There are three basic operating states to Espressif chips: normal, light sleep and
deep sleep.
Normal power usage is as you expect: you can use the chip and run code as you like -
connecting to WiFi, reading sensors, etc.
Light sleep is sort of a 'hibernation' - power usage is minimal and WiFi is
disconnected, but the internal clock and memory is kept. That means you can wake
up where you left off, in the middle of the code as desired. You'll still need to re-
initialize any external hardware that got disconnected, and WiFi, but it's often faster
than waking from a deep sleep
Deep sleep is the lowest power but the tradeoff is that all memory and state is lost -
the only thing that's running is the real time clock that can wake the chip up. When
woken up, the chip starts as if it was physically reset - from the beginning of the code.
This can be beneficial if you want to have a fresh start each time
A rough guideline is:
Normal power: 100mA+ can be as much power as need and spike during WiFi
connection
Light sleep: 2mA assuming all external hardware is de-powered
Deep sleep: 100uA assuming all external hardware is de-powered
There are two power pins on the ESP32-S3 TFT Feather: TFT_I2C_POWER , and
NEOPIXEL_POWER .
In CircuitPython and Arduino, both power pins are enabled by default, so if desired, y
ou must disable them manually in your code to reach lower power modes.
Here's a generic sketch we use for all our boards that has a macro-defined section for
enabling and disabling all external powered elements. For example, if there's a power
pin for NeoPixels, I2C port, TFT, etc...we turn that off before going into light or deep
sleep! This will minimize power usage
// SPDX-FileCopyrightText: 2022 Limor Fried for Adafruit Industries
//
// SPDX-License-Identifier: MIT
•
•
•
If you run into I2C, TFT, or NeoPixel power issues on Arduino, ensure you are
using the latest Espressif board support package. If you are still having issues,
you may need to manually pull the corresponding pin HIGH in your code.
©Adafruit Industries Page 24 of 263
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