pi-fast-gpio

pi-fast-gpio

Super fast GPIO access on the Raspberry Pi using the pigpio daemon (for pwm, servo control, etc)

The pigpio library uses direct memory access (DMA) to allow you to sample the GPIOs up to 1,000,000 times per second. It also makes it fast enough to give you PWM and servo control on all GPIOs simultaneously. The servo waveforms are accurate to a few microseconds.

This code is based off of the python library included with the pigpio download.

Installation

For now you'll just have to clone this repo

Usage

Start the pigpio daemon:

$ sudo pigpiod

In your program:

1. require(...) the pi-fast-gpio library
2. Create a new instance of the PiFastGpio class
3. Call connect(...) to connect to the pigpiod daemon
4. When connected, do what you please with the GPIOs on your Raspberry Pi
5. Call close() when you're done and about to exit your program.

Examples

There are two examples included, one that drives two servos, and one that uses PWM to change the brightness of two LEDs

Before running any of the examples, make sure the pigpio daemon is running:

$ sudo pigpiod

Servos example

Watch the servos example in action here: http://youtu.be/AnlUtAq5oAM

Before running the example, please connect two servos to your Raspberry Pi. One on GPIO18 and one on GPIO23.

Go to the examples/ directory and run the code:

$ node js_servo.js

Watch the servos turn!

LED PWM example

Watch the LED PWM example in action here: http://youtu.be/OW6yF4NuwLE

Before running the example, please connect to LEDs to your Raspberry Pi with suitable resistors. Connect one LED to GPIO24 and one to GPIO25.

Go to the examples/ directory and run the code:

$ node js_pwm.js

Watch the LEDs light up with different brightness!

Pin Layout tables

(Tables copied from r-pi-gpio's readme file)

Raspberry Pi GPIO Pin Layout (Revision 1)

Assignment	Pin	Pin	Assignment
3.3V	1	2	5V
GPIO 0 (I2C0 SDA)	3	4	DNC
GPIO 1 (I2C0 SCL)	5	6	GROUND
GPIO 4	7	8	GPIO 14 (UART TXD)
DNC	9	10	GPIO 15 (UART RXD)
GPIO 17	11	12	GPIO 18
GPIO 21	13	14	DNC
GPIO 22	15	16	GPIO 23
DNC	17	18	GPIO 24
GPIO 10 (SP10 MOSI)	19	20	DNC
GPIO 9 (SP10 MISO)	21	22	GPIO 25
GPIO 11 (SP10 SCLK)	23	24	GPIO 8 (SP10 CE0 N)
DNC	25	26	GPIO 7 (SP10 CE1 N)

Raspberry Pi GPIO Pin Layout (Revision 2)

Assignment	Pin	Pin	Assignment
3.3V	1	2	5V
GPIO 2 (I2C1 SDA)	3	4	5V
GPIO 3 (I2C1 SCL)	5	6	GROUND
GPIO 4	7	8	GPIO 14 (UART TXD)
GROUND	9	10	GPIO 15 (UART RXD)
GPIO 17	11	12	GPIO 18
GPIO 27	13	14	GROUND
GPIO 22	15	16	GPIO 23
3.3V	17	18	GPIO 24
GPIO 10 (SP10 MOSI)	19	20	GROUND
GPIO 9 (SP10 MISO)	21	22	GPIO 25
GPIO 11 (SP10 SCLK)	23	24	GPIO 8 (SP10 CE0 N)
GROUND	25	26	GPIO 7 (SP10 CE1 N)