From cbb3c9832bbe31d741930d43d3e21a04abeb12f8 Mon Sep 17 00:00:00 2001
From: VG <vg@devys.org>
Date: Wed, 28 Jan 2015 00:03:35 +0100
Subject: first commit

---
 uart.h | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 uart.h

(limited to 'uart.h')

diff --git a/uart.h b/uart.h
new file mode 100644
index 0000000..22e0655
--- /dev/null
+++ b/uart.h
@@ -0,0 +1,76 @@
+/* #define F_CPU 16000000UL <= defined in Makefile */
+#define BAUD 9600
+
+/* This file is *highly* inspired from:
+ * http://www.appelsiini.net/2011/simple-usart-with-avr-libc
+ */
+
+#include <util/setbaud.h>
+
+#if 0
+static inline void uart_init()
+{
+    UCSRB |= (1 << RXEN)  | (1 << TXEN);
+    UCSRC |= (1 << UCSZ0) | (1 << UCSZ1);
+#define BAUD 115200
+#include <util/setbaud.h>
+    UBRRH = UBRRH_VALUE;
+    UBRRL = UBRRL_VALUE;
+#if USE_2X
+    UCSRA |= (1 << U2X);
+#else
+    UCSRA &= ~(1 << U2X);
+#endif
+}
+#endif
+
+void uart_init(void)
+{
+    UBRR0H = UBRRH_VALUE;
+    UBRR0L = UBRRL_VALUE;
+
+#if USE_2X
+    UCSR0A |= _BV(U2X0);
+#else
+    UCSR0A &= ~(_BV(U2X0));
+#endif
+
+    UCSR0C = _BV(UCSZ01) | _BV(UCSZ00); /* 8-bit data */
+    UCSR0B = _BV(RXEN0) | _BV(TXEN0);   /* Enable RX and TX */
+}
+
+void uart_putchar(char c)
+{
+    UDR0 = c;
+    loop_until_bit_is_set(UCSR0A, TXC0); /* Wait until transmission ready. */
+}
+
+char uart_getchar(void)
+{
+    loop_until_bit_is_set(UCSR0A, RXC0); /* Wait until data exists. */
+    return UDR0;
+}
+
+#if 0
+/* alternatives for stream uses */
+void uart_putchar(char c, FILE *stream)
+{
+    if (c == '\n') {
+        uart_putchar('\r', stream);
+    }
+    loop_until_bit_is_set(UCSR0A, UDRE0);
+    UDR0 = c;
+}
+
+char uart_getchar(FILE *stream)
+{
+    loop_until_bit_is_set(UCSR0A, RXC0); /* Wait until data exists. */
+    return UDR0;
+}
+#endif
+
+#if 0
+FILE uart_output = FDEV_SETUP_STREAM(uart_putchar, NULL, _FDEV_SETUP_WRITE);
+FILE uart_input = FDEV_SETUP_STREAM(NULL, uart_getchar, _FDEV_SETUP_READ);
+FILE uart_io FDEV_SETUP_STREAM(uart_putchar, uart_getchar, _FDEV_SETUP_RW);
+#endif
-- 
cgit v1.2.3