fix: end frame for SK9822 LEDs

RoboticsBrno · Dec 27, 2024 · 3bbc35f · 3bbc35f
1 parent dd49716
commit 3bbc35f
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Showing 3 changed files with 8 additions and 5 deletions.
diff --git a/library.json b/library.json
@@ -14,7 +14,7 @@
       "maintainer": true
     }
   ],
-  "version": "3.1.4",
+  "version": "3.1.5",
   "frameworks": ["arduino", "espidf"],
   "platforms": "espressif32"
 }
diff --git a/library.properties b/library.properties
@@ -1,5 +1,5 @@
 name=SmartLeds
-version=3.1.4
+version=3.1.5
 author=Jan Mrázek
 maintainer=Jan Mrázek <email@honzamrazek.cz>
 sentence=Simple & intuitive way to drive various smart LEDs on ESP32.

diff --git a/src/SmartLeds.h b/src/SmartLeds.h
@@ -200,6 +200,7 @@ class SmartLed {
 #define _SMARTLEDS_SPI_DMA_CHAN 1
 #endif
 
+// Can also handle SK9822
 class Apa102 {
 public:
     struct ApaRgb {
@@ -256,7 +257,7 @@ class Apa102 {
         ret = spi_bus_add_device(_SMARTLEDS_SPI_HOST, &devcfg, &_spi);
         assert(ret == ESP_OK);
 
-        std::fill_n(_finalFrame, FINAL_FRAME_SIZE, 0xFFFFFFFF);
+        std::fill_n(_finalFrame, FINAL_FRAME_SIZE, 0);
     }
 
     ~Apa102() {
@@ -304,8 +305,10 @@ class Apa102 {
         spi_device_queue_trans(_spi, _transactions + 1, portMAX_DELAY);
         _transCount = 2;
         // End frame
-        for (int i = 0; i != 1 + _count / 32 / FINAL_FRAME_SIZE; i++) {
-            _transactions[2 + i].length = 32 * FINAL_FRAME_SIZE;
+        // https://cpldcpu.com/2016/12/13/sk9822-a-clone-of-the-apa102/ - "Unified protocol"
+        const int end_bits = 32 + (_count/2 + 1);
+        for (int i = 0; i < end_bits; i += 32 * FINAL_FRAME_SIZE) {
+            _transactions[2 + i].length = std::min(32 * FINAL_FRAME_SIZE, end_bits - i);
             _transactions[2 + i].tx_buffer = _finalFrame;
             spi_device_queue_trans(_spi, _transactions + 2 + i, portMAX_DELAY);
             _transCount++;