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78 lines
2.9 KiB
Markdown
78 lines
2.9 KiB
Markdown
| Supported Targets | ESP32 | ESP32-C2 | ESP32-C3 | ESP32-C5 | ESP32-C6 | ESP32-C61 | ESP32-H2 | ESP32-P4 | ESP32-S2 | ESP32-S3 |
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| ----------------- | ----- | -------- | -------- | -------- | -------- | --------- | -------- | -------- | -------- | -------- |
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# eventfd example
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The example demonstrates the use of `eventfd()` to collect events from other tasks and ISRs in a
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`select()` based main loop. The example starts two tasks and installs a timer interrupt handler:
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1. The first task writes to the first `eventfd` periodically.
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2. The timer interrupt handler writes to the second `eventfd`.
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3. The second task collects the event from two fds with a `select()` loop.
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## How to use example
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### Hardware Required
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This example should be able to run on any commonly available ESP32, ESP32S2, ESP32S3 or ESP32C3 development board.
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### Configure the project
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```
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idf.py menuconfig
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```
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The default config will work.
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### Build and Flash
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Build the project and flash it to the board, then run monitor tool to view serial output:
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```
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idf.py -p PORT flash monitor
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```
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(Replace PORT with the name of the serial port to use.)
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(To exit the serial monitor, type ``Ctrl-]``.)
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See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.
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## Example Output
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The following log output should appear when the example runs (note that the bootloader log has been omitted).
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```
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I (4340) eventfd_example: Elapsed since test start: 2003 ms
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I (4340) eventfd_example: Select timeout
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I (4830) eventfd_example: Elapsed since test start: 2499 ms
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I (4830) eventfd_example: TimerEvent fd event triggered
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I (5830) eventfd_example: Elapsed since test start: 3493 ms
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I (5830) eventfd_example: Progress fd event triggered
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I (7330) eventfd_example: Elapsed since test start: 4999 ms
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I (7330) eventfd_example: TimerEvent fd event triggered
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I (7330) eventfd_example: =================================
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I (7340) eventfd_example: Select timeouted for 1 times
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I (7340) eventfd_example: Timer triggered for 2 times
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I (7350) eventfd_example: Progress triggered for 1 times
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I (7360) eventfd_example: =================================
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I (9330) eventfd_example: Elapsed since test start: 6993 ms
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I (9330) eventfd_example: Progress fd event triggered
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I (9830) eventfd_example: Elapsed since test start: 7499 ms
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I (9830) eventfd_example: TimerEvent fd event triggered
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I (11840) eventfd_example: Elapsed since test start: 9503 ms
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I (11840) eventfd_example: Select timeout
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I (12330) eventfd_example: Elapsed since test start: 9999 ms
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I (12330) eventfd_example: TimerEvent fd event triggered
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I (12330) eventfd_example: =================================
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I (12340) eventfd_example: Select timeouted for 2 times
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I (12340) eventfd_example: Timer triggered for 4 times
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I (12350) eventfd_example: Progress triggered for 2 times
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I (12360) eventfd_example: =================================
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```
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## Diagram
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The following diagram shows, with a timeline, the order of the events:
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