tq: rewrite for shift register semanticsHEADmaster

1 files changed, 49 insertions, 0 deletions

diff --git a/ThrottleQuadrant.hpp b/ThrottleQuadrant.hpp
new file mode 100644
index 0000000..8776aab
--- /dev/null
+++ b/ThrottleQuadrant.hpp
@@ -0,0 +1,49 @@
+#ifndef SAITEK_THROTTLE_QUADRANT_HPP
+#define SAITEK_THROTTLE_QUADRANT_HPP
+
+#include <limits.h>
+#include <stddef.h>
+#include <stdint.h>
+
+struct SaitekThrottleQuadrant {
+
+  //! The data read from the throttle quadrant.
+  struct [[gnu::packed]] Data {
+    uint8_t left;
+    uint8_t right;
+    uint8_t middle;
+    uint16_t buttons : 9;
+    uint16_t : 0;
+  };
+
+  //! The minimum delay between successive read operations.
+  auto constexpr static readDelayMillis = 25u;
+
+  //! Initialize the throttle quadrant interface.
+  auto begin(unsigned clock_pin, unsigned latch_pin, unsigned data_pin) noexcept -> void;
+
+  //! Read the current state of the throttle quadrant.
+  auto read() noexcept -> Data;
+
+private:
+  //! The time for the clock to propagate.
+  auto constexpr static clockDelayMicros = 25u;
+
+  //! The time for the latch to settle.
+  auto constexpr static latchDelayMicros = 5u;
+
+  //! The number of buttons on the throttle quadrant.
+  auto constexpr static numberOfButtons = 9u;
+
+  auto beginTransaction() -> void;
+  auto endTransaction() -> void;
+
+  template<typename T, size_t Bits = sizeof(T) * CHAR_BIT>
+  auto doRead() -> T;
+
+  unsigned clock_pin{};
+  unsigned latch_pin{};
+  unsigned data_pin{};
+} static ThrottleQuadrant;
+
+#endif
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