esp-idf/examples/system/ulp_riscv/ds18b20_onewire/README.md

Supported Targets	ESP32-S2

ULP-RISC-V DS18B20 Temperature Sensor OneWire Communication

This example demonstrates how to program the ULP-RISC-V co-processor to read temperature from a DS18B20 temperature sensor over 1-Wire. When the measurement exceeds the limit set(32.5 degrees) the co-processor will wake up the main CPU from deep-sleep and the main CPU will print the temperature measurement.

Hardware Required

• A development board with a SOC which has a RISC-V ULP coprocessor (e.g., ESP32-S2 Saola)
• A USB cable for power supply and programming
• A DS18B20 temperature sensor

Example connection :

ESP Dev-kit	DS18B20
GPIO4	DQ
VCC 3.3V	VDD
GND	GND

Example output

Not a ULP wakeup, initializing it!
Entering in deep sleep

...

ULP-RISC-V woke up the main CPU, temperature is above set limit!
ULP-RISC-V read temperature is 32.562500
Entering in deep sleep

...

ULP-RISC-V woke up the main CPU, temperature is above set limit!
ULP-RISC-V read temperature is 33.000000
Entering in deep sleep