Added logic to time the interval between buffer fills, and bail out if the interval is more than +50% of what is expected

2 files changed, 27 insertions, 6 deletions

diff --git a/src/platforms/esp/32/clockless_rmt_esp32.cpp b/src/platforms/esp/32/clockless_rmt_esp32.cpp
index 20d2b217..907e37bf 100644
--- a/src/platforms/esp/32/clockless_rmt_esp32.cpp
+++ b/src/platforms/esp/32/clockless_rmt_esp32.cpp
@@ -32,9 +32,13 @@ CMinWait<50>   gWait;
 
 static bool gInitialized = false;
 
+// -- Bailout metric
+//    Keep track of how long it's been between buffer fills, and
+//    bail out on showing them if there's a big gap
+static uint32_t gLastFill[8];
+
 // -- SZG: For debugging purposes
 #if FASTLED_ESP32_SHOWTIMING == 1
-static uint32_t gLastFill[8];
 static int gTooSlow[8];
 static uint32_t gTotalTime[8];
 #endif
@@ -67,6 +71,13 @@ ESP32RMTController::ESP32RMTController(int DATA_PIN, int T1, int T2, int T3)
     gControllers[gNumControllers] = this;
     gNumControllers++;
 
+    // -- Expected number of CPU cycles between buffer fills
+    mCyclesPerFill = (T1 + T2 + T3) * PULSES_PER_FILL;
+
+    // -- If there is ever an interval greater than 1.5 times
+    //    the expected time, then bail out.
+    mMaxCyclesPerFill = mCyclesPerFill + mCyclesPerFill/2;
+
     mPin = gpio_num_t(DATA_PIN);
 }
 
@@ -274,9 +285,9 @@ void ESP32RMTController::startOnChannel(int channel)
 void ESP32RMTController::tx_start()
 {
     rmt_tx_start(mRMT_channel, true);
+    gLastFill[mRMT_channel] = __clock_cycles();
 
 #if FASTLED_ESP32_SHOWTIMING == 1
-    gLastFill[mRMT_channel] = __clock_cycles();
     gTooSlow[mRMT_channel] = 0;
     gTotalTime[mRMT_channel] = 0;
 #endif
@@ -323,9 +334,7 @@ void ESP32RMTController::doneOnChannel(rmt_channel_t channel, void * arg)
 //    next half of the RMT buffer with data.
 void IRAM_ATTR ESP32RMTController::interruptHandler(void *arg)
 {
-#if FASTLED_ESP32_SHOWTIMING == 1
     uint32_t now = __clock_cycles();
-#endif
 
     // -- The basic structure of this code is borrowed from the
     //    interrupt handler in esp-idf/components/driver/rmt.c
@@ -342,10 +351,14 @@ void IRAM_ATTR ESP32RMTController::interruptHandler(void *arg)
             if (intr_st & BIT(tx_next_bit)) {
                 // -- More to send on this channel
                 RMT.int_clr.val |= BIT(tx_next_bit);
-                pController->fillNext();
+                uint32_t delta = (now - gLastFill[channel]);
+                if (delta > pController->getMaxCyclesPerFill()) {
+                    doneOnChannel(rmt_channel_t(channel), 0);
+                } else {
+                    pController->fillNext();
+                }
 
 #if FASTLED_ESP32_SHOWTIMING == 1
-                uint32_t delta = (now - gLastFill[channel]);
                 if (delta > C_NS(50500)) {
                     gTooSlow[channel]++;
                 }
diff --git a/src/platforms/esp/32/clockless_rmt_esp32.h b/src/platforms/esp/32/clockless_rmt_esp32.h
index 604bd3d1..e8ee0f9c 100644
--- a/src/platforms/esp/32/clockless_rmt_esp32.h
+++ b/src/platforms/esp/32/clockless_rmt_esp32.h
@@ -192,6 +192,11 @@ private:
     rmt_item32_t   mZero;
     rmt_item32_t   mOne;
 
+    // -- Total expected time to send 32 bits
+    //    Each strip should get an interrupt roughly at this interval
+    uint32_t       mCyclesPerFill;
+    uint32_t       mMaxCyclesPerFill;
+
     // -- Pixel data
     uint32_t *     mPixelData;
     int            mSize;
@@ -215,6 +220,9 @@ public:
     //    member variables.
     ESP32RMTController(int DATA_PIN, int T1, int T2, int T3);
 
+    // -- Get max cycles per fill
+    uint32_t IRAM_ATTR getMaxCyclesPerFill() const { return mMaxCyclesPerFill; }
+
     // -- Get or create the pixel data buffer
     uint32_t * getPixelBuffer(int size_in_bytes);