+/**
+ * Define the macros needed to set the serial input bit of SIPO device
+ * low or high.
+ */
+#define SIPO_SI_HIGH()/* Implement me! */
+#define SIPO_SI_LOW() /* Implement me! */
+
+/**
+ * Drive pin to load the bit, presented in serial-in pin,
+ * into sipo shift register.
+ */
+#define SIPO_SI_CLOCK() /* Implement me! */
+
+/**
+ * Clock the content of shift register to output.
+ */
+#define SIPO_LOAD() /* Implement me! */
+
+/**
+ * Enable the shift register output.
+ */
+#define SIPO_ENABLE() /* Implement me! */