X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=firmware%2Fserial.c;fp=firmware%2Fserial.c;h=b7219ae337381b724c0bcd0877185bbf2f8dda69;hb=d8a31ed675778c08ca781beb62863c62d6f0bd94;hp=0000000000000000000000000000000000000000;hpb=af6a469f761ceec44e94bea5fe8e5345fd368966;p=model-railway-devices.git

diff --git a/firmware/serial.c b/firmware/serial.c
new file mode 100644
index 0000000..b7219ae
--- /dev/null
+++ b/firmware/serial.c
@@ -0,0 +1,36 @@
+#include <avr/io.h>
+#include <avr/interrupt.h>
+#include "serial.h"
+
+#define BIT(n) (1<<(n))
+
+static SerialCallback *serial_callback = 0;
+
+void serial_init(uint16_t baud)
+{
+	DDRD = (DDRD&~0x03) | 0x02;
+	PORTD &= ~0x03;
+
+	baud = (F_CPU/16+baud/2)/baud-1;
+	UBRR0H = baud>>8;
+	UBRR0L = baud;
+	UCSR0C = BIT(UCSZ00) | BIT(UCSZ01);  // 8N1
+	UCSR0B = BIT(RXEN0) | BIT(TXEN0);
+}
+
+void serial_set_callback(SerialCallback *cb)
+{
+	serial_callback = cb;
+	UCSR0B |= BIT(RXCIE0);
+}
+
+void serial_write(uint8_t c)
+{
+	while(!(UCSR0A&(1<<UDRE0))) ;
+	UDR0 = c;
+}
+
+ISR(USART_RX_vect)
+{
+	serial_callback(UDR0);
+}