265 lines
7.6 KiB
Python
265 lines
7.6 KiB
Python
# The MIT License (MIT)
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#
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# Copyright (c) 2018 Shawn Hymel for Adafruit Industries
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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"""
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`adafruit_boardtest.boardtest_spi`
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====================================================
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Performs random writes and reads to SPI EEPROM.
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Run this script as its own main.py to individually run the test, or compile
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with mpy-cross and call from separate test script.
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* Author(s): Shawn Hymel for Adafruit Industries
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Implementation Notes
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--------------------
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**Hardware:**
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* `Microchip 25AA040A SPI EEPROM <https://www.digikey.com/product-detail/en/\
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microchip-technology/25AA040A-I-P/25AA040A-I-P-ND/1212469>`_
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**Software and Dependencies:**
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* Adafruit CircuitPython firmware for the supported boards:
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https://github.com/adafruit/circuitpython/releases
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* Adafruit's Bus Device library:
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https://github.com/adafruit/Adafruit_CircuitPython_BusDevice
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"""
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import random
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import time
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import board
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import digitalio
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import busio
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__version__ = "0.0.0-auto.0"
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__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_BoardTest.git"
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# Constants
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MOSI_PIN_NAME = "MOSI"
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MISO_PIN_NAME = "MISO"
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SCK_PIN_NAME = "SCK"
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CS_PIN_NAME = "D2"
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BAUD_RATE = 100000 # Bits per second
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NUM_SPI_TESTS = 10 # Number of times to write and read EEPROM values
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# Microchip 25AA040A EEPROM SPI commands and bits
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EEPROM_SPI_WRSR = 0x01
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EEPROM_SPI_WRITE = 0x02
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EEPROM_SPI_READ = 0x03
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EEPROM_SPI_WRDI = 0x04
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EEPROM_SPI_RDSR = 0x05
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EEPROM_SPI_WREN = 0x06
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EEPROM_SPI_WIP_BIT = 0
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EEPROM_SPI_MAX_ADDR = 255 # Self-imposed max memory address
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EEPROM_I2C_MAX_ADDR = 255 # Self-imposed max memory address
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# Test result strings
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PASS = "PASS"
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FAIL = "FAIL"
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NA = "N/A"
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# Wait for WIP bit to go low
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def _eeprom_spi_wait(spi, csel, timeout=1.0):
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# Continually read from STATUS register
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timestamp = time.monotonic()
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while time.monotonic() < timestamp + timeout:
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# Perfrom RDSR operation
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csel.value = False
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result = bytearray(1)
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spi.write(bytearray([EEPROM_SPI_RDSR]))
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spi.readinto(result)
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csel.value = True
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# Mask out and compare WIP bit
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if (result[0] & (1 << EEPROM_SPI_WIP_BIT)) == 0:
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return True
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return False
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# Write to address. Returns status (True for successful write, False otherwise)
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def _eeprom_spi_write_byte(spi, csel, address, data, timeout=1.0):
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# Make sure address is only one byte:
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if address > 255:
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return False
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# Make sure data is only one byte:
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if data > 255:
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return False
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# Wait for WIP to be low
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if not _eeprom_spi_wait(spi, csel, timeout):
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return False
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# Enable writing
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csel.value = False
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spi.write(bytearray([EEPROM_SPI_WREN]))
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csel.value = True
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# Write to address
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csel.value = False
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spi.write(bytearray([EEPROM_SPI_WRITE, address, data]))
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csel.value = True
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return True
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# Read from address. Returns tuple [status, result]
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def _eeprom_spi_read_byte(spi, csel, address, timeout=1.0):
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# Make sure address is only one byte:
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if address > 255:
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return False, bytearray()
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# Wait for WIP to be low
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if not _eeprom_spi_wait(spi, csel, timeout):
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return False, bytearray()
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# Read byte from address
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csel.value = False
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result = bytearray(1)
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spi.write(bytearray([EEPROM_SPI_READ, address]))
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spi.readinto(result)
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csel.value = True
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return True, result
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def run_test(
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pins,
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mosi_pin=MOSI_PIN_NAME,
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miso_pin=MISO_PIN_NAME,
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sck_pin=SCK_PIN_NAME,
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cs_pin=CS_PIN_NAME,
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):
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"""
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Performs random writes and reads to file on attached SD card.
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:param list[str] pins: list of pins to run the test on
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:param str mosi_pin: pin name of SPI MOSI
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:param str miso_pin: pin name of SPI MISO
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:param str sck_pin: pin name of SPI SCK
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:param str cs_pin: pin name of SPI CS
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:return: tuple(str, list[str]): test result followed by list of pins tested
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"""
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# Write values to SPI EEPROM and verify the values match
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if list(set(pins).intersection(set([mosi_pin, miso_pin, sck_pin]))):
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# Tell user to connect EEPROM chip
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print("Connect a Microchip 25AA040A EEPROM SPI chip.")
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print("Connect " + cs_pin + " to the CS pin on the 25AA040.")
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print("Press enter to continue.")
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input()
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# Configure CS pin
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csel = digitalio.DigitalInOut(getattr(board, cs_pin))
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csel.direction = digitalio.Direction.OUTPUT
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csel.value = True
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# Set up SPI
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spi = busio.SPI(
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getattr(board, sck_pin),
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MOSI=getattr(board, mosi_pin),
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MISO=getattr(board, miso_pin),
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)
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# Wait for SPI lock
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while not spi.try_lock():
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pass
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spi.configure(baudrate=BAUD_RATE, phase=0, polarity=0)
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# Pick a random address, write to it, read from it, and see if they match
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pass_test = True
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for _ in range(NUM_SPI_TESTS):
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# Randomly pick an address and a data value (one byte)
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mem_addr = random.randint(0, EEPROM_SPI_MAX_ADDR)
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mem_data = random.randint(0, 255)
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print("Address:\t" + hex(mem_addr))
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print("Writing:\t" + hex(mem_data))
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# Try writing this random value to the random address
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result = _eeprom_spi_write_byte(spi, csel, mem_addr, mem_data)
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if not result:
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print("FAIL: SPI could not communicate")
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pass_test = False
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break
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# Try reading the written value back from EEPRom
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result = _eeprom_spi_read_byte(spi, csel, mem_addr)
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print("Read:\t\t" + hex(result[1][0]))
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print()
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if not result[0]:
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print("FAIL: SPI could not communicate")
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pass_test = False
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break
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# Compare the read value to the original value
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if result[1][0] != mem_data:
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print("FAIL: Data does not match")
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pass_test = False
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break
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# Release SPI pins
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spi.deinit()
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# Return results
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if pass_test:
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return PASS, [mosi_pin, miso_pin, sck_pin]
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return FAIL, [mosi_pin, miso_pin, sck_pin]
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# Else (no pins found)
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print("No SPI pins found")
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return NA, []
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def _main():
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# List out all the pins available to us
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pins = list(dir(board))
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print()
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print("All pins found:", end=" ")
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# Print pins
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for pin in pins:
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print(pin, end=" ")
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print("\n")
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# Run test
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result = run_test(pins)
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print()
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print(result[0])
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print("Pins tested: " + str(result[1]))
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# Execute only if run as main.py or code.py
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if __name__ == "__main__":
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_main()
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