Add debug serial

include/sta/debug_serial.hpp

@@ -0,0 +1,52 @@
+/**
+ * @brief Debug output via UART.
+ *
+ * Define `STA_DEBUG_SERIAL_ENABLE` in `<sta/config.hpp>` to enable.
+ *
+ * Defining `DEBUG` will automatically enable the module.
+ * Defining `NDEBUG` will always force module to be disabled.
+ *
+ * Application must provide the sta::DebugSerial instance.
+ * NOTE: Include this header before the definition because
+ *       the default internal linkage of const namespace variables
+ *       will cause undefined reference errors otherwise.
+ */
+#ifndef STA_DEBUG_SERIAL_HPP
+#define STA_DEBUG_SERIAL_HPP
+
+#include <sta/config.hpp>
+
+#ifdef DEBUG
+#  ifndef STA_DEBUG_SERIAL_ENABLE
+#    define STA_DEBUG_SERIAL_ENABLE
+#  endif // !STA_DEBUG_SERIAL_ENABLE
+#endif // DEBUG
+
+#ifdef NDEBUG
+#  ifdef STA_DEBUG_SERIAL_ENABLE
+#    undef STA_DEBUG_SERIAL_ENABLE
+#  endif // STA_DEBUG_SERIAL_ENABLE
+#endif // NDEBUG
+
+
+#ifdef STA_DEBUG_SERIAL_ENABLE
+
+#include <sta/uart.hpp>
+
+
+namespace sta
+{
+	extern UART * const DebugSerial;
+} // namespace sta
+
+
+#  define STA_DEBUG_PRINT(...)      sta::DebugSerial->print(__VA_ARGS__)
+#  define STA_DEBUG_PRINTLN(...)    sta::DebugSerial->println(__VA_ARGS__)
+#  define STA_DEBUG_WRITE(b, s)     sta::DebugSerial->write(b, s)
+#else // !STA_DEBUG_SERIAL_ENABLE
+#  define STA_DEBUG_PRINT(...)      ((void)0)
+#  define STA_DEBUG_PRINTLN(...)    ((void)0)
+#  define STA_DEBUG_WRITE(b, s)     ((void)0)
+#endif // !STA_DEBUG_SERIAL_ENABLE
+
+#endif // STA_DEBUG_SERIAL_HPP