simpletest fails on Feather nRF52840.

[kattni]

simpletest fails to run on Feather nRF52840. Throws the following exception:

        if crc8 != self._buf[5]:
            raise RuntimeError("CRC failure on reading word")

Same hardware worked successfully on Feather M4, so hardware is verified as functioning.

[ladyada]

@caternuson wanna try it again and slow down the clock, see if that helps?

[caternuson]

@ladyada for Feather (this issue) or on RPI (other issue #4)?

[ladyada]

feather - pi is resolved

[caternuson]

gotcha. yah, i'll set this up and check.

[caternuson]

Tried all the way down to 10kHz with CP 5.3.1. No change.

400kHz (default for CP 5.3.1)

Adafruit CircuitPython 5.3.1 on 2020-07-13; Adafruit Feather Bluefruit Sense with nRF52840
>>> import board
>>> from adafruit_lc709203f import LC709023F
>>> sensor = LC709023F(board.I2C()) 
>>> sensor.cell_voltage
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "adafruit_lc709203f.py", line 112, in cell_voltage
  File "adafruit_lc709203f.py", line 171, in _read_word
RuntimeError: CRC failure on reading word
>>>

100kHz

Adafruit CircuitPython 5.3.1 on 2020-07-13; Adafruit Feather Bluefruit Sense with nRF52840
>>> import board
>>> import busio
>>> from adafruit_lc709203f import LC709023F
>>> i2c = busio.I2C(board.SCL, board.SDA, frequency=100000)
>>> sensor = LC709023F(i2c)
>>> sensor.cell_voltage
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "adafruit_lc709203f.py", line 112, in cell_voltage
  File "adafruit_lc709203f.py", line 171, in _read_word
RuntimeError: CRC failure on reading word
>>> 

10kHz

Adafruit CircuitPython 5.3.1 on 2020-07-13; Adafruit Feather Bluefruit Sense with nRF52840
>>> import board
>>> import busio
>>> from adafruit_lc709203f import LC709023F
>>> i2c = busio.I2C(board.SCL, board.SDA, frequency=10000)
>>> sensor = LC709023F(i2c)
>>> sensor.cell_voltage
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "adafruit_lc709203f.py", line 112, in cell_voltage
  File "adafruit_lc709203f.py", line 171, in _read_word
RuntimeError: CRC failure on reading word
>>> 

[ladyada]

ok thankx - what an odd chip!

[caternuson]

want me to scope this or test further?

[ladyada]

nah

[anecdata]

Adafruit Feather M4 Express with samd51j19
6.1.0-beta.2 on 2020-12-03
adafruit-circuitpython-bundle-6.x-mpy-20210106

I'm getting this with simpletest.py, can get around it by just the right re-seating of the JST 2 PH connectors:

LC709023F simple test
Make sure LiPoly battery is plugged into the board!
Traceback (most recent call last):
  File "code.py", line 8, in <module>
  File "adafruit_lc709203f.py", line 102, in __init__
  File "adafruit_lc709203f.py", line 135, in power_mode
  File "adafruit_lc709203f.py", line 195, in _write_word
  File "adafruit_lc709203f.py", line 195, in _write_word
OSError: [Errno 5] Input/output error

But then:

  File "code.py", line 1798, in <module>
  File "adafruit_lc709203f.py", line 124, in ic_version
  File "adafruit_lc709203f.py", line 184, in _read_word
RuntimeError: CRC failure on reading word

I'll try slowing the I2C clock
...same with i2c = busio.I2C(board.SCL, board.SDA, frequency=10000)

...same CRC exception with a second LC7090203F board at 10,000Hz

[jameseleach]

I'm seeing this issue with a CLUE. It doesn't happen every time I query cell_voltage or cell_percent but I do not see a pattern as to when it happens. It happens at both the default clock speed and at 10,000Hz.

Adafruit CircuitPython 6.1.0 on 2021-01-21; Adafruit CLUE nRF52840 Express with nRF52840
>>> import board
>>> import busio
>>> from adafruit_lc709203f import LC709203F
>>> i2c = busio.I2C(board.SCL, board.SDA, frequency=100000)
>>> sensor = LC709203F(i2c)
>>> sensor.cell_voltage
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "adafruit_lc709203f.py", line 114, in cell_voltage
  File "adafruit_lc709203f.py", line 184, in _read_word
RuntimeError: CRC failure on reading word
>>> sensor.cell_voltage
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "adafruit_lc709203f.py", line 114, in cell_voltage
  File "adafruit_lc709203f.py", line 184, in _read_word
RuntimeError: CRC failure on reading word
>>> sensor.cell_voltage
4.163
>>> sensor.cell_voltage
4.163
>>> sensor.cell_percent
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "adafruit_lc709203f.py", line 119, in cell_percent
  File "adafruit_lc709203f.py", line 184, in _read_word
RuntimeError: CRC failure on reading word
>>> sensor.cell_percent
98.4
>>> sensor.cell_percent
98.4
>>> 

[TG-Techie]

I tried altering the simple_test.py to remove the sensor.cell_voltage read and the sensor.cell_percent reads start working, sometimes.

While trying to find the cause, I cleared the buffer before every read and write. Whenever the communication failed the buffer wasn't written and stayed cleared. Seems like the chip just isn't responding. I think the error might come from clock stretching, but that is merely speculation.

The datasheet says: (page 7)

* When you do not read CRC−8, LSI data is not reliable. CRC−8−ATM ex: (5 bytes) 0x16, 0x09, 0x17, 0xC2,
 0x0E → 0x86

Are they saying that the chip will send an invalid crc when it can't respond? Or just warning us to check the crc?

I'm not quite sure where to go from here but I thought these findings might be useful.

[jerryneedell]

here is a simple comparison from an nRF52840 (CLUE) and a metro_esp32s2 runnin gthe lc709203f_simpletest with the same version of cp and same library -- clearly something is amiss on the nrf52840....

same LC709203F and battery (500mAh) -- just moved from one board to the other

nrf52840 CLUE

Adafruit CircuitPython 6.2.0-beta.2-102-g2262af0b5 on 2021-02-22; Adafruit CLUE nRF52840 Express with nRF52840
>>> import lc709203f_simpletest
LC709203F simple test
Make sure LiPoly battery is plugged into the board!
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "lc709203f_simpletest.py", line 14, in <module>
  File "adafruit_lc709203f.py", line 124, in ic_version
  File "adafruit_lc709203f.py", line 184, in _read_word
RuntimeError: CRC failure on reading word
>>> 

metro_esp32s2

Adafruit CircuitPython 6.2.0-beta.2-102-g2262af0b5 on 2021-02-22; Adafruit Metro ESP32S2 with ESP32S2
>>> import lc709203f_simpletest
LC709203F simple test
Make sure LiPoly battery is plugged into the board!
IC version: 0x2717
Battery: 4.196 Volts / 100.0 %
Battery: 4.196 Volts / 100.0 %
Battery: 4.193 Volts / 100.0 %
Battery: 4.193 Volts / 100.0 %

also ran on a feather_bluefruit_sense

Press any key to enter the REPL. Use CTRL-D to reload.

Adafruit CircuitPython 6.2.0-beta.2-102-g2262af0b5 on 2021-02-22; Adafruit Feather Bluefruit Sense with nRF52840
>>> import lc709203f_simpletest
LC709203F simple test
Make sure LiPoly battery is plugged into the board!
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "lc709203f_simpletest.py", line 14, in <module>
  File "adafruit_lc709203f.py", line 124, in ic_version
  File "adafruit_lc709203f.py", line 184, in _read_word
RuntimeError: CRC failure on reading word
>>> 

nRF52840 seems to be consistent
this will be easier to connect the Logic analyzer to than the CLUE

[jerryneedell]

arrgh !! I hooked up my logic analyzer to compare the behavior of the nrf52840 and the esp32s2.
on the first captures on the nrf52840 I saw the same CRC failure but after reconnecting the metro esp32s2 to get a "clean" capture and switching back to the nrf52840, I am unable to get the nrf52840 to fail....with or without the logic analyzer connected

Adafruit CircuitPython 6.2.0-beta.2-102-g2262af0b5 on 2021-02-22; Adafruit Feather Bluefruit Sense with nRF52840
>>> import lc709203f_simpletest
LC709203F simple test
Make sure LiPoly battery is plugged into the board!
IC version: 0x2717
Battery: 4.207 Volts / 100.0 %
Battery: 4.207 Volts / 100.0 %
Battery: 4.207 Volts / 100.0 %

On the Clue, it is still failing. very odd

One difference is the connections - Using QWIIC on the CLUE - jumpers on the nrf52840 sense

It's getting late -- I will retry tomorrow.... with the logic analyzer on the Clue