While accesing sensors on the RP2040 give results that are not as expected when not using the REPL

[jposada202020]

While accessing two sensors in this case:
BH1750
MMA8451

This is seeing mostly in the RP2040. Have tested with the SAMD51 and the nRF52840 without seeing this issue.

Error

>>> import test_two_sensors
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "test_two_sensors.py", line 12, in <module>
  File "/lib/adafruit_mma8451.py", line 120, in __init__
ValueError: No I2C device at address: 1d

test code

import time
import board
import adafruit_mma8451
import adafruit_tca9548a
import adafruit_bh1750

# import test_two_sensors

i2c = board.I2C()
tca = adafruit_tca9548a.TCA9548A(i2c)
sensor2 = adafruit_bh1750.BH1750(tca[4])
sensor = adafruit_mma8451.MMA8451(tca[1])


while True:
    x, y, z = sensor.acceleration
    print("Acceleration: x={0:0.3f}m/s^2 y={1:0.3f}m/s^2 z={2:0.3f}m/s^2".format(x, y, z))
    time.sleep(1)
    print("%.2f Lux" % sensor2.lux)
    time.sleep(1)

Other Information

• The test is done using a file and not in writing the instructions in the REPL.
• This behavior is seeing with other sensors as MPL3115A2. My tests are not conclusive if the BH1750 are in fault or is the RP2040, or the REPL.
• Sometimes, while testing the first test will be ok, but then it will not work again, not even unplugging the RP2040 from the USB connection

[jerryneedell]

Just to add some more information -- I have a BH1750 and a BME680 attached via a tca9548a to a feather_rp2040
I can access either sensor OK individually but often (not always) get failures when I try to access both.
Here are some tests -- I did a soft boot (control-D) between each test
scantest

Adafruit CircuitPython 7.0.0-alpha.2-673-gd79d68705 on 2021-05-25; Adafruit Feather RP2040 with rp2040
>>> import scantest2
Scan of Main I2C Channel:['0x70']
Channel 0:['0x70']
Channel 1:['0x23', '0x70']
Channel 2:['0x70']
Channel 3:['0x70']
Channel 4:['0x70', '0x77']
Channel 5:['0x70']
Channel 6:['0x70']
Channel 7:['0x70']
>>> 

just the bme680

Adafruit CircuitPython 7.0.0-alpha.2-673-gd79d68705 on 2021-05-25; Adafruit Feather RP2040 with rp2040
>>> import tca_bme680
26.16 temperature
26.18 temperature

just the bh1750

Adafruit CircuitPython 7.0.0-alpha.2-673-gd79d68705 on 2021-05-25; Adafruit Feather RP2040 with rp2040
>>> import tca_bh1750
91.67 Lux
91.25 Lux

First try accessing both works OK --

Adafruit CircuitPython 7.0.0-alpha.2-673-gd79d68705 on 2021-05-25; Adafruit Feather RP2040 with rp2040
>>> 
>>> import tca9548a_test2
Lux 46.6667
Temperature 26.1605
Temperature 26.1605
Lux  46.6667
Temperature 26.1796
Lux  46.25
Temperature 26.2198
Lux  46.25
Temperature 26.2603
Lux  46.6667

next run fails -- after soft reboot

Adafruit CircuitPython 7.0.0-alpha.2-673-gd79d68705 on 2021-05-25; Adafruit Feather RP2040 with rp2040
>>> import tca9548a_test2
Lux 46.6667
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "tca9548a_test2.py", line 18, in <module>
  File "adafruit_bme680.py", line 434, in __init__
ValueError: No I2C device at address: 77
>>> 

Note that it failed accessing the second sensor -- the bme680 -- it read from the bh1750
this is the code for accessing both

# SPDX-FileCopyrightText: 2021 ladyada for Adafruit Industries
# SPDX-License-Identifier: MIT

# This example shows using two TSL2491 light sensors attached to TCA9548A channels 0 and 1.
# Use with other I2C sensors would be similar.
import time
import board
import adafruit_tca9548a
import adafruit_bh1750
import adafruit_bme680


# Create the TCA9548A object and give it the I2C bus
tca = adafruit_tca9548a.TCA9548A(board.I2C())
# For each sensor, create it using the TCA9548A channel instead of the I2C object
bh = adafruit_bh1750.BH1750(tca[1])
print("Lux", bh.lux)
bme = adafruit_bme680.Adafruit_BME680_I2C(tca[4])
print("Temperature", bme.temperature)

# After initial setup, can just use sensors as normal.
while True:
    print("Temperature",bme.temperature)
    print("Lux ",bh.lux)
    time.sleep(1)

If I use a feather_m4 express, I have not seen any errors. Same code.

[jposada202020]

I did a similar with three sensors

Test Code

import time
import board
import adafruit_mma8451
import adafruit_tca9548a
import adafruit_bh1750
import adafruit_mpl3115a2
# import three_sensor_test

i2c = board.I2C()
tca = adafruit_tca9548a.TCA9548A(i2c)
sensor2 = adafruit_bh1750.BH1750(tca[4])
sensor = adafruit_mma8451.MMA8451(tca[1])
sensor3 = adafruit_mpl3115a2.MPL3115A2(tca[2])
sensor3.sealevel_pressure = 102250

while True:
    x, y, z = sensor.acceleration
    print("Acceleration: x={0:0.3f}m/s^2 y={1:0.3f}m/s^2 z={2:0.3f}m/s^2".format(x, y, z))
    time.sleep(1)
    print("%.2f Lux" % sensor2.lux)
    time.sleep(1)
    pressure = sensor3.pressure
    print("Pressure: {0:0.3f} pascals".format(pressure))

Results

Adafruit CircuitPython 6.2.0 on 2021-04-05; Adafruit Feather M4 Express with samd51j19
>>> import three_sensor_test
Acceleration: x=-0.350m/s^2 y=-0.546m/s^2 z=9.778m/s^2
95.00 Lux
Pressure: 100907.505 pascals
Acceleration: x=-0.350m/s^2 y=-0.536m/s^2 z=9.792m/s^2
96.25 Lux
Pressure: 100909.257 pascals
Acceleration: x=-0.330m/s^2 y=-0.522m/s^2 z=9.749m/s^2
95.83 Lux

Works all the time without any problem even with soft reset

RP2040

Same code in RP2040 could not find the sensor

[jposada202020]

This works without a problen when using the REPL on the RP2040

>>> import test_two_sensors
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "test_two_sensors.py", line 12, in <module>
  File "/lib/adafruit_mma8451.py", line 120, in __init__
ValueError: No I2C device at address: 1d
>>> 
soft reboot

Auto-reload is on. Simply save files over USB to run them or enter REPL to disable.

code.py output:
hello Jose

Code done running.

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

Adafruit CircuitPython 6.2.0 on 2021-04-05; Adafruit Feather RP2040 with rp2040
>>> import time
>>> import board
>>> import adafruit_mma8451
>>> import adafruit_tca9548a
>>> import adafruit_bh1750
>>> import adafruit_mpl3115a2
>>> i2c = board.I2C()
>>> tca = adafruit_tca9548a.TCA9548A(i2c)
>>> sensor2 = adafruit_bh1750.BH1750(tca[4])
>>> sensor = adafruit_mma8451.MMA8451(tca[1])
>>> sensor3 = adafruit_mpl3115a2.MPL3115A2(tca[2])
>>> sensor3.sealevel_pressure = 102250
>>> while True:
...     x, y, z = sensor.acceleration
...     print("Acceleration: x={0:0.3f}m/s^2 y={1:0.3f}m/s^2 z={2:0.3f}m/s^2".format(x, y, z))
...     time.sleep(1)
...     print("%.2f Lux" % sensor2.lux)
...     time.sleep(1)
...     pressure = sensor3.pressure
...     print("Pressure: {0:0.3f} pascals".format(pressure))
... 
Acceleration: x=-0.120m/s^2 y=-0.144m/s^2 z=9.869m/s^2
122.92 Lux
Pressure: 100828.254 pascals
Acceleration: x=-0.158m/s^2 y=-0.053m/s^2 z=9.807m/s^2
125.83 Lux

[jposada202020]

The BHT1750 is not the problem here as shown here

Adafruit CircuitPython 6.2.0 on 2021-04-05; Adafruit Feather RP2040 with rp2040
>>> import test_two_sensors
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "test_two_sensors.py", line 9, in <module>
  File "/lib/adafruit_mpl3115a2.py", line 135, in __init__
ValueError: No I2C device at address: 60
>>> import time
>>> import board
>>> import adafruit_mma8451
>>> import adafruit_tca9548a
>>> import adafruit_mpl3115a2
>>> i2c = board.I2C()
>>> tca = adafruit_tca9548a.TCA9548A(i2c)
>>> sensor = adafruit_mma8451.MMA8451(tca[1])
>>> sensor3 = adafruit_mpl3115a2.MPL3115A2(tca[2])
>>> sensor3.sealevel_pressure = 102250
>>> while True:
...     x, y, z = sensor.acceleration
...     print("Acceleration: x={0:0.3f}m/s^2 y={1:0.3f}m/s^2 z={2:0.3f}m/s^2".format(x, y, z))
...     time.sleep(1)
...     pressure = sensor3.pressure
...     print("Pressure: {0:0.3f} pascals".format(pressure))
... 
Acceleration: x=-0.105m/s^2 y=-0.326m/s^2 z=9.902m/s^2
Pressure: 100857.747 pascals
Acceleration: x=-0.110m/s^2 y=-0.239m/s^2 z=9.778m/s^2
Pressure: 100855.494 pascals
Acceleration: x=-0.120m/s^2 y=-0.244m/s^2 z=9.859m/s^2
Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
KeyboardInterrupt: 

[jposada202020]

Tested in the RP PIco same results

Adafruit CircuitPython 6.2.0 on 2021-04-05; Raspberry Pi Pico with rp2040
>>> import two_sensors_test
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "two_sensors_test.py", line 10, in <module>
  File "/lib/adafruit_mpl3115a2.py", line 136, in __init__
ValueError: No I2C device at address: 60
>>> 
soft reboot

Auto-reload is on. Simply save files over USB to run them or enter REPL to disable.

code.py output:
hello

Code done running.

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

Adafruit CircuitPython 6.2.0 on 2021-04-05; Raspberry Pi Pico with rp2040
>>> import time
>>> import board
>>> import busio
>>> import adafruit_mma8451
>>> import adafruit_tca9548a
>>> import adafruit_mpl3115a2
>>> i2c = busio.I2C(board.GP1, board.GP0)  # SCL, SDA
>>> tca = adafruit_tca9548a.TCA9548A(i2c)
>>> sensor = adafruit_mma8451.MMA8451(tca[1])
>>> sensor3 = adafruit_mpl3115a2.MPL3115A2(tca[2])
>>> sensor3.sealevel_pressure = 102250
>>> while True:
...     x, y, z = sensor.acceleration
...     print("Acceleration: x={0:0.3f}m/s^2 y={1:0.3f}m/s^2 z={2:0.3f}m/s^2".format(x, y, z))
...     time.sleep(1)
...     pressure = sensor3.pressure
...     print("Pressure: {0:0.3f} pascals".format(pressure))
... 
Acceleration: x=-0.139m/s^2 y=0.546m/s^2 z=9.831m/s^2
Pressure: 100858.498 pascals
Acceleration: x=-0.105m/s^2 y=0.532m/s^2 z=9.859m/s^2
Pressure: 100860.000 pascals
Acceleration: x=-0.120m/s^2 y=0.536m/s^2 z=9.826m/s^2
Traceback (most recent call last):
  File "<stdin>", line 4, in <module>
KeyboardInterrupt: 

[jerryneedell]

Now - I reversed the order in which the sensors are accessed
the first time -- both work again

Adafruit CircuitPython 7.0.0-alpha.2-673-gd79d68705 on 2021-05-25; Adafruit Feather RP2040 with rp2040
>>> import tca9548a_test2a
Temperature 26.0155
Lux 49.1667
Temperature 26.0833
Lux  49.1667
Temperature 26.1163
Lux  49.1667
Temperature 26.1507
Lux  49.1667
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "tca9548a_test2a.py", line 25, in <module>
KeyboardInterrupt: 
>>> 
soft reboot

the second time it fails, but on the second sensor again -- this time the bh1750 fails, it reads from the bme680

Auto-reload is on. Simply save files over USB to run them or enter REPL to disable.
code.py output:
Hello World!

Code done running.

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

Adafruit CircuitPython 7.0.0-alpha.2-673-gd79d68705 on 2021-05-25; Adafruit Feather RP2040 with rp2040
>>> import tca9548a_test2a
Temperature 26.0487
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "tca9548a_test2a.py", line 18, in <module>
  File "adafruit_bh1750.py", line 187, in __init__
ValueError: No I2C device at address: 23
>>> 

also I occasionally get this response ...

Adafruit CircuitPython 7.0.0-alpha.2-686-gf26528dfa on 2021-05-26; Adafruit Feather RP2040 with rp2040
>>> import tca9548a_test2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "tca9548a_test2.py", line 16, in <module>
  File "adafruit_bh1750.py", line 191, in __init__
  File "adafruit_bh1750.py", line 195, in initialize
  File "adafruit_bh1750.py", line 116, in __set__
  File "adafruit_bh1750.py", line 205, in _settings
  File "adafruit_bh1750.py", line 235, in _write
  File "adafruit_tca9548a.py", line 54, in unlock
OSError: [Errno 19] Unsupported operation
>>> 
soft reboot

[jerryneedell]

More information
I did some Logic analyzer captures running the test that access both sensors - bme680 first then bh1750 (note -- the failure is always on the second sensor if I swap the order - the issue is not with the bh1750)
I ran it with the featherM4 and then the feather rp2040
the M4 worked normal and this is the capture of the first transaction with the bh1750

this is the nature of the same transaction wthe the rp2040

You can see that the writes are different -- the m4 has an additional write to 0x70 ( the tca9548a) of data value 0x02 that is missing from the rp2040 write.
If I am not mistaken , this it the channel switch command that should be sent to the tca9548a to select channel 1 in this case. it is sent as part of try_lock https://github.com/adafruit/Adafruit_CircuitPython_TCA9548A/blob/master/adafruit_tca9548a.py#L49
and the channel is set during init to https://github.com/adafruit/Adafruit_CircuitPython_TCA9548A/blob/master/adafruit_tca9548a.py#L43
so channel 0 is 0x01, channel 1 is ox02 . channel 2 is 0x04 ....

This would explain the failure but it is not clear why the write is missing....
The game is afoot...

[jerryneedell]

just to confirm, I ran the test with the sensor order swapped on the rp2040 and the initial access to the bh1750 worked, but the first transaction with the bme680 failed -- here is the capture and you can see that the channel switch command is again missing.

and here is the run on the m4 showing the channel select to channel 4 0x10

[jposada202020]

Could you try it in the REPL? to see why in writing the code in the REPL it does work?

[jerryneedell]

it did not work from the REPL for me same failure

[jerryneedell]

but next time I tried it, it did work, but I did not capture it. One difference is I did not read from the bme680 in between. but I think it is just intermittent. I will do more runs do see if I can find a reproducible pattern.