Movitz Aaron
50e4ba8a07
Source-only snapshot of the 1.2 release. Drivers/ (the vendored ST HAL and CMSIS) is excluded at 173 MB; fetch it from STMicroelectronics/STM32CubeH5 to build.
67 lines
2.2 KiB
Python
67 lines
2.2 KiB
Python
import spidev
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import RPi.GPIO as GPIO
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global spi
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PISPI_BUFFER_SIZE = 256 # Buffer size must match between Pi and STM32
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# Pin number for our CS pin repurposed as a ready pin
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ReadyPin = 8
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# Initialise the SPI communications
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# You must pass in the pigpio handle
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# Speed is optional, defaults to 1MHz
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def YEEPiInit(speed=1000000):
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# Global these so they can be used later
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global spi
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spi = spidev.SpiDev() # Create SPI object
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spi.open(0,0) # Open SPI bus 0 device 0
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spi.max_speed_hz = speed # Set speed to inputted speed
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spi.mode = 0 # Set SPI mode to 0
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spi.no_cs = True # Disable chip select
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GPIO.setmode(GPIO.BCM)
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GPIO.setup(ReadyPin, GPIO.IN, pull_up_down=GPIO.PUD_OFF)
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# Execute a transfer to YEEP, exchanging buffers
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# Takes a bytearray of values and returns a bytearray
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# with the received data
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#
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# Input data smaller than the buffer size will be padded to correct size
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# with null bytes. Input data larger will be truncated
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# Warnings will be printed in the cases of an array being truncated
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# or if received data is blank
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def YEEPiTransfer(TXBuf):
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# Check that the input data is a byte array, error if not
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if not isinstance(TXBuf, bytearray):
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raise TypeError("Data must be byte array")
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# Check if the array is larger, and delete extra entries
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if len(TXBuf) > PISPI_BUFFER_SIZE:
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print("Warning: Array larger than buffer size, truncating")
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del TXBuf[PISPI_BUFFER_SIZE:] # Delete entries beyond buffer size
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# Pad the array to the full size if required
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TXBuf = TXBuf.ljust(PISPI_BUFFER_SIZE, b'\0') #Pad to buffer size with null bytes
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# Wait until ready pin is asserted
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while not GPIO.input(ReadyPin):
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pass # Pass immediatly restarts the loop with no delay - we don't want to wait any longer than we have to
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# Execute the transfer
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RXBuf = spi.xfer(TXBuf)
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# If the received buffer is all 0, warn the user
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if sum(RXBuf) == 0:
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print("Warning: Empty message received")
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# Convert returned list to bytearray
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return bytearray(RXBuf)
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# This should be called when the program exits
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def YEEPiExit():
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GPIO.cleanup() |