Add interface2

interface2/firmware/include/message.h

@@ -0,0 +1,60 @@
+// 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>
+
+enum MessageReceiverError {
+    MESSAGE_RECEIVER_ERROR_DATA_OVERFLOW,
+    MESSAGE_RECEIVER_ERROR_MESSAGE_OVERFLOW,
+    MESSAGE_RECEIVER_ERROR_TIMEOUT
+};
+
+enum MessageReceiverState {
+    MESSAGE_RECEIVER_STATE_WAIT_START,
+    MESSAGE_RECEIVER_STATE_DATA,
+    MESSAGE_RECEIVER_STATE_ESCAPE,
+    MESSAGE_RECEIVER_STATE_AVAILABLE,
+    MESSAGE_RECEIVER_STATE_DATA_OVERFLOW,
+    MESSAGE_RECEIVER_STATE_MESSAGE_OVERFLOW
+};
+
+class MessageReceiver
+{
+public:
+    MessageReceiver(volatile uint8_t *buffer, size_t bufferSize,
+            void (*messageCallback)(const uint8_t *, size_t),
+            void (*errorCallback)(MessageReceiverError));
+
+    void load(const uint8_t *buffer, size_t bufferCount);
+    bool dispatch();
+
+private:
+    uint32_t _timeout;
+    volatile uint32_t _lastReceiveTime;
+    volatile uint8_t *_buffer;
+    size_t _bufferSize;
+    volatile size_t _bufferCount;
+    volatile MessageReceiverState _state;
+    void (*_messageCallback)(const uint8_t *, size_t);
+    void (*_errorCallback)(MessageReceiverError);
+};
+
+class MessageSender
+{
+public:
+    static bool send(const uint8_t *buffer, size_t bufferCount);
+};