NeoPixel Ring + SH1107 auto_refresh stops working

[mikeysklar]

Forum issue regarding a small neopixel ring blocking the SH1107 FeatherWing from auto_refreshing.

When the led.show() for the Neopixel is commented out the OLED updates. If led.show() is left in the code the OLED stops updating within a few iterations.

The work around was to manually call display.refresh().

Working code provided. Comment out display.refresh() reproduces issue.

+------------------------------------+-------------------------+
|               Item                 |       Description       |
+------------------------------------+-------------------------+
| Adafruit Feather STM32F405         | WO# P4382C              |
| CircuitPython                      | 9.2.4                   |
| Library Bundle                     | 20250211                |
| Neopixel Ring 12-LED               | ADA# 1643               |
| OLED 128x64  FeatherWing           | ADA# 4650               |
+------------------------------------+-------------------------+

import time
import board
import displayio
from i2cdisplaybus import I2CDisplayBus
import adafruit_displayio_sh1107
from adafruit_display_text import label
import terminalio
import neopixel
import random

# Initialize sh1107 featherwing display
#time.sleep(2)

i2c = board.I2C()

WIDTH = 128
HEIGHT = 64

displayio.release_displays()
display_bus = I2CDisplayBus(i2c, device_address=0x3C)
display = adafruit_displayio_sh1107.SH1107(display_bus, width=WIDTH, height=HEIGHT)

splash = displayio.Group()
display.root_group = splash

# Palette
color_bitmap = displayio.Bitmap(128, 164, 1)
color_palette = displayio.Palette(1)  # i.e. one color
color_palette[0] = 0xFFFFFF

# Background
bg_sprite = displayio.TileGrid(color_bitmap, pixel_shader=color_palette, x=0, y=0)
splash.append(bg_sprite)
inner_bitmap = displayio.Bitmap(WIDTH, HEIGHT, 1)
inner_palette = displayio.Palette(1)
inner_palette[0] = 0x000000
inner_sprite = displayio.TileGrid(inner_bitmap, pixel_shader=inner_palette, x=0, y=0)
splash.append(inner_sprite)

# Build display line
line_1 = label.Label(terminalio.FONT, text="", scale=1, color=0xFFFFFF)
line_1.anchor_point = (0, 0)
line_1.anchored_position = (0, 3)
splash.append(line_1)

# Initialize NeoPixel ring
leds = neopixel.NeoPixel(board.D12, 12, brightness=0.1, auto_write=False)

i = 0
leds.fill((0, 0, 0))
leds.show()

while True:
    i += 1
    print(f"Pass {i}")

    # sh1107 display
    line_1.text = f"Pass {i}"

    # Update display manually to avoid blocking
    display.refresh()

    # neopixel ring update, but only every other loop iteration
    if i % 2 == 0:
        leds.fill((0, 0, 0))
    else:
        leds[0] = (255, 0, 0)

    leds.show()

    # Adjust timing for both display and NeoPixels
    time.sleep(0.25)