Add interface2

interface2/firmware/include/coax.h

@@ -0,0 +1,118 @@
+// Copyright (c) 2020, Andrew Kay
+//
+// Permission to use, copy, modify, and/or distribute this software for any
+// purpose with or without fee is hereby granted, provided that the above
+// copyright notice and this permission notice appear in all copies.
+//
+// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+
+#pragma once
+
+#include <cstdint>
+#include <cstddef>
+
+#define COAX_ERROR_TX_RECEIVER_ACTIVE -1
+#define COAX_ERROR_TX_UNDERFLOW -2
+
+#define COAX_ERROR_RX_LOSS_OF_MID_BIT_TRANSITION -1
+#define COAX_ERROR_RX_PARITY -2
+#define COAX_ERROR_RX_INVALID_END_SEQUENCE -4
+#define COAX_ERROR_RX_OVERFLOW -8
+#define COAX_ERROR_RX_UNKNOWN -513
+
+#define COAX_ERROR_NOT_INITIALIZED -1024
+
+enum class CoaxParity
+{
+    Odd = 0,
+    Even = 1
+};
+
+class SPICoaxTransceiver;
+
+class Coax
+{
+public:
+    Coax(SPICoaxTransceiver &spiCoaxTransceiver, CoaxParity parity,
+            volatile uint16_t *buffer, size_t bufferSize);
+
+    bool init();
+
+    void reset();
+
+    int transmit(const uint16_t *buffer, size_t bufferCount);
+    int receive(uint16_t *buffer, size_t bufferSize, uint16_t timeout);
+
+    void handleInterrupt();
+
+private:
+    SPICoaxTransceiver &_spiCoaxTransceiver;
+    CoaxParity _parity;
+
+    bool _isInitialized;
+
+    volatile enum {
+        COAX_INTERRUPT_STATE_IDLE,
+        COAX_INTERRUPT_STATE_DISABLED,
+        COAX_INTERRUPT_STATE_RECEIVING,
+        COAX_INTERRUPT_STATE_RECEIVED,
+        COAX_INTERRUPT_STATE_ERROR
+    } _interruptState = COAX_INTERRUPT_STATE_DISABLED;
+
+    volatile uint16_t *_buffer;
+    size_t _bufferSize;
+    volatile size_t _bufferCount = 0;
+    volatile int _error = 0;
+};
+
+#define COAX_REGISTER_STATUS 0x1
+#define COAX_REGISTER_STATUS_RX_ERROR 0x40
+#define COAX_REGISTER_STATUS_RX_ACTIVE 0x20
+#define COAX_REGISTER_STATUS_TX_COMPLETE 0x08
+#define COAX_REGISTER_STATUS_TX_ACTIVE 0x04
+
+#define COAX_REGISTER_CONTROL 0x2
+#define COAX_REGISTER_CONTROL_LOOPBACK 0x01
+#define COAX_REGISTER_CONTROL_TX_PARITY 0x08
+#define COAX_REGISTER_CONTROL_RX_PARITY 0x40
+
+#define COAX_REGISTER_DEVICE_ID 0xf
+
+class SPICoaxTransceiver
+{
+public:
+    SPICoaxTransceiver();
+
+    bool init();
+
+    void reset();
+
+    uint8_t readRegister(uint8_t index);
+    void writeRegister(uint8_t index, uint8_t value, uint8_t mask);
+
+    int transmit(const uint16_t *buffer, size_t bufferCount);
+    int receive(uint16_t *buffer, size_t bufferSize);
+
+    void setLoopback(bool loopback);
+    void setTXParity(CoaxParity parity);
+    void setRXParity(CoaxParity parity);
+
+    inline bool isTXComplete()
+    {
+        return readRegister(COAX_REGISTER_STATUS) & COAX_REGISTER_STATUS_TX_COMPLETE;
+    }
+
+    inline bool isRXActive()
+    {
+        return readRegister(COAX_REGISTER_STATUS) & COAX_REGISTER_STATUS_RX_ACTIVE;
+    };
+
+private:
+    void spiTransfer(const uint8_t *transmitBuffer, uint8_t *receiveBuffer, size_t count);
+};