1 files changed, 32 insertions, 0 deletions
diff --git a/door_lock/serial.c b/door_lock/serial.c
new file mode 100644
index 0000000..4dba0e5
--- /dev/null
+++ b/door_lock/serial.c
@@ -0,0 +1,32 @@
+#include <avr/io.h>
+#include <util/setbaud.h>
+
+#include "serial.h"
+
+void serial_init(void)
+{
+	UBRR0H = UBRRH_VALUE;
+	UBRR0L = UBRRL_VALUE;
+#if USE_2X
+	UCSR0A |= (1 << U2X0);
+#else
+	UCSR0A &= ~(1 << U2X0);
+#endif
+	UCSR0B = (1 << TXEN0) | (1 << RXEN0);
+	UCSR0C = (1 << UCSZ01) | (1 << UCSZ00);
+}
+
+static void serial_write_raw(unsigned char data)
+{
+	while (!(UCSR0A & (1 << UDRE0)))
+		;
+	UDR0 = data;
+}
+
+void serial_write(const char *s)
+{
+	for (; *s; s++)
+		serial_write_raw(*s);
+	serial_write_raw('\r');
+	serial_write_raw('\n');
+}