59 lines
1.2 KiB
Python
59 lines
1.2 KiB
Python
import board
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import busio
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import digitalio
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cs = digitalio.DigitalInOut(board.SS)
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cs.direction = digitalio.Direction.OUTPUT
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cs.value = True
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BME680_SPI_REGISTER = 0x73
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BME680_CHIPID_REGISTER = 0xD0
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BME680_CHIPID = 0x61
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SPI_HERZ = 0x500000
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spi = busio.SPI(board.SCK, MISO=board.MISO, MOSI=board.MOSI)
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def readByte(addr):
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value = -1
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while not spi.try_lock():
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pass
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try:
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spi.configure(baudrate=500000, phase=0, polarity=0)
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cs.value = False
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result = bytearray(1)
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result[0] = addr | 0x80
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spi.write(result)
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spi.readinto(result)
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value = result[0]
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return value
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finally:
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spi.unlock()
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cs.value = True
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def writeByte(addr, value):
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while not spi.try_lock():
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pass
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try:
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spi.configure(baudrate=500000, phase=0, polarity=0)
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cs.value = False
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result = bytearray(2)
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result[0] = addr & ~0x80
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result[1] = value
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spi.write(result)
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finally:
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spi.unlock()
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# put the device in the correct mode to read the ID
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reg = readByte(BME680_SPI_REGISTER)
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if (reg & 16) != 0:
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writeByte(BME680_SPI_REGISTER, reg & ~16)
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id = readByte(BME680_CHIPID_REGISTER)
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print(f"id is {id}, expected {BME680_CHIPID}")
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