Merge pull request #1068 from WildernessLabs/feature/mcp2515

added error support to MCP2515
WildernessLabs · Aug 21, 2024 · 29141e2 · 29141e2
2 parents cf76c9a + 3a0927a
commit 29141e2
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Showing 6 changed files with 79 additions and 18 deletions.
diff --git a/Source/Meadow.Foundation.Peripherals/ICs.CAN.Mcp2515/Driver/Mcp2515.BitCalc.cs b/Source/Meadow.Foundation.Peripherals/ICs.CAN.Mcp2515/Driver/Mcp2515.BitCalc.cs
@@ -1,4 +1,5 @@
 using Meadow.Hardware;
+using System;
 
 namespace Meadow.Foundation.ICs.CAN;
 
@@ -41,7 +42,18 @@ public partial class Mcp2515
                 break;
 
             case CanOscillator.Osc_10MHz:
-                // TODO: add supported things here
+                switch (bitrate)
+                {
+                    //                    case CanBitrate.Can_125kbps:
+                    //                        return (0x03, 0xb8, 0x05);
+                    case CanBitrate.Can_250kbps:
+                        return (0x01, 0x90, 0x02);
+                    case CanBitrate.Can_500kbps:
+                        return (0x00, 0x90, 0x02);
+                    case CanBitrate.Can_1Mbps:
+                        return (0x00, 0x80, 0x00);
+                        // TODO: add supported things here
+                }
                 break;
 
             case CanOscillator.Osc_16MHz:
@@ -110,6 +122,39 @@ public partial class Mcp2515
 
         }
 
-        throw new System.NotSupportedException("Provided Bitrate and Oscillator frequency is not supported");
+        // if we don't have a fixed, pre-calculated value, try to calculate one
+        var freq = oscillator switch
+        {
+            CanOscillator.Osc_8MHz => 8_000_000,
+            CanOscillator.Osc_10MHz => 10_000_000,
+            CanOscillator.Osc_16MHz => 16_000_000,
+            CanOscillator.Osc_20MHz => 20_000_000,
+            _ => throw new NotSupportedException(),
+        };
+
+        return CalculateConfigForOscillatorAndBitrate((int)oscillator, (int)bitrate);
+    }
+
+    private (byte CFG1, byte CFG2, byte CFG3) CalculateConfigForOscillatorAndBitrate(int oscillatorFreq, int bitRate)
+    {
+        int TQ = 16; // Assume 16 time quanta per bit time
+        int PropSeg = 3; // Propagation segment
+        int PhaseSeg1 = 5; // Phase Segment 1
+        int PhaseSeg2 = 5; // Phase Segment 2
+        int SJW = 1; // Synchronization Jump Width (1 TQ)
+
+        // Calculate Baud Rate Prescaler (BRP)
+        int brp = (oscillatorFreq / (2 * bitRate * TQ)) - 1;
+        if (brp < 0 || brp > 63) // BRP must fit in 6 bits
+        {
+            throw new ArgumentOutOfRangeException("Cannot calculate BRP for the given oscillator frequency and bitrate.");
+        }
+
+        // Calculate CNF1, CNF2, CNF3
+        var cfg1 = (byte)(((SJW - 1) << 6) | (brp & 0x3F)); // SJW is 2 bits, BRP is 6 bits
+        var cfg2 = (byte)(0x80 | ((PhaseSeg1 - 1) << 3) | (PropSeg - 1)); // Set SAM = 1 for single sampling
+        var cfg3 = (byte)(PhaseSeg2 - 1); // PhaseSeg2
+
+        return (cfg1, cfg2, cfg3);
     }
 }
diff --git a/Source/Meadow.Foundation.Peripherals/ICs.CAN.Mcp2515/Driver/Mcp2515.CanBus.cs b/Source/Meadow.Foundation.Peripherals/ICs.CAN.Mcp2515/Driver/Mcp2515.CanBus.cs
@@ -12,7 +12,8 @@ public class Mcp2515CanBus : ICanBus
 
         /// <inheritdoc/>
         public event EventHandler<ICanFrame>? FrameReceived;
-        public event EventHandler<byte>? BusError;
+        /// <inheritdoc/>
+        public event EventHandler<CanErrorInfo>? BusError;
 
         private Mcp2515 Controller { get; }
 
@@ -105,8 +106,20 @@ private void OnInterruptPortChanged(object sender, DigitalPortResult e)
                     }
                     break;
                 case InterruptCode.Error:
-                    var errors = Controller.ReadRegister(Register.EFLG)[0];
-                    BusError?.Invoke(this, errors);
+                    if (BusError != null)
+                    {
+                        var errors = Controller.ReadRegister(Register.EFLG)[0];
+                        // read the error counts
+                        var tec = Controller.ReadRegister(Register.TEC)[0];
+                        var rec = Controller.ReadRegister(Register.REC)[0];
+                        BusError.Invoke(this, new CanErrorInfo
+                        {
+                            ReceiveErrorCount = rec,
+                            TransmitErrorCount = tec
+                        });
+                        // clear the error interrupt
+                        Controller.ClearInterrupt(InterruptFlag.ERRIF | InterruptFlag.MERRF);
+                    }
                     break;
             }
         }

diff --git a/Source/Meadow.Foundation.Peripherals/ICs.CAN.Mcp2515/Driver/Mcp2515.Enums.cs b/Source/Meadow.Foundation.Peripherals/ICs.CAN.Mcp2515/Driver/Mcp2515.Enums.cs
@@ -6,10 +6,10 @@ public partial class Mcp2515
 {
     public enum CanOscillator
     {
-        Osc_8MHz,
-        Osc_10MHz,
-        Osc_16MHz,
-        Osc_20MHz,
+        Osc_8MHz = 8_000_000,
+        Osc_10MHz = 10_000_000,
+        Osc_16MHz = 16_000_000,
+        Osc_20MHz = 20_000_000,
     }
 
     private enum Register : byte
@@ -143,8 +143,8 @@ private enum Control : byte
     private enum Status : byte
     {
         NONE = 0,
-        RX0IF = (1 << 0),
-        RX1IF = (1 << 1)
+        RX0IF = 1 << 0,
+        RX1IF = 1 << 1
     }
 
     private enum Result : byte

diff --git a/Source/Meadow.Foundation.Peripherals/ICs.CAN.Mcp2515/Driver/Mcp2515.cs b/Source/Meadow.Foundation.Peripherals/ICs.CAN.Mcp2515/Driver/Mcp2515.cs
@@ -83,9 +83,7 @@ private void Initialize(CanBitrate bitrate, CanOscillator oscillator)
 
         if (InterruptPort != null)
         {
-            // TODO: add error condition handling
-            ConfigureInterrupts(InterruptEnable.RXB0 | InterruptEnable.RXB1 | InterruptEnable.ERR | InterruptEnable.MSG_ERR);
-            //ConfigureInterrupts(InterruptEnable.RXB0 | InterruptEnable.RXB1);
+            ConfigureInterrupts(InterruptEnable.RXB0 | InterruptEnable.RXB1 | InterruptEnable.ERR);
             ClearInterrupt((InterruptFlag)0xff);
         }
         else
@@ -192,15 +190,15 @@ private void WriteFrame(ICanFrame frame, int bufferNumber)
             {
                 // put the frame id into a buffer (0-2)
                 var sidh = (byte)(sdf.ID >> 3);
-                var sidl = (byte)(sdf.ID << 5 & 0xe0);
+                var sidl = (byte)((sdf.ID << 5) & 0xe0);
                 WriteRegister(ctrl_reg + 1, sidh);
                 WriteRegister(ctrl_reg + 2, sidl);
             }
             else if (frame is StandardRtrFrame srf)
             {
                 // put the frame id into a buffer (0-2)
                 var sidh = (byte)(srf.ID >> 3);
-                var sidl = (byte)(srf.ID << 5 & 0xe0);
+                var sidl = (byte)((srf.ID << 5) & 0xe0);
                 WriteRegister(ctrl_reg + 1, sidh);
                 WriteRegister(ctrl_reg + 2, sidl);
 

diff --git a/Source/Meadow.Foundation.Peripherals/ICs.IOExpanders.PCanBasic/Driver/PCanBus.cs b/Source/Meadow.Foundation.Peripherals/ICs.IOExpanders.PCanBasic/Driver/PCanBus.cs
@@ -10,6 +10,8 @@ public class PCanBus : ICanBus
 {
     /// <inheritdoc/>
     public event EventHandler<ICanFrame>? FrameReceived;
+    /// <inheritdoc/>
+    public event EventHandler<CanErrorInfo>? BusError;
 
     /// <inheritdoc/>
     public CanAcceptanceFilterCollection AcceptanceFilters { get; } = new(5);

diff --git a/Source/Meadow.Foundation.Peripherals/ICs.IOExpanders.PCanBasic/Driver/PCanFdBus.cs b/Source/Meadow.Foundation.Peripherals/ICs.IOExpanders.PCanBasic/Driver/PCanFdBus.cs
@@ -4,6 +4,11 @@ namespace ICs.IOExpanders.PCanBasic;
 
 public class PCanFdBus : ICanBus
 {
+    /// <inheritdoc/>
+    public event EventHandler<ICanFrame>? FrameReceived;
+    /// <inheritdoc/>
+    public event EventHandler<CanErrorInfo>? BusError;
+
     internal PCanFdBus(PCanConfiguration configuration)
     {
         throw new NotImplementedException();
@@ -13,8 +18,6 @@ internal PCanFdBus(PCanConfiguration configuration)
 
     public CanAcceptanceFilterCollection AcceptanceFilters => throw new NotImplementedException();
 
-    public event EventHandler<ICanFrame>? FrameReceived;
-
     public void ClearReceiveBuffers()
     {
         throw new NotImplementedException();