I2C problems on ESP32-S2 after scan

[dhalbert]

Quoting from #9535 (comment):

I'm having a very similar issue with I2C on QT-PY-ESP32-S2. I've come at it all kinds of ways, with one or multiple I2C devices and varying the I2C bus speed from 10_000 to 400_000.

With these i2c devices:

• adafruit_ssd1306
  

• adafruit_seesaw (rotaryio: product number 4991)
  

When I do a i2c.scan() it never shows any devices, but I can "speak" to the rotaryio. When I enable the ssd1306, I get:

main.py output:
sys.implementation=(name='circuitpython', version=(9, 1, 1), _machine='Adafruit QT Py ESP32S2 with ESP32S2', _mpy=262)
I2C_FREQ       : 100000
I2C_DO_SCAN    : True
I2C_USE_SSD1306: True
I2C_USE_SEESAW : True
Scanning I2C addresses: []
Position: 0
cnt_loops = 16 / sec
Traceback (most recent call last):
  File "main.py", line 69, in <module>
  File "adafruit_ssd1306.py", line 219, in show
  File "adafruit_ssd1306.py", line 287, in write_framebuf
OSError: [Errno 116] ETIMEDOUT

If I never do the i2c.scan(), seesaw-rotaryio and ssd1306 appear to work fine (I've tried different instances of ssd1306 hardware).

In the case where I use only the seesaw-rotaryio and do i2c.scan(), the scan still shows no devices, I can communicate with the seesaw-rotario and my code speed decreases dramatically, e.g. 100+ loops/second becomes ~15 loops/second.

Code below. Can anyone shed some light on this?

Thanks,
Casa

# ==============================================================================
#
from micropython import const
import busio
import board
import sys
from adafruit_ticks import ticks_ms, ticks_add, ticks_less

I2C_FREQ = const(100_000)
I2C_DO_SCAN: bool = True
I2C_USE_SSD1306: bool = True
I2C_USE_SEESAW: bool = True

MS_ONE_SECOND = const(1000)

# ------------------------------------------------------------------------------
print(f"{sys.implementation=}")
print(f"I2C_FREQ       : {I2C_FREQ:6d}")
print(f"I2C_DO_SCAN    : {I2C_DO_SCAN}")
print(f"I2C_USE_SSD1306: {I2C_USE_SSD1306}")
print(f"I2C_USE_SEESAW : {I2C_USE_SEESAW}")

# ------------------------------------------------------------------------------
def print_I2C_Scan(i2c: busio.i2c) -> None:
    while not i2c.try_lock():
        pass
    print("Scanning I2C addresses:", [hex(i).upper() for i in i2c.scan()])
    i2c.unlock()

# ------------------------------------------------------------------------------
# Set up i2c0, OLED, seesaw rotaryio
#
i2c0 = busio.I2C(board.SCL, board.SDA, frequency=I2C_FREQ)

if I2C_USE_SSD1306:
    import adafruit_ssd1306
    ADDR = const(0x3C)
    WIDTH = const(128)
    HEIGHT = const(64)
    oled = adafruit_ssd1306.SSD1306_I2C(WIDTH, HEIGHT, i2c0, addr=ADDR)

if I2C_USE_SEESAW:
    from adafruit_seesaw import seesaw, rotaryio  #, digitalio
    seesaw = seesaw.Seesaw(i2c0, 0x36)
    encoder = rotaryio.IncrementalEncoder(seesaw)
    last_position = None

# ------------------------------------------------------------------------------
if I2C_DO_SCAN:
    print_I2C_Scan(i2c0)    # PROBLEM HERE

# ------------------------------------------------------------------------------
cnt_loops: int = 0
cnt_printed: int = 0
ms_target: int = ticks_add(ticks_ms(), MS_ONE_SECOND)
try:
    while True:
        cnt_loops += 1
        if not ticks_less(ticks_ms(), ms_target):

            ms_target = ticks_add(ticks_ms(), MS_ONE_SECOND)
            if cnt_printed < 10:
                cnt_printed += 1
                print(f"cnt_loops = {cnt_loops} / sec")
            cnt_loops = 0

            if I2C_USE_SSD1306:
                oled.fill(0)
                oled.show()
                # oled.line(X_MAX, Y_MAX, X_MIN, Y_MIN, 1)
                oled.vline(WIDTH // 2, 0, HEIGHT, 1)
                oled.show()

        if I2C_USE_SEESAW:
            if (position := -encoder.position) != last_position:
                last_position = position
                print("Position: {}".format(position))

except KeyboardInterrupt:
    print("Caught KeyboardInterrupt, exiting")

Originally posted by @Casa-Machinalia in #9535 (comment)

[dhalbert]

Could you re-test with 9.2.0-beta.0? Thanks. I am not seeing an issue now. But I don't have an SSD1306 connected, just a seesaw board.

[dhalbert]

I tested with an SSD1306 breakout. Interestingly, I have a very simple reproducer, on ESP32-S2 only, with 9.2.0-beta.0:

import board, adafruit_ssd1306
d = adafruit_ssd1306.SSD1306_I2C(128, 32, board.STEMMA_I2C(), addr=0x3c)

produces:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "adafruit_ssd1306.py", line 262, in __init__
  File "adafruit_ssd1306.py", line 103, in __init__
  File "adafruit_ssd1306.py", line 160, in init_display
  File "adafruit_ssd1306.py", line 219, in show
  File "adafruit_ssd1306.py", line 287, in write_framebuf
OSError: [Errno 116] ETIMEDOUT

There is no error on ESP32-S3 or RP2040.
Also, there is no error when testing on ESP32-S2 on 9.1.4.

[dhalbert]

I looked at this with a Saleae. On ESP32-S2, the I2C bus frequency is only 1.25 kHz (!), even though I requested 100 kHz. This is apparently due to some bug in ESP-IDF v5.3.1 (used in CircuitPython 9.2.0), which switched things around under the covers for the legacy I2C driver. It's fine in ESP-IDF v5.2.2, which is used in CircuitPython 9.1.4.

I reproduced the problem with an ESP-IDF-supplied example and opened an ESP-IDF issue:
espressif/esp-idf#14603

We want to move to the new ESP-IDF I2C driver, and that's possible now that esp-camera has updated. However, there are several open I2C issues for the new driver, so I'm not sure we want to move ahead yet if it may introduce new problems.

[Casa-Machinalia]

Thank you @dhalbert for wrangling this issue.

I updated to 9.2.0-beta.0 and retried my code with original h/w (QTPY-ESP32-S2, adafruit_ssd1306, adafruit_seesaw (rotaryio, #4991)

Result: Now fails even when I don't do a i2c.scan() -- this succeeded with v9.1.1

Auto-reload is on. Simply save files over USB to run them or enter REPL to disable.
main.py output:
sys.implementation=(name='circuitpython', version=(9, 2, 0, ''), _machine='Adafruit QT Py ESP32S2 with ESP32S2', _mpy=774)
I2C_FREQ       : 100000
I2C_DO_SCAN    : False
I2C_USE_SSD1306: True
I2C_USE_SEESAW : True
Traceback (most recent call last):
  File "main.py", line 89, in <module>
  File "adafruit_ssd1306.py", line 262, in __init__
  File "adafruit_ssd1306.py", line 103, in __init__
  File "adafruit_ssd1306.py", line 160, in init_display
  File "adafruit_ssd1306.py", line 219, in show
  File "adafruit_ssd1306.py", line 287, in write_framebuf
OSError: [Errno 116] ETIMEDOUT

Code done running.

Also tried I2C freq 40_000 and 10_000, no joy.

[dhalbert]

@tannewt started a branch with an update to the new ESP-IDF driver for I2C: https://github.com/tannewt/circuitpython/tree/idf5.2_i2c. I'm continuing with that on main. Got it working on ESP32-S3 just fine. On ESP32-S2 the clock speed is now correct, but I'm getting errors and crashes which I'm debugging.