本文整理汇总了Python中spidev.SpiDev.xfer方法的典型用法代码示例。如果您正苦于以下问题：Python SpiDev.xfer方法的具体用法？Python SpiDev.xfer怎么用？Python SpiDev.xfer使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类spidev.SpiDev的用法示例。
在下文中一共展示了SpiDev.xfer方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的Python代码示例。
示例1: Matrix
# 需要导入模块: from spidev import SpiDev [as 别名]
# 或者: from spidev.SpiDev import xfer [as 别名]
class Matrix(object):
'''
The class which models the operation of the Olimex 8x8 RGB LED matrix.
The numbering scheme used when defining the pins are with respect to
the BCM numbering scheme.
Wiring:
- VCC = driving voltage for the matrix. 5 volts.
- GND = ground connection from the matrix.
- DIN = data in for the matrix, GPIO pin 10 (SPI MOSI).
- CS = chip select, depending on SPI channel selection.
- CLK = serial clock, GPIO pin 11 (SPI SCK).
'''
def __init__(self, spidevice=0):
'''
Basic constructor for our driver class.
@param: spidevice - the SPI device to be used.
Acts as a chip-enable. The Raspberry PI B+ has two such device
output pins in-built.
Defaults to 0.
@return: None
'''
if spidevice != 1:
spidevice = 0
self.__spi = SpiDev()
self.__spi.mode = 0b01
self.__spi.open(0, spidevice)
self.__buffer = [0] * 24
def drawpixel(self, pixel):
'''
Draws a given Pixel object to the internal buffer.
The buffer is formed of 24 bytes.
Each byte represents a single color, the n'th bit being whether
that particular color is active in the n'th led of that row.
The colors are ordered in reverse. (BGR).
@param: pixel - a Pixel object.
@return: the Pixel encoded as a byte.
'''
# current row we're on:
row = 3 * pixel.y
# clear currently present color by unsetting the corresponding bit from
# the three color bytes:
self.__buffer[row] &= ~(1 << pixel.x) # clear red.
self.__buffer[row + 1] &= ~(1 << pixel.x) # clear green.
self.__buffer[row + 2] &= ~(1 << pixel.x) # clear blue.
# set red bit for this pixel, if necessary:
if pixel.color in [Color.red, Color.white, Color.brown, Color.purple]:
self.__buffer[row] |= 1 << pixel.x
# set green bit:
if pixel.color in [Color.green, Color.white, Color.turquoise, Color.brown]:
self.__buffer[row + 1] |= 1 << pixel.x
# set blue bit:
if pixel.color in [Color.blue, Color.white, Color.turquoise, Color.purple]:
self.__buffer[row + 2] |= 1 << pixel.x
def write(self):
'''
Serially writes the whole of the video buffer to the matrix.
'''
self.__spi.xfer(self.__buffer)
def clear(self):
'''
Clears both the internal buffer and the matrix.
'''
self.__buffer = [0] * 24
self.write()
def cleanup(self):
'''
Clears all registers and terminates the SPI connection.
'''
self.clear()
self.__spi.close()