feat(led_strip): update rmt example to guide the use of DMA

Author: zackees

led_strip/examples/led_strip_rmt_ws2812/main/led_strip_rmt_ws2812_main.c

@@ -10,10 +10,23 @@
 #include "esp_log.h"
 #include "esp_err.h"
 
-// GPIO assignment
-#define LED_STRIP_GPIO_PIN  2
+// Set to 1 to use DMA for driving the LED strip, 0 otherwise
+// Please note the RMT DMA feature is only available on chips e.g. ESP32-S3/P4
+#define LED_STRIP_USE_DMA  0
+
+#if LED_STRIP_USE_DMA
+// Numbers of the LED in the strip
+#define LED_STRIP_LED_COUNT 256
+#define LED_STRIP_MEMORY_BLOCK_WORDS 1024 // this determines the DMA block size
+#else
 // Numbers of the LED in the strip
 #define LED_STRIP_LED_COUNT 24
+#define LED_STRIP_MEMORY_BLOCK_WORDS 0 // let the driver choose a proper memory block size automatically
+#endif // LED_STRIP_USE_DMA
+
+// GPIO assignment
+#define LED_STRIP_GPIO_PIN  2
+
 // 10MHz resolution, 1 tick = 0.1us (led strip needs a high resolution)
 #define LED_STRIP_RMT_RES_HZ  (10 * 1000 * 1000)
 
@@ -36,9 +49,9 @@ led_strip_handle_t configure_led(void)
     led_strip_rmt_config_t rmt_config = {
         .clk_src = RMT_CLK_SRC_DEFAULT,        // different clock source can lead to different power consumption
         .resolution_hz = LED_STRIP_RMT_RES_HZ, // RMT counter clock frequency
-        .mem_block_symbols = 0,               // the memory size of each RMT channel, 0 lets the driver decide.
+        .mem_block_symbols = LED_STRIP_MEMORY_BLOCK_WORDS, // the memory block size used by the RMT channel
         .flags = {
-            .with_dma = false, // DMA feature is available on chips like ESP32-S3/P4
+            .with_dma = LED_STRIP_USE_DMA,     // Using DMA can improve performance when driving more LEDs
         }
     };