Initial commit

src/hal/matrix.h

@@ -0,0 +1,22 @@
+#pragma once
+#include <stdint.h>
+
+// 5×5 button matrix
+// COL_0 × ROW_0–3 = encoder SW buttons
+// COL_1–4 × ROW_0–4 = 20 Cherry MX buttons
+// COL_0 × ROW_4   = not connected
+
+#define MATRIX_COLS  5
+#define MATRIX_ROWS  5
+#define MATRIX_KEYS  25   // col * MATRIX_ROWS + row
+
+// Callback: key index (0–24), pressed = true / released = false
+typedef void (*matrix_cb_t)(uint8_t key, bool pressed);
+
+void matrix_init(matrix_cb_t cb);
+void matrix_scan();
+
+// Helper: key index from logical position
+inline uint8_t matrix_key(uint8_t col, uint8_t row) {
+    return col * MATRIX_ROWS + row;
+}