ShiftPi

ShiftPi is the easiest way to work with 74HC595 or TPIC6C595 shift registers on your Raspberry Pi in Arduino style :). If you are an Arduino fan ... you will love it :) This library is inspired from this article: Can you move over? The 74HC595 8 bit shift register

How to connect Pi with `74HC595`

How to connect Pi with `TPIC6C595`

Note how the LED's are reversed in this diagram, this is because the ouputs on the TPIC6C595 are current drains, that is to say they "pull" current through the LED, rather then "push" the current as the 74HC595 does

#Quick Example ... Arduino style :) So ... Let's have a look how can we create some magic :)

from shiftpi import HIGH, LOW, digitalWrite, delay

while True:
    digitalWrite(1, HIGH)
    delay(1000)
    digitalWrite(1, LOW)
    delay(1000)

Looks familiar? :)) The Blink example ?? Do you like it? :) Cool :))

How can I use the library?

So if you are not familiar with python you can use the library in 2 ways:

import shiftpi

# turns shift register's pin 1 to HIGH
shiftpi.digitalWrite(1, shiftpi.HIGH)
shiftpi.delay(1000)

# turns shift register's pin 1 to LOW
shiftpi.digitalWrite(1, shiftpi.LOW)
shiftpi.delay(1000)

# turns all shift register pins to HIGH
shiftpi.digitalWrite(shiftpi.ALL, shiftpi.LOW)
shiftpi.delay(1000)

or you can use the library methods as shown in the first example, with importing all methods from the shiftpi library. If I want to set all shift register's pins to HIGH I can do the following:

from shiftpi import HIGH, LOW, ALL, digitalWrite, delay

digitalWrite(ALL, HIGH)

That's it! :)

The API look and feel

In all examples below i will use the second way of importing methods. (from shiftpi import bla bla)

Constants

HIGH # this is mode of pin
LOW # this is mode of pin
ALL # you can use it as pin number.

pinsSetup(dict)

By the way by default SER, RCLK, SRCLK are set as follow:

SER = 25 (GPIO RPI) #pin 14 on the 75HC595
RCLK = 24 (GPIO RPI) #pin 12 on the 75HC595
SRCLK = 23 (GPIO RPI) #pin 11 on the 75HC595

But ... if you want to use other GPIOs ... you can define them with the following method:

pinsSetup({"ser": SER_PIN, "rclk": RCLK_PIN, "srclk": SRCLK_PIN}) # that's it!

shiftRegisters(num)

By default shiftpi works with 1 shift register, but if you use more than one shift register you can set the number of all shift registers you use, with this method:

shiftRegisters(3) # if you use 3 shift registers

startupMode(mode or dict, execute)

By default if you use the library for first time all your pins will be set to LOW, but if you want to use some other different configuration you can try with this method.

# this will set all your pins to `HIGH` but will not execute them.
startupMode(HIGH)

# if you want to set all your pins to `HIGH` and it will execute them automaticaly ... try this
startupMode(HIGH, True) # works just like digitalWrite(ALL, HIGH)

# if you want to set only few pins to some mode ... try this
startupMode({1: HIGH, 4: HIGH, 6: HIGH})

# and if you want to execute them ...
startupMode({1: HIGH, 4: HIGH, 6: HIGH}, True)

digitalWrite(pin, mode)

The digitalWrite method is inspired from the Arduino API and it works as you expect

If you want to turn 3rd pin of the shift register to HIGH

digitalWrite(3, HIGH)

or if you want to turn on all pins of the shift register to HIGH

digitalWrite(ALL, HIGH) # will turn on all pins to HIGH

delay(millis)

If you are an Arduino guy you just need to know that this method works just like the Arduino's delay

delay(30) # will sleep for 30 millis

#Requirements

Raspberry Pi
Python 2.6+ and Python development tools
RPi.GPIO (latest version recommended)

Installation

First install RPi.GPIO library and Python development tools:

# sudo apt-get update && sudo apt-get -y install python-rpi.gpio python-dev

Get shiftpi source and install it:

# git clone git://github.com/mignev/shiftpi.git
# sudo python shiftpi/setup.py install

After installation, you can remove the folder as it is no longer needed by running:

# sudo rm -rf shiftpi

Testing

TODO

Contributing

Fork the shiftpi repo on GitHub, make your super duper awesome changes :) and send me a Pull Request. :)

Contributors

Useful links

How Shift Registers work? (Video)

mignev/shiftpi