This package provide methods for controlling GPIO pins, I2C and SPI buses.

based on pyA20 written for A20-OLinuXino-MICRO (https://pypi.python.org/pypi/pyA20)

When using GPIO make sure that the desired gpio is not used by another periphery.

GPIO METHODS

init()      -   Make initialization of the module. Always must be called first.
getcfg()    -   Read current configuration of gpio.
setcfg()    -   Write configuration to gpio.
input()     -   Return current value of gpio.
output()    -   Set output value.
pullup()    -   Set pull-up/pull-down.

The available constants are:

NAME        -   EQUALS TO
====            =========
HIGH        ->      1
LOW         ->      0
INPUT       ->      0
OUPTUT      ->      1
PULLUP      ->      1
PULLDOWN    ->      2

The gpio are named two ways:

By port name: PH0, PG2, PE10, etc.
These can be imported from port module:

>>> from pyA20.gpio import port
>>> dir(port)

By connector name and pin number: gpio2p12, gpio3p8, lcdp18, uext1p3 and etc.
These can be imported from connector module:

>>> from pyA20.gpio import connector
>>> dir(connector)

Generally these constants are just an offset in the memory from the base GPIO address, so they can be assigned to a number type variable.

>>> led = port.PH2
>>> print led
226

I2C METHODS

init()      -   Make initialization of the module
open()      -   Begin communication with slave device
read()      -   Read from slave device
write()     -   Write data to slave device
close()     -   End communication with slave device

SPI METHODS

open()      -   Open SPI bus with given configuration
read()      -   Read data from slave device without write
write()     -   Write data to slave device without read
xfer()      -   Do write and after that read
close()     -   Close SPI bus

Examples

GPIO::

#!/usr/bin/env python

from pyA20.gpio import gpio
from pyA20.gpio import port
from pyA20.gpio import connector

gpio.init() #Initialize module. Always called first

gpio.setcfg(port.PG9, gpio.OUTPUT)  #Configure LED1 as output
gpio.setcfg(port.PG9, 1)    #This is the same as above

gpio.setcfg(port.PE11, gpio.INPUT)   #Configure PE11 as input
gpio.setcfg(port.PE11, 0)   #Same as above

gpio.pullup(port.PE11, 0)   #Clear pullups
gpio.pullup(port.PE11, gpio.PULLDOWN)    #Enable pull-down
gpio.pullup(port.PE11, gpio.PULLUP)  #Enable pull-up

while True:
    if gpio.input(port.PE11) == 1:
        gpio.output(port.PG9, gpio.LOW)
        gpio.output(port.PG9, 0)
    else:
        gpio.output(port.PG9, gpio.HIGH)
        gpio.output(port.PG9, 1)

I2C::

#!/usr/bin/env python

from pyA20 import i2c

i2c.init("/dev/i2c-2")  #Initialize module to use /dev/i2c-2
i2c.open(0x55)  #The slave device address is 0x55

#If we want to write to some register
i2c.write([0xAA, 0x20]) #Write 0x20 to register 0xAA
i2c.write([0xAA, 0x10, 0x11, 0x12]) #Do continuous write with start address 0xAA

#If we want to do write and read
i2c.write([0xAA])   #Set address at 0xAA register
value = i2c.read(1) #Read 1 byte with start address 0xAA

i2c.close() #End communication with slave device

SPI::

#!/usr/bin/env python

from pyA20 import spi

spi.open("/dev/spidev2.0")
#Open SPI device with default settings
# mode : 0
# speed : 100000kHz
# delay : 0
# bits-per-word: 8

#Different ways to open device
spi.open("/dev/spidev2.0", mode=1)
spi.open("/dev/spidev2.0", mode=2, delay=0)
spi.open("/dev/spidev2.0", mode=3, delay=0, bits_per_word=8)
spi.open("/dev/spidev2.0", mode=0, delay=0, bits_per_word=8, speed=100000)

spi.write([0x01, 0x02]) #Write 2 bytes to slave device
spi.read(2) #Read 2 bytes from slave device
spi.xfer([0x01, 0x02], 2)   #Write 2 byte and then read 2 bytes.

spi.close() #Close SPI bus

It's important that you run your python script as root!