A CHIP IO library for C: IO+PWM
Arduino Style GPIO control for C.H.I.P and C.H.I.P Pro
Attach an LED to XIO-P2 with a resistor to run the blink example::
sudo apt-get install git build-essential -y
git clone https://github.com/Groguard/CHIP_IO.git
cd CHIP_IO/examples/
arm-linux-gnueabihf-gcc -pthread blink.c ../chip_io_c.c ../source/event_gpio.c ../source/common.c -o blink -static
sudo ./blink
GPIO Setup
#include "chip_io_c.h"
pinMode("CSID0", OUTPUT);
You can also refer to the pin number:
pinMode("U14_31", OUTPUT);
You can also refer to the bin based upon its alternate name:
pinMode("GPIO1", INPUT);
Debug can be enabled/disabled by the following command:
// Enable Debug
toggle_debug();
GPIO Output
Setup the pin for output, and write HIGH or LOW. Or you can use 1 or 0:
#include "chip_io_c.h"
pinMode("CSID0", OUTPUT);
digitalWrite("CSID0", HIGH);
GPIO Input
Inputs work similarly to outputs.:
#include "chip_io_c.h"
pinMode("CSID0", INPUT);
Other options when setting up pins:
// Specify pull up/pull down settings on a pin
pinMode("CSID0", INPUT_PULLUP);
pinMode("CSID0", INPUT_PULLDOWN);
Pull Up/Down values are only for pins that are provided by the R8, the XIO are not capable of this. The allowable values are: INPUT_PULLOFF, INPUT_PULLUP, and INPUT_PULLDOWN.
Polling inputs:
int state = digitalRead("CSID0");
if(state)
printf("HIGH\n");
else
printf("LOW\n");
GPIO Cleanup
To clean up the GPIO when done, do the following:
// Clean up a single pin (keeping everything else intact)
cleanup("XIO-P0");
// Clean up all
cleanup("ALL");
PWM
Hardware PWM requires a DTB Overlay loaded on the CHIP to allow the kernel to know there is a PWM device available to use. Works by defualt on CHIPPro
//startPwm(channel, duty, polarity);
#inlcude "chip_io_c_pwm.h"
startPwm("PWM0", 50, 0);
//duty values are valid 0 (off) to 100 (on)
setPwmDutyCycle("PWM0", 20.5);
setPwmFrequency("PWM0", 50);
// to Stop PWM
stopPwm("PWM0");
cleanupPwm("PWM0");