feat(rmt): Add simple callback encoder

examples/peripherals/rmt/led_strip_simple_encoder/README.md

@@ -0,0 +1,56 @@
+| Supported Targets | ESP32 | ESP32-C3 | ESP32-C6 | ESP32-H2 | ESP32-P4 | ESP32-S2 | ESP32-S3 |
+| ----------------- | ----- | -------- | -------- | -------- | -------- | -------- | -------- |
+# RMT Transmit Example -- LED Strip
+
+(See the README.md file in the upper level 'examples' directory for more information about examples.)
+
+Almost any waveform can be generated by RMT peripheral, as long as a proper encoder is implemented. In this example, the simple callback RMT encoder is used to convert RGB pixels into format that can be recognized by hardware.
+
+This example shows how to drive an addressable LED strip [WS2812](https://cdn-shop.adafruit.com/datasheets/WS2812B.pdf) by implementing a callback that can be used by the simple callback RMT encoder.
+
+## How to Use Example
+
+### Hardware Required
+
+* A development board with any supported Espressif SOC chip (see `Supported Targets` table above)
+* A USB cable for Power supply and programming
+* A WS2812 LED strip
+
+Connection :
+
+```
+                              --- 5V
+                               |
+                               +
+RMT_LED_STRIP_GPIO_NUM +------ +---|>| (WS2812 LED strip)
+                        DI     +
+                               |
+                              --- GND
+```
+
+The GPIO number used in this example can be changed according to your board, by the macro `RMT_LED_STRIP_GPIO_NUM` defined in the [source file](main/led_strip_example_main.c). The number of LEDs can be changed as well by `EXAMPLE_LED_NUMBERS`.
+
+### 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 [Getting Started Guide](https://docs.espressif.com/projects/esp-idf/en/latest/get-started/index.html) for full steps to configure and use ESP-IDF to build projects.
+
+## Console Output
+
+```
+I (302) cpu_start: Starting scheduler on PRO CPU.
+I (0) cpu_start: Starting scheduler on APP CPU.
+I (323) example: Create RMT TX channel
+I (343) example: Create simple callback-based encoder
+I (353) example: Start LED rainbow chase
+```
+
+
+After you seeing this log, you should see a rainbow chasing demonstration pattern. To change the chasing speed, you can update the `EXAMPLE_ANGLE_INC_FRAME` value in [source file](main/led_strip_example_main.c). To change the density of colors, you can change `EXAMPLE_ANGLE_INC_LED` in the same file.
+
+## Troubleshooting
+
+For any technical queries, please open an [issue](https://github.com/espressif/esp-idf/issues) on GitHub. We will get back to you soon.