-volatile uint8_t s88_read_count = 0;
-uint8_t s88_read_bit = 0;
-volatile uint8_t s88_read_phase = 0;
-uint8_t s88_data = 0;
-RINGBUFFER(s88_buffer, 8);
-uint8_t s88_out_index = 0;
+static volatile uint8_t s88_read_count = 0;
+static uint8_t s88_read_bit = 0;
+static volatile uint8_t s88_read_phase = 0;
+static uint8_t s88_data = 0;
+static RINGBUFFER(s88_buffer, 8);
+static uint8_t s88_out_index = 0;