1 files changed, 97 insertions, 0 deletions

diff --git a/martin/door/src/hcs200.h b/martin/door/src/hcs200.h
new file mode 100644
index 0000000..95aa18b
--- /dev/null
+++ b/martin/door/src/hcs200.h
@@ -0,0 +1,97 @@
+#pragma once
+
+#include <functional>
+#include <Print.h>
+
+class HCS200_Keycode
+{
+  public:
+    /** Bit masks to determine which button was pressed on the keyfob.
+     * NOTE: the bit position does not match the button number
+     */
+    enum ButtonMask
+      : unsigned char
+    {
+        BM_S3 = 0x1,
+        BM_S0 = 0x2,
+        BM_S1 = 0x4,
+        BM_S2 = 0x8
+    };
+
+    void print(Print &stream);
+    void send(std::function<void(int)> setOutput);
+
+  private:
+    void send(bool value, std::function<void(int)> setOutput);
+
+  public:
+    uint32_t encrypted;
+    uint32_t serial;
+    unsigned char buttons;
+    bool lowbat;
+};
+
+class HCS200
+{
+  public:
+    enum RxState
+    {
+      RS_NOSYNC = 0,      // Receiver is inactive
+      RS_PREAMBLE_START,
+      RS_PREAMBLE_LOW,
+      RS_PREAMBLE_HIGH,
+      RS_PREAMBLE_HEADER,
+      RS_DATA,            // DATA is being received
+      RS_COMPLETED        // Receive complete
+    };
+
+    void on_isr(uint8_t value);
+    void reset();
+    bool decode(struct HCS200_Keycode &out);
+    void print_state(Print &stream);
+
+  public:
+    int classify(unsigned pulse);
+
+    /** The state of the code word received, this is 'volatile' since it is
+     * accessed from both the main loop and the interrupt service routine.
+     */
+    volatile char rx_state = RS_NOSYNC;
+
+    /** Time stamp when the previous interrupt was triggered (when the input pin
+     * transitioned either from 0 to 1 or from 1 to 0.  This is the value of
+     * micros() function.
+     */
+    unsigned long last_timestamp = 0;
+
+    /** The duration of the last pulse width (the time between a transition of the
+     * input pin)
+     */
+    unsigned last_pulse_width = 0;
+
+    /** Number of changes during preamble
+     */
+    char preamble_count = 0;
+
+    /** Number of bits received already.
+     */
+    char rx_bit_count = 0;
+
+    /** Duration of the transmitter clock -- this is determined when the preamble
+     * is received, as the preamble has all the pulse widths the same length.
+     *
+     * The remotes I tested transmit at 2400 bauds, so the tx_clock is always
+     * about 420 micro seconds, however, this code attempts to determine it
+     * dynamically and should adapt to transmitters of different speeds.
+     */
+    unsigned tx_clock = 0;
+
+    /** Number of bits we expect to receive.  The HCS200 data sheet specifies that
+     * 66 bits are transmited.
+     */
+    const unsigned short MAX_BITS = 66;
+
+    /** Buffer where we store the received bits. HCS sends only 66
+     */
+    uint32_t rx_buf[3];
+};