pyA20 0.2.12

Description:

pyA20 0.2.12

Description
The package provide methods for controlling GPIO pins, I2C and SPI
buses. It’s written for
A20-OLinuXino-MICRO,
but it can be used with other boards. In this case proper operation is
not guaranteed. You can check
wiki for more
information.
Notes:


When using GPIO make sure that the desired gpio is not used by another periphery.
Using this library requires root access.




GPIO methods
The following methods are available:

init() - Make initialization of the module. 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:

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:

>>> 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
The example consist of: * Initialize gpio module * Initialize one gpio
as output and another one as input * Polling input state and write
corresponding output value
#!/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
In this example: * I2C module is imported * Bus number 2 is opened *
Some data is written, then verified
#!/usr/bin/env python

from pyA20.i2c 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
In ths example: * SPI module is imported * Bus 2 with chip-select 0 is
opened * Some data is transfered to slave device
#!/usr/bin/env python

from pyA20.spi 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



Changelog

pyA20 0.2.12 (8 DEC 2017)


Fixed extensions import
Update examples



pyA20 0.2.11 (21 NOV 2017)


Fixed mapping on portG
Updated README
Removed processor checking to allow build scripts
Update license



pyA20 0.2.0 (02 SEP 2014)


Updated to enable SPI and I2C control
GPIO constant in separate modules
Added example files
Added support for Python3