Merge pull request #1113 from WildernessLabs/bug/pca-9685

bug fix for PCA9685 100% on
WildernessLabs · Jan 11, 2025 · 2812789 · 2812789
2 parents a48e654 + db085a5
commit 2812789
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Showing 2 changed files with 43 additions and 5 deletions.
diff --git a/Source/Meadow.Foundation.Peripherals/ICs.IOExpanders.Pca9685/Driver/Pca9685.PwmPort.cs b/Source/Meadow.Foundation.Peripherals/ICs.IOExpanders.Pca9685/Driver/Pca9685.PwmPort.cs
@@ -126,6 +126,32 @@ internal PwmPort(
         /// </summary>
         public void Start()
         {
+            if (DutyCycle >= 1.0)
+            {
+                // Special case for always ON - set bit 4 of ON_H register
+                if (Inverted)
+                {
+                    controller.SetPwm(portNumber, 0, 4096);  // This signals always-off
+                }
+                else
+                {
+                    controller.SetPwm(portNumber, 4096, 0);  // 4096 signals always-on
+                }
+            }
+            else if (DutyCycle <= 0)
+            {
+                // Special case for always OFF
+                if (Inverted)
+                {
+                    controller.SetPwm(portNumber, 4096, 0);  // This signals always-off
+                }
+                else
+                {
+                    controller.SetPwm(portNumber, 0, 4096);  // This signals always-off
+                }
+            }
+
+
             // DEV NOTE: according to the data sheetdiagrams (starting on page 17)
             //           You tell it at what "tick" to turn on (from the start) and what tick to turn off
             //           Since it's a repeated tick, we can just always turn on a 0 (start of the cycle)

diff --git a/Source/Meadow.Foundation.Peripherals/ICs.IOExpanders.Pca9685/Driver/Pca9685.cs b/Source/Meadow.Foundation.Peripherals/ICs.IOExpanders.Pca9685/Driver/Pca9685.cs
@@ -128,14 +128,24 @@ private void SetPwm(byte pin, int on, int off)
             throw new ArgumentException("Value has to be between 0 and 15", nameof(pin));
         }
 
-        if (on is < 0 or > 4096)
+        // Special case for fully on
+        if (off == 4096)
         {
-            throw new ArgumentException("Value has to be between 0 and 4096", nameof(on));
+            on = 4096;  // Set the special "fully on" bit
+            off = 0;
         }
-
-        if (off is < 0 or > 4096)
+        else
         {
-            throw new ArgumentException("Value has to be between 0 and 4096", nameof(off));
+            // Normal validation for PWM operation
+            if (on is < 0 or > 4096)
+            {
+                throw new ArgumentException("Value has to be between 0 and 4096", nameof(on));
+            }
+
+            if (off is < 0 or > 4096)
+            {
+                throw new ArgumentException("Value has to be between 0 and 4096", nameof(off));
+            }
         }
 
         Write((byte)(Registers.Led0OnL + (4 * pin)), (byte)(on & 0xFF), (byte)(on >> 8), (byte)(off & 0xFF), (byte)(off >> 8));
@@ -208,6 +218,8 @@ public IPwmPort CreatePwmPort(IPin pin, Frequency frequency, float dutyCycle = 0
     {
         var portNumber = (byte)pin.Key;
 
+        Resolver.Log.Trace($"CreatePwmPort on port {portNumber} at {frequency.Hertz:N0}Hz and DC {dutyCycle:N2}", "Pca9685");
+
         if (portNumber is < 0 or > 15)
         {
             throw new ArgumentException("Value must be between 0 and 15", nameof(portNumber));