X-Git-Url: https://jxself.org/git/?p=linux-libre-firmware.git;a=blobdiff_plain;f=atusb%2Fuart.c;fp=atusb%2Fuart.c;h=44bec27a4961e182572306ba3591d7b843b0f261;hp=0000000000000000000000000000000000000000;hb=dd4bc9ff49b9a7075e579fdd62fd930d27a9a7df;hpb=c164bf7f87f9081fee7e1a186dd7a87a9a020b9e

diff --git a/atusb/uart.c b/atusb/uart.c
new file mode 100644
index 0000000..44bec27
--- /dev/null
+++ b/atusb/uart.c
@@ -0,0 +1,64 @@
+/*
+ * fw/uart.h - Functions needed for debugging over uart
+ *
+ * Code adapted from http://www.roboternetz.de/wissen/index.php/UART_mit_avr-gcc
+ * and http://www.mikrocontroller.net/articles/AVR-GCC-Tutorial
+ *
+ * Published under the Creative Commons Share-Alike licence
+ * https://creativecommons.org/licenses/by-sa/2.0/de/
+ *
+ * S. Salewski 2007
+ *
+ * Adapted by
+ * Josef Filzmaier 2017
+ */
+
+#include <avr/io.h>
+#include "uart.h"
+
+#define USART_BAUD 38400UL
+#define F_CPU 8000000UL
+
+#define Wait_USART_Ready() while (!(UCSR1A & (1<<UDRE1)))
+#define UART_UBRR (F_CPU/(16L*USART_BAUD)-1)
+
+// initialize USART, 8N1 mode
+void
+uart_init(void)
+{
+/* TODO: Find a working configuration for uart for the atmega32u2 */
+#if CHIP == at90usb1287
+	CLKPR = (1 << CLKPCE);
+	CLKPR = 0; // clock prescaler == 0, so we have 16 MHz mpu frequency
+	UBRR1 = UART_UBRR;
+	UCSR1C = (1 << UCSZ10) | (1 << UCSZ11);
+	UCSR1B = (1 << TXEN1);
+	do
+	{
+		UDR1;
+	}
+	while (UCSR1A & (1 << RXC1));
+#endif
+
+}
+
+int uart_write_char(char c, FILE* stream)
+{
+	if (c == '\n'){
+		uart_new_line();
+	}
+	else {
+		Wait_USART_Ready();
+		UDR1 = c;
+	}
+	return 0;
+}
+
+void
+uart_new_line(void)
+{
+	Wait_USART_Ready();
+	UDR1 = '\r';
+	Wait_USART_Ready();
+	UDR1 = '\n';
+}