Added a printf example that is using irq and a ring buffer to write to USART1 port. It is also reflecting the text you write to the device.

examples/stm32/stm32-h103/usart_irq_printf/usart_irq_printf.ld

@@ -0,0 +1,31 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Linker script for Open-BLDC (STM32F103CBT6, 128K flash, 20K RAM). */
+
+/* Define memory regions. */
+MEMORY
+{
+	rom (rx) : ORIGIN = 0x08000000, LENGTH = 128K
+	ram (rwx) : ORIGIN = 0x20000000, LENGTH = 20K
+}
+
+/* Include the common ld script. */
+INCLUDE libopencm3_stm32.ld
+