Control GPIO, I2C and SPI
This package provide methods for controlling GPIO pins, I2C and SPI buses. This is written for A20-OLinuXino-LIME2, but it can be used with other boards. If you do this we cannot guarantee proper operation of the module. Before using this package we recommend reading the article at olimex wiki:
When using GPIO make sure that the desired gpio is not used by another periphery.
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 pyA20Lime2.gpio import port >>> dir(port)
By connector name and pin number: gpio2p12, gpio3p8, etc. These can be imported from connector module:>>> from pyA20Lime2.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
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
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
#!/usr/bin/env python from pyA20Lime2.gpio import gpio from pyA20Lime2.gpio import port from pyA20Lime2.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)
#!/usr/bin/env python from pyA20Lime2 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
#!/usr/bin/env python from pyA20Lime2 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!
- pyAA20Lime2 0.2.1 (30 JUN 2015)
- Fixed issue with SPI xfer function
- pyA20Lime2 0.2.0 (3 SEP 2014)
- Initial release