trying to drive it through my Raspberry Pi. I have connected a 12V power supply to the DC+/- of the board as well as the 2x +5V and 2x GND on the ...
6
votes
3answers
13k views

SPI: Raspberry PI master and Arduino slave

I'm trying to have a Raspberry PI act as a SPI master and send data to an Arduino Nano (one of the cheap clones). I partly succeeded, but I don't get a continuous communication, and some bytes get ...
0
votes
1answer
837 views

HC-SR04 ultrasonic sensor reading becomes highly unusable when PWM is active

Good day I am trying to sample distance using a sonar/ultrasonic sensor for altitude measurement. When the PWM is not active, the sensor gives accurate measurements in centimeters, however with the ...
5
votes
1answer
3k views

Using BCM GPIO pin numbers with wiringPi C library

I'm a GPIO newbie experimenting with getting my Raspberry Pi to blink an LED with C using the wiringPi library. The example code at http://wiringpi.com/examples/blink/ (blink.c) compiles perfectly and ...
4
votes
1answer
5k views

Read the value of an GPIO output pin

I've made a program using the wiringPi library that assigns GPIO pins to toggle at the press of associated number keys. I'd like my program to show the current status of the pins, even if they are ...
3
votes
3answers
5k views

Can we determine the mode of a GPIO pin?

As I understand it, the mode of a GPIO pin can be INPUT or OUTPUT (and I think there may be other modes such as PWM and I2C). I believe that the mode of a pin is a global and that if two applications ...
1
vote
2answers
3k views

wiringPi cleanup command

I have some experience with the python GPIO library and am working on porting some of my code to C for better performance. Normally, at the end of programs, or when I break out of them with Ctrl-C, I ...
0
votes
1answer
846 views

How to address gpio pins

I'm kind of new to raspberry pi, and I saw a tutorial about making a LED blink. The LED was connected to pin 17, but the tutorial said pin 11. I connected the LED to pin 17, and in the terminal I ...
0
votes
1answer
552 views

Monitor data sent to 74HC595

I'm new to Python and Raspberry Pi, so please bear with me. I would like to intercept the bytes of data being sent to a 74HC595 switch register. GPIO pin 23 on my RPi is connected to the data pin of ...