esp-idf/examples/peripherals/timer_group/legacy_driver

Supported Targets	ESP32	ESP32-C2	ESP32-C3	ESP32-C5	ESP32-C6	ESP32-H2	ESP32-P4	ESP32-S2	ESP32-S3

Example: General Purpose Timer

This example uses the legacy timer group driver to generate timer interrupts with and without auto-reload. But we highly recommend you to use the new GPTimer Driver in your new projects.

How to Use Example

Hardware Required

• A development board with ESP SoC (e.g., ESP32-DevKitC, ESP-WROVER-KIT, etc.)
• A USB cable for Power supply and programming

Build and Flash

Run idf.py -p PORT flash monitor to build, flash and monitor the project.

(To exit the serial monitor, type Ctrl-].)

See the ESP-IDF Getting Started Guide for all the steps to configure and use the ESP-IDF to build projects.

Example Output

I (0) cpu_start: Starting scheduler on APP CPU.
I (325) example: Init timer with auto-reload
I (835) example: Timer auto reloaded, count value in ISR: 3
I (1335) example: Timer auto reloaded, count value in ISR: 3
I (1835) example: Timer auto reloaded, count value in ISR: 3
I (2335) example: Timer auto reloaded, count value in ISR: 3
I (2335) example: Init timer without auto-reload
I (2835) example: Timer alarmed at 500003
I (3335) example: Timer alarmed at 1000003
I (3835) example: Timer alarmed at 1500003
I (4335) example: Timer alarmed at 2000003

Functionality Overview

• Configure one timer with auto-reload enabled, alarm period set to 0.5s
• On reaching the interval value the timer will generate an alarm
• The timer will reload with initial count value on alarm, by hardware
• Reconfigure the timer with auto-reload disabled, initial alarm value set to 0.5s
• The timer keeps incrementing and in the alarm callback, the software reconfigures its alarm value by increasing 0.5s
• The main task will print the count value that captured in the alarm callback

Troubleshooting

For any technical queries, please open an issue on GitHub. We will get back to you soon.