218 lines
6.4 KiB
Python
218 lines
6.4 KiB
Python
# The MIT License (MIT)
|
|
#
|
|
# Copyright (c) 2018 Shawn Hymel for Adafruit Industries
|
|
#
|
|
# Permission is hereby granted, free of charge, to any person obtaining a copy
|
|
# of this software and associated documentation files (the "Software"), to deal
|
|
# in the Software without restriction, including without limitation the rights
|
|
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
|
|
# copies of the Software, and to permit persons to whom the Software is
|
|
# furnished to do so, subject to the following conditions:
|
|
#
|
|
# The above copyright notice and this permission notice shall be included in
|
|
# all copies or substantial portions of the Software.
|
|
#
|
|
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
|
|
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
|
|
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
|
|
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
|
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
|
|
# THE SOFTWARE.
|
|
"""
|
|
`adafruit_boardtest.boardtest_i2c`
|
|
====================================================
|
|
Performs random writes and reads to I2C EEPROM.
|
|
|
|
Run this script as its own main.py to individually run the test, or compile
|
|
with mpy-cross and call from separate test script.
|
|
|
|
* Author(s): Shawn Hymel for Adafruit Industries
|
|
|
|
Implementation Notes
|
|
--------------------
|
|
|
|
**Hardware:**
|
|
|
|
* `Microchip AT24HC04B I2C EEPROM <https://www.digikey.com/product-detail/en/\
|
|
microchip-technology/AT24HC04B-PU/AT24HC04B-PU-ND/1886137>`_
|
|
|
|
**Software and Dependencies:**
|
|
|
|
* Adafruit CircuitPython firmware for the supported boards:
|
|
https://github.com/adafruit/circuitpython/releases
|
|
|
|
"""
|
|
|
|
import random
|
|
import time
|
|
|
|
import board
|
|
import busio
|
|
|
|
__version__ = "0.0.0-auto.0"
|
|
__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_BoardTest.git"
|
|
|
|
# Constants
|
|
SDA_PIN_NAME = "SDA"
|
|
SCL_PIN_NAME = "SCL"
|
|
NUM_I2C_TESTS = 10 # Number of times to write and read EEPROM values
|
|
EEPROM_I2C_MAX_ADDR = 255 # Self-imposed max memory address
|
|
|
|
# Microchip AT24HC04B EEPROM I2C address
|
|
EEPROM_I2C_ADDR = 0x50
|
|
|
|
# Test result strings
|
|
PASS = "PASS"
|
|
FAIL = "FAIL"
|
|
NA = "N/A"
|
|
|
|
# Open comms to I2C EEPROM by trying a write to memory address
|
|
def _eeprom_i2c_wait(i2c, i2c_addr, mem_addr, timeout=1.0):
|
|
|
|
# Try to access the I2C EEPROM (it becomes unresonsive during a write)
|
|
timestamp = time.monotonic()
|
|
while time.monotonic() < timestamp + timeout:
|
|
try:
|
|
i2c.writeto(i2c_addr, bytearray([mem_addr]), end=1)
|
|
return True
|
|
except OSError:
|
|
pass
|
|
|
|
return False
|
|
|
|
|
|
# Write to address. Returns status (True for successful write, False otherwise)
|
|
def _eeprom_i2c_write_byte(i2c, i2c_addr, mem_addr, mem_data):
|
|
|
|
# Make sure address is only one byte:
|
|
if mem_addr > 255:
|
|
return False
|
|
|
|
# Make sure data is only one byte:
|
|
if mem_data > 255:
|
|
return False
|
|
|
|
# Write data to memory at given address
|
|
try:
|
|
i2c.writeto(i2c_addr, bytearray([mem_addr, mem_data]))
|
|
except OSError:
|
|
return False
|
|
|
|
return True
|
|
|
|
|
|
# Read from address. Returns tuple [status, result]
|
|
def _eeprom_i2c_read_byte(i2c, i2c_addr, mem_addr, timeout=1.0):
|
|
|
|
# Make sure address is only one byte:
|
|
if mem_addr > 255:
|
|
return False, bytearray()
|
|
|
|
# Try writing to address (EEPROM is unresponsive while writing)
|
|
if not _eeprom_i2c_wait(i2c, i2c_addr, mem_addr, timeout):
|
|
return False, bytearray()
|
|
|
|
# Finish the read
|
|
buf = bytearray(1)
|
|
i2c.writeto_then_readfrom(i2c_addr, bytearray([mem_addr]), buf)
|
|
|
|
return True, buf
|
|
|
|
|
|
def run_test(pins, sda_pin=SDA_PIN_NAME, scl_pin=SCL_PIN_NAME):
|
|
|
|
"""
|
|
Performs random writes and reads to I2C EEPROM.
|
|
|
|
:param list[str] pins: list of pins to run the test on
|
|
:param str sda_pin: pin name of I2C SDA
|
|
:param str scl_pin: pin name of I2C SCL
|
|
:return: tuple(str, list[str]): test result followed by list of pins tested
|
|
"""
|
|
|
|
# Write values to I2C EEPROM and verify the values match
|
|
if list(set(pins).intersection(set([sda_pin, scl_pin]))):
|
|
|
|
# Tell user to connect EEPROM chip
|
|
print(
|
|
"Connect a Microchip AT24HC04B EEPROM I2C chip. "
|
|
+ "Press enter to continue."
|
|
)
|
|
input()
|
|
|
|
# Set up I2C
|
|
i2c = busio.I2C(getattr(board, scl_pin), getattr(board, sda_pin))
|
|
|
|
# Wait for I2C lock
|
|
while not i2c.try_lock():
|
|
pass
|
|
|
|
# Pick a random address, write to it, read from it, and see if they match
|
|
pass_test = True
|
|
for _ in range(NUM_I2C_TESTS):
|
|
|
|
# Randomly pick an address and a data value (one byte)
|
|
mem_addr = random.randint(0, EEPROM_I2C_MAX_ADDR)
|
|
mem_data = random.randint(0, 255)
|
|
print("Address:\t" + hex(mem_addr))
|
|
print("Writing:\t" + hex(mem_data))
|
|
|
|
# Try writing this random value to the random address
|
|
result = _eeprom_i2c_write_byte(i2c, EEPROM_I2C_ADDR, mem_addr, mem_data)
|
|
if not result:
|
|
print("FAIL: I2C could not communicate")
|
|
pass_test = False
|
|
break
|
|
|
|
# Try reading the written value back from EEPROM
|
|
result = _eeprom_i2c_read_byte(i2c, EEPROM_I2C_ADDR, mem_addr)
|
|
print("Read:\t\t" + hex(result[1][0]))
|
|
print()
|
|
if not result[0]:
|
|
print("FAIL: I2C could not communicate")
|
|
pass_test = False
|
|
break
|
|
|
|
# Compare the read value to the original value
|
|
if result[1][0] != mem_data:
|
|
print("FAIL: Data does not match")
|
|
pass_test = False
|
|
break
|
|
|
|
# Release I2C pins
|
|
i2c.deinit()
|
|
|
|
# Store results
|
|
if pass_test:
|
|
return PASS, [sda_pin, scl_pin]
|
|
|
|
return FAIL, [sda_pin, scl_pin]
|
|
|
|
# Else (no pins found)
|
|
print("No I2C pins found")
|
|
return NA, []
|
|
|
|
|
|
def _main():
|
|
|
|
# List out all the pins available to us
|
|
pins = list(dir(board))
|
|
print()
|
|
print("All pins found:", end=" ")
|
|
|
|
# Print pins
|
|
for pin in pins:
|
|
print(pin, end=" ")
|
|
print("\n")
|
|
|
|
# Run test
|
|
result = run_test(pins)
|
|
print()
|
|
print(result[0])
|
|
print("Pins tested: " + str(result[1]))
|
|
|
|
|
|
# Execute only if run as main.py or code.py
|
|
if __name__ == "__main__":
|
|
_main()
|