Fix DMX reads to disallow ASC packets

ASC is "Alternate Start Code".

Author: ssilverman

Deevstock/DSGrid/control_tdmx.h

@@ -15,7 +15,7 @@
 CMSGEQ7<true, MSGEQ7_RESET_PIN, MSGEQ7_STROBE_PIN, AUDIO_LEFT_PIN, AUDIO_RIGHT_PIN> MSGEQ7;
 
 qindesign::teensydmx::Receiver dmxRx{Serial1};
-uint8_t dmxRxBuf[512];  // Buffer up to 512 channels
+uint8_t dmxRxBuf[513];  // Buffer up to 513 channels, including the start code
 
 void InitMSGEQ7() { 
   MSGEQ7.begin();
@@ -33,7 +33,7 @@ void controlSetup() {
 }
 
 int getValue(int chan, int minV, int maxV) {
-  return map(dmxRxBuf[(chan - 1)], 0, 255, minV, maxV);
+  return map(dmxRxBuf[chan], 0, 255, minV, maxV);
 }
 
 
@@ -58,10 +58,9 @@ int right[7];
 void controlLoop() {
   int gPatternCount = 32; // FIXME
 
-  // Read up to 4 bytes (3rd param) starting from channel 1 (2nd param)
-  // Channel 0 is the start code
-  int read = dmxRx.read(dmxRxBuf, 1, 4);
-  if (read == 4) {
+  // Read up to 5 bytes (4 channels) starting from channel 0 (start code)
+  int read = dmxRx.read(dmxRxBuf, 0, 5);
+  if (read == 5 && dmxRxBuf[0] == 0) {  // Ensure start code is zero
     EVERY_N_SECONDS( 2 ) {
       Serial.printf("Brighness: %u\n", getValue(1, 0, 255)); // Dimmer data for Channel 1
     }

Deevstock/DeevstockDMX/DeevstockDMX.ino

@@ -37,7 +37,7 @@ const bool    kMatrixSerpentineLayout = true;
 // **********************************************************************************************************
 
 qindesign::teensydmx::Receiver dmxRx{Serial1};
-uint8_t dmxRxBuf[6];  // Buffer up to 512 channels
+uint8_t dmxRxBuf[513];  // Buffer up to 513 channels, including the start code
 
 CRGB leds[NUM_LEDS];
 CRGB ledsAudio[NUM_AUDIO_LEDS];
@@ -239,30 +239,29 @@ elapsedMillis elapsed;
 int pattern = 0;
 void loop()
 {
-  // Read up to 6 bytes (3rd param) starting from channel 1 (2nd param)
-  // Channel 0 is the start code
-  int read = dmxRx.readPacket(dmxRxBuf, 1, 6);
-  if (read == 6) {
+  // Read up to 7 bytes (6 channels) starting from channel 0 (start code)
+  int read = dmxRx.readPacket(dmxRxBuf, 0, 7);
+  if (read == 7 && dmxRxBuf[0] == 0) {  // Ensure start code is zero
     led = !led;
     digitalWrite(LED_BUILTIN, led);
-    int b = dmxRxBuf[0]; // brightness = 1
+    int b = dmxRxBuf[1]; // brightness = 1
     if (b != BRIGHTNESS) {
       BRIGHTNESS = b;
       FastLED.setBrightness(BRIGHTNESS);
       Serial.printf("Brightness: %u\n", BRIGHTNESS);
     }
-    STEPS = dmxRxBuf[1]; // steps = 2
-    SPEEDO = dmxRxBuf[2]; //speed = 3
-    FADE = dmxRxBuf[3]; // fade = 4
-    int p = dmxRxBuf[4]; // pattern = 5
+    STEPS = dmxRxBuf[2]; // steps = 2
+    SPEEDO = dmxRxBuf[3]; //speed = 3
+    FADE = dmxRxBuf[4]; // fade = 4
+    int p = dmxRxBuf[5]; // pattern = 5
     pattern = map(p, 0, 255, 0, (gPatternCount - 1));
     if(p > (gPatternCount - 1)) { 
       p = 0;
     }
     else {
       pattern = p;
     }
-    currentPalette = palettes[map(dmxRxBuf[5], 0, 255, 0, (paletteCount - 1))]; // channel 6
+    currentPalette = palettes[map(dmxRxBuf[6], 0, 255, 0, (paletteCount - 1))]; // channel 6
 //    EVERY_N_SECONDS( 2 ) {
 //      Serial.println(p);
 //      Serial.print("b=");