Add firmware for the ATUSB IEEE 802.15.4 USB Adapter

[linux-libre-firmware.git] / atusb / uart.c

diff --git a/atusb/uart.c b/atusb/uart.c
new file mode 100644 (file)
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';
+}