initial commit

23 files changed, 1702 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..da2d32f
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,5 @@
+app/*.o
+app/*.d
+app/*.elf
+app/*.map
+app/*~
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..29e93ae
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "libopencm3"]
+	path = libopencm3
+	url = git://github.com/libopencm3/libopencm3.git
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..7b28523
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,11 @@
+default:app.dummy
+
+app.dummy:
+	make -C app
+
+libopencm3.dummy:
+	make -C libopencm3
+
+clean:
+	make -C app $@
+	make -C libopencm3 $@
diff --git a/Makefile.include b/Makefile.include
new file mode 100644
index 0000000..3eccc25
--- /dev/null
+++ b/Makefile.include
@@ -0,0 +1,48 @@
+##
+## This file is part of the libopencm3 project.
+##
+## Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+## Copyright (C) 2010 Piotr Esden-Tempski <piotr@esden.net>
+##
+## This library is free software: you can redistribute it and/or modify
+## it under the terms of the GNU Lesser General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This library 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 Lesser General Public License for more details.
+##
+## You should have received a copy of the GNU Lesser General Public License
+## along with this library.  If not, see <http://www.gnu.org/licenses/>.
+##
+
+LIBNAME		= opencm3_stm32f1
+DEFS		= -DSTM32F1
+
+FP_FLAGS	?= -msoft-float
+ARCH_FLAGS	= -mthumb -mcpu=cortex-m3 $(FP_FLAGS) -mfix-cortex-m3-ldrd
+
+################################################################################
+# OpenOCD specific variables
+
+#OOCD		?= openocd
+#OOCD_INTERFACE	?= flossjtag
+#OOCD_BOARD	?= olimex_stm32_h103
+
+OOCD            ?= openocd
+OOCD_INTERFACE  ?= ../interface/j-link.cfg
+OOCD_BOARD      ?= ../board/STM32F103R_BOARD.cfg
+
+################################################################################
+# Black Magic Probe specific variables
+# Set the BMP_PORT to a serial port and then BMP is used for flashing
+BMP_PORT	?=
+
+################################################################################
+# texane/stlink specific variables
+#STLINK_PORT	?= :4242
+
+
+include ../Makefile.rules
diff --git a/Makefile.rules b/Makefile.rules
new file mode 100644
index 0000000..0e521e6
--- /dev/null
+++ b/Makefile.rules
@@ -0,0 +1,252 @@
+#
+## This file is part of the libopencm3 project.
+##
+## Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+## Copyright (C) 2010 Piotr Esden-Tempski <piotr@esden.net>
+## Copyright (C) 2013 Frantisek Burian <BuFran@seznam.cz>
+##
+## This library is free software: you can redistribute it and/or modify
+## it under the terms of the GNU Lesser General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This library is distributed in the hope that it will be useful,
+## but WITHOUT ANY WARRANTY; without even the implied warranty of
+## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+## GNU Lesser General Public License for more details.
+##
+## You should have received a copy of the GNU Lesser General Public License
+## along with this library.  If not, see <http://www.gnu.org/licenses/>.
+##
+
+# Be silent per default, but 'make V=1' will show all compiler calls.
+ifneq ($(V),1)
+Q		:= @
+NULL		:= 2>/dev/null
+endif
+
+###############################################################################
+# Executables
+
+PREFIX		?= arm-none-eabi
+
+CC		:= $(PREFIX)-gcc
+CXX		:= $(PREFIX)-g++
+LD		:= $(PREFIX)-gcc
+AR		:= $(PREFIX)-ar
+AS		:= $(PREFIX)-as
+OBJCOPY		:= $(PREFIX)-objcopy
+OBJDUMP		:= $(PREFIX)-objdump
+GDB		:= $(PREFIX)-gdb
+STFLASH		= $(shell which st-flash)
+STYLECHECK	:= /checkpatch.pl
+STYLECHECKFLAGS	:= --no-tree -f --terse --mailback
+STYLECHECKFILES	:= $(shell find . -name '*.[ch]')
+
+
+###############################################################################
+# Source files
+
+LDSCRIPT	?= $(BINARY).ld
+
+#OBJS		+= $(BINARY).o
+
+
+ifeq ($(strip $(OPENCM3_DIR)),)
+# user has not specified the library path, so we try to detect it
+
+# where we search for the library
+LIBPATHS := ./libopencm3 ../libopencm3 
+
+OPENCM3_DIR := $(wildcard $(LIBPATHS:=/locm3.sublime-project))
+OPENCM3_DIR := $(firstword $(dir $(OPENCM3_DIR)))
+
+ifeq ($(strip $(OPENCM3_DIR)),)
+$(warning Cannot find libopencm3 library in the standard search paths.)
+$(error Please specify it through OPENCM3_DIR variable!)
+endif
+endif
+
+ifeq ($(V),1)
+$(info Using $(OPENCM3_DIR) path to library)
+endif
+
+INCLUDE_DIR	= $(OPENCM3_DIR)/include
+LIB_DIR		= $(OPENCM3_DIR)/lib
+SCRIPT_DIR	= $(OPENCM3_DIR)/scripts
+
+###############################################################################
+# C flags
+
+#CFLAGS		+= -Os -g
+CFLAGS		+= -g
+CFLAGS		+= -Wextra -Wimplicit-function-declaration
+CFLAGS		+= -Wmissing-prototypes -Wstrict-prototypes
+CFLAGS		+= -fno-common -ffunction-sections -fdata-sections
+
+###############################################################################
+# C++ flags
+
+CXXFLAGS	+= -Os -g
+CXXFLAGS	+= -Wextra -Wshadow -Wredundant-decls  -Weffc++
+CXXFLAGS	+= -fno-common -ffunction-sections -fdata-sections
+
+###############################################################################
+# C & C++ preprocessor common flags
+
+CPPFLAGS	+= -MD
+CPPFLAGS	+= -Wall -Wundef
+
+INCLUDES	= -I$(INCLUDE_DIR) 
+DEFINES		= $(DEFS)
+
+CPPFLAGS 	+= $(INCLUDES) $(DEFINES)
+
+###############################################################################
+# Linker flags
+
+LDFLAGS		+= --static -nostartfiles
+LDFLAGS		+= -L$(LIB_DIR)
+LDFLAGS		+= -T$(LDSCRIPT)
+LDFLAGS		+= -Wl,-Map=$(*).map
+LDFLAGS		+= -Wl,--gc-sections
+ifeq ($(V),99)
+LDFLAGS		+= -Wl,--print-gc-sections
+endif
+
+###############################################################################
+# Used libraries
+
+LDLIBS		+= -l$(LIBNAME)
+LDLIBS		+= -Wl,--start-group -lc -lnosys -lgcc -Wl,--end-group
+
+###############################################################################
+###############################################################################
+###############################################################################
+
+.SUFFIXES: .elf .bin .hex .srec .list .map .images .dfu
+.SECONDEXPANSION:
+.SECONDARY:
+
+all: elf
+
+elf: $(BINARY).elf
+bin: $(BINARY).bin
+hex: $(BINARY).hex
+srec: $(BINARY).srec
+list: $(BINARY).list
+
+images: $(BINARY).images
+flash: $(BINARY).flash
+
+%.images: %.bin %.hex %.srec %.list %.map %.dfu
+	@#printf "*** $* images generated ***\n"
+
+%.bin: %.elf
+	@#printf "  OBJCOPY $(*).bin\n"
+	$(Q)$(OBJCOPY) -Obinary $(*).elf $(*).bin
+
+%.hex: %.elf
+	@#printf "  OBJCOPY $(*).hex\n"
+	$(Q)$(OBJCOPY) -Oihex $(*).elf $(*).hex
+
+%.dfu: %.elf
+	@#printf "  OBJCOPY $(*).dfu\n"
+	$(Q)$(OBJCOPY) -Obinary $(*).elf $(*).dfu
+
+%.srec: %.elf
+	@#printf "  OBJCOPY $(*).srec\n"
+	$(Q)$(OBJCOPY) -Osrec $(*).elf $(*).srec
+
+%.list: %.elf
+	@#printf "  OBJDUMP $(*).list\n"
+	$(Q)$(OBJDUMP) -S $(*).elf > $(*).list
+
+fish:
+	echo %.elf %.map: $(OBJS) $(LDSCRIPT) $(LIB_DIR)/lib$(LIBNAME).a
+	echo $(BINARY).elf
+
+%.elf %.map: $(OBJS) $(LDSCRIPT) $(LIB_DIR)/lib$(LIBNAME).a
+	@#printf "  LD      $(*).elf\n"
+	$(Q)$(LD) $(LDFLAGS) $(ARCH_FLAGS) $(OBJS) $(LDLIBS) -o $(*).elf
+
+%.o: %.c
+	@#printf "  CC      $(*).c\n"
+	$(Q)$(CC) $(CFLAGS) $(CPPFLAGS) $(ARCH_FLAGS) -o $(*).o -c $(*).c
+
+%.o: %.cxx
+	@#printf "  CXX     $(*).cxx\n"
+	$(Q)$(CXX) $(CXXFLAGS) $(CPPFLAGS) $(ARCH_FLAGS) -o $(*).o -c $(*).cxx
+
+%.o: %.cpp
+	@#printf "  CXX     $(*).cpp\n"
+	$(Q)$(CXX) $(CXXFLAGS) $(CPPFLAGS) $(ARCH_FLAGS) -o $(*).o -c $(*).cpp
+
+clean:
+	@#printf "  CLEAN\n"
+	$(Q)$(RM) *.o *.d *.elf *.bin *.hex *.srec *.list *.map *~ *.dfu ${EXTRA_CLEAN}
+
+stylecheck: $(STYLECHECKFILES:=.stylecheck)
+styleclean: $(STYLECHECKFILES:=.styleclean)
+
+# the cat is due to multithreaded nature - we like to have consistent chunks of text on the output
+%.stylecheck: %
+	$(Q)$(SCRIPT_DIR)$(STYLECHECK) $(STYLECHECKFLAGS) $* > $*.stylecheck; \
+		if [ -s $*.stylecheck ]; then \
+			cat $*.stylecheck; \
+		else \
+			rm -f $*.stylecheck; \
+		fi;
+
+%.styleclean:
+	$(Q)rm -f $*.stylecheck;
+
+
+%.stlink-flash: %.bin
+	@printf "  FLASH  $<\n"
+	$(Q)$(STFLASH) write $(*).bin 0x8000000
+
+ifeq ($(STLINK_PORT),)
+ifeq ($(BMP_PORT),)
+ifeq ($(OOCD_SERIAL),)
+%.flash: %.hex
+	@printf "  FLASH   $<\n"
+	@# IMPORTANT: Don't use "resume", only "reset" will work correctly!
+	$(Q)$(OOCD) -f $(OOCD_INTERFACE) \
+		    -f $(OOCD_BOARD) \
+		    -c "init" -c "reset init" \
+		    -c "flash write_image erase $(*).hex" \
+		    -c "reset" \
+		    -c "shutdown" $(NULL)
+else
+%.flash: %.hex
+	@printf "  FLASH   $<\n"
+	@# IMPORTANT: Don't use "resume", only "reset" will work correctly!
+	$(Q)$(OOCD) -f $(OOCD_INTERFACE) \
+		    -f $(OOCD_BOARD) \
+		    -c "ft2232_serial $(OOCD_SERIAL)" \
+		    -c "init" -c "reset init" \
+		    -c "flash write_image erase $(*).hex" \
+		    -c "reset" \
+		    -c "shutdown" $(NULL)
+endif
+else
+%.flash: %.elf
+	@printf "  GDB   $(*).elf (flash)\n"
+	$(Q)$(GDB) --batch \
+		   -ex 'target extended-remote $(BMP_PORT)' \
+		   -x $(SCRIPT_DIR)/black_magic_probe_flash.scr \
+		   $(*).elf
+endif
+else
+%.flash: %.elf
+	@printf "  GDB   $(*).elf (flash)\n"
+	$(Q)$(GDB) --batch \
+		   -ex 'target extended-remote $(STLINK_PORT)' \
+		   -x $(SCRIPT_DIR)/stlink_flash.scr \
+		   $(*).elf
+endif
+
+.PHONY: images clean stylecheck styleclean elf bin hex srec list
+
+-include $(OBJS:.o=.d)
diff --git a/app/Makefile b/app/Makefile
new file mode 100644
index 0000000..0ed735d
--- /dev/null
+++ b/app/Makefile
@@ -0,0 +1,61 @@
+##
+## This file is part of the libopencm3 project.
+##
+## Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+##
+## This library is free software: you can redistribute it and/or modify
+## it under the terms of the GNU Lesser General Public License as published by
+## the Free Software Foundation, either version 3 of the License, or
+## (at your option) any later version.
+##
+## This library 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 Lesser General Public License for more details.
+##
+## You should have received a copy of the GNU Lesser General Public License
+## along with this library.  If not, see <http://www.gnu.org/licenses/>.
+##
+
+CPROTO=cproto
+PROG=app
+
+V=1
+default: ${PROG}.elf
+
+CSRCS=i2c.c lcd.c led.c main.c ring.c ticker.c usart.c
+
+
+BINARY = ${PROG}
+OBJS = ${CSRCS:%.c=%.o}  
+
+include ../Makefile.include
+
+DID=$(shell printf '\#include "id.h"\nID_PRODUCT' | ${CC} -I.. -E - | grep -v ^\# )
+
+INCLUDES +=  -I..
+
+#dfu:${PROG}.dfu
+#	dfu-util -R -a 0 -d 1d6b:${DID} -s 0x08002000:leave -D $<
+
+program: ${PROG}.hex
+	echo init | nc -t localhost 4444
+	echo reset init | nc -t localhost 4444
+	echo flash write_image erase ${PWD}/$< | nc -t localhost 4444
+	echo reset run | nc -t localhost 4444
+
+ds:
+	$(Q)$(OOCD) -f $(OOCD_INTERFACE) \
+                    -f $(OOCD_BOARD) 
+
+debug: ${PROG}.elf
+	${PREFIX}-gdb -x gdb.script ${PROG}.elf 
+
+#	openocd
+
+protos: ${CSRCS}
+	echo -n > prototypes.h
+	${CPROTO} $(INCLUDES) $(DEFINES) -e -v ${CSRCS} > prototypes.h.tmp
+	mv -f prototypes.h.tmp prototypes.h
+
+
diff --git a/app/app.ld b/app/app.ld
new file mode 100644
index 0000000..0fb2378
--- /dev/null
+++ b/app/app.ld
@@ -0,0 +1,38 @@
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library 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 Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/* Linker script for Olimex STM32-H103 (STM32F103RBT6, 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_stm32f1.ld
+
+
+
+
+/* PROVIDE(_stack = dfu_shared_location ); */
+
+
+
diff --git a/app/gdb.script b/app/gdb.script
new file mode 100644
index 0000000..7cf9d09
--- /dev/null
+++ b/app/gdb.script
@@ -0,0 +1,2 @@
+target remote localhost:3333
+cont
diff --git a/app/i2c.c b/app/i2c.c
new file mode 100644
index 0000000..74aed9d
--- /dev/null
+++ b/app/i2c.c
@@ -0,0 +1,281 @@
+#include "project.h"
+
+
+#define I2C I2C1
+
+#define SCL 	GPIO6
+#define SDA	GPIO7
+
+void
+i2c_clear_start (uint32_t i2c)
+{
+  I2C_CR1 (i2c) &= ~(uint32_t) I2C_CR1_START;
+}
+
+#if 0
+static void
+i2cp_ds (void)
+{
+  uint32_t i2c = I2C;
+  printf ("CR1=%08x CR2=%08x\r\n", (unsigned) I2C_CR1 (i2c),
+          (unsigned) I2C_CR2 (i2c));
+  printf ("SR1=%08x SR2=%08x\r\n", (unsigned) I2C_SR1 (i2c),
+          (unsigned) I2C_SR2 (i2c));
+
+
+  usart1_drain ();
+}
+#endif
+
+
+
+void
+i2cp_start (void)
+{
+  i2c_send_start (I2C);
+  while (!((I2C_SR1 (I2C) & I2C_SR1_SB)
+           & (I2C_SR2 (I2C) & (I2C_SR2_MSL | I2C_SR2_BUSY))));
+}
+
+void
+i2cp_abort_start (void)
+{
+  i2c_clear_start (I2C);
+  delay_us (10);
+}
+
+void
+i2cp_stop (void)
+{
+  i2c_send_stop (I2C);
+}
+
+
+void
+i2cp_abort_stop (void)
+{
+  i2c_clear_stop (I2C);
+  delay_us (10);
+}
+
+int
+i2cp_send_data (uint8_t v)
+{
+  uint32_t reg;
+
+  i2c_send_data (I2C, v);
+
+  while (!
+         ((reg =
+           I2C_SR1 (I2C)) & (I2C_SR1_BTF | I2C_SR1_BERR | I2C_SR1_ARLO |
+                             I2C_SR1_AF | I2C_SR1_PECERR | I2C_SR1_TIMEOUT |
+                             I2C_SR1_SMBALERT)));
+  I2C_SR1 (I2C) =
+    reg & ~(I2C_SR1_BERR | I2C_SR1_ARLO | I2C_SR1_AF | I2C_SR1_PECERR |
+            I2C_SR1_TIMEOUT | I2C_SR1_SMBALERT);
+
+
+  return (reg & I2C_SR1_BTF) ? 0 : -1;
+}
+
+/*0 on success 1 on failure*/
+int
+i2cp_start_transaction (uint8_t a, int wnr)
+{
+  uint32_t reg;
+  uint32_t __attribute__ ((unused)) dummy;
+
+  i2c_send_start (I2C);
+  while (!((I2C_SR1 (I2C) & I2C_SR1_SB)
+           & (I2C_SR2 (I2C) & (I2C_SR2_MSL | I2C_SR2_BUSY))));
+
+  i2c_send_7bit_address (I2C, a, wnr);
+
+  while (!
+         ((reg =
+           I2C_SR1 (I2C)) & (I2C_SR1_ADDR | I2C_SR1_BERR | I2C_SR1_ARLO |
+                             I2C_SR1_AF | I2C_SR1_PECERR | I2C_SR1_TIMEOUT |
+                             I2C_SR1_SMBALERT)));
+  dummy = I2C_SR2 (I2C);
+
+  I2C_SR1 (I2C) =
+    reg & ~(I2C_SR1_BERR | I2C_SR1_ARLO | I2C_SR1_AF | I2C_SR1_PECERR |
+            I2C_SR1_TIMEOUT | I2C_SR1_SMBALERT);
+
+
+  return (reg == 0x82) ? 0 : -1;
+}
+
+
+static int mutex = 0;
+
+int
+i2cp_lock (void)
+{
+  if (__sync_add_and_fetch (&mutex, 1) != 1)
+    {
+      __sync_sub_and_fetch (&mutex, 1);
+      return -1;
+    }
+
+  return 0;
+}
+
+
+void
+i2cp_unlock (void)
+{
+  __sync_sub_and_fetch (&mutex, 1);
+}
+
+ /*This is stupid, it bit bangs a dummy transaction to get the host i2c controller back in the game */
+static void
+i2cp_reset_sm (void)
+{
+  int i;
+
+  gpio_set_mode (GPIOB, GPIO_MODE_OUTPUT_50_MHZ,
+                 GPIO_CNF_OUTPUT_PUSHPULL, GPIO_I2C1_SCL | GPIO_I2C1_SDA);
+
+  gpio_set (GPIOB, GPIO_I2C1_SDA);
+  gpio_set (GPIOB, GPIO_I2C1_SCL);
+  delay_us (10);
+  gpio_clear (GPIOB, GPIO_I2C1_SDA);
+  delay_us (10);
+  gpio_clear (GPIOB, GPIO_I2C1_SCL);
+
+  for (i = 0; i < 9; ++i)
+    {
+      delay_us (10);
+      gpio_set (GPIOB, GPIO_I2C1_SCL);
+      delay_us (10);
+      gpio_clear (GPIOB, GPIO_I2C1_SCL);
+      delay_us (10);
+    }
+  gpio_set (GPIOB, GPIO_I2C1_SCL);
+  delay_us (10);
+  gpio_set (GPIOB, GPIO_I2C1_SDA);
+  delay_us (10);
+
+}
+
+void
+i2cp_start_dma (uint8_t * buf, int len)
+{
+  dma_channel_reset (DMA1, DMA_CHANNEL6);
+  dma_set_peripheral_address (DMA1, DMA_CHANNEL6, (uint32_t) & I2C1_DR);
+  dma_set_memory_address (DMA1, DMA_CHANNEL6, (uint32_t) buf);
+  dma_set_number_of_data (DMA1, DMA_CHANNEL6, len);
+  dma_set_read_from_memory (DMA1, DMA_CHANNEL6);
+  dma_enable_memory_increment_mode (DMA1, DMA_CHANNEL6);
+  dma_set_peripheral_size (DMA1, DMA_CHANNEL6, DMA_CCR_PSIZE_8BIT);
+  dma_set_memory_size (DMA1, DMA_CHANNEL6, DMA_CCR_MSIZE_8BIT);
+  dma_set_priority (DMA1, DMA_CHANNEL6, DMA_CCR_PL_MEDIUM);
+  dma_enable_transfer_complete_interrupt (DMA1, DMA_CHANNEL6);
+  dma_enable_transfer_error_interrupt (DMA1, DMA_CHANNEL6);
+  dma_enable_channel (DMA1, DMA_CHANNEL6);
+
+  i2c_enable_dma (I2C1);
+
+}
+
+int
+i2cp_dma_in_progress (void)
+{
+  return !(DMA1_ISR & (DMA_ISR_TCIF6 | DMA_ISR_TEIF6));
+}
+
+void
+i2cp_stop_dma (void)
+{
+  DMA1_IFCR |= DMA_IFCR_CTCIF7 | DMA_IFCR_CTEIF6 | DMA_IFCR_CGIF6;
+
+  dma_disable_transfer_complete_interrupt (DMA1, DMA_CHANNEL6);
+  dma_disable_transfer_error_interrupt (DMA1, DMA_CHANNEL6);
+
+  i2c_disable_dma (I2C1);
+  dma_disable_channel (DMA1, DMA_CHANNEL7);
+}
+
+void
+i2cp_reset (void)
+{
+  while (i2cp_lock ());
+  i2cp_start ();
+  i2cp_abort_start ();
+  i2cp_stop ();
+  i2cp_abort_stop ();
+
+  i2cp_start ();
+  i2cp_abort_start ();
+  i2cp_stop ();
+  i2cp_abort_stop ();
+  i2cp_unlock ();
+}
+
+
+
+void
+i2cp_scan (void)
+{
+  int i, r;
+
+  return;
+  i2cp_reset ();
+
+  printf ("Probing bus\r\n");
+  for (i = 0; i < 128; ++i)
+    {
+      while (i2cp_lock ());
+      i2cp_start ();
+      i2cp_abort_start ();
+      i2cp_stop ();
+      i2cp_abort_stop ();
+      r = i2cp_start_transaction (i, I2C_WRITE);
+      i2cp_stop ();
+      i2cp_unlock ();
+      if (!r)
+        printf ("Found device at address 0x%x\r\n", i);
+      usart1_drain ();
+    }
+  printf ("Done\r\n");
+  i2cp_reset ();
+
+}
+
+void
+i2cp_init (void)
+{
+  rcc_periph_clock_enable (RCC_I2C1);
+  rcc_periph_clock_enable (RCC_DMA1);
+
+  while (i2cp_lock ());
+
+
+  i2c_peripheral_enable (I2C);
+  i2c_clear_start (I2C);
+  i2c_clear_stop (I2C);
+  i2c_reset (I2C);
+  i2c_peripheral_enable (I2C);
+
+  I2C_CR1 (I2C) |= I2C_CR1_SWRST;
+  delay_us (1000);
+  I2C_CR1 (I2C) &= ~I2C_CR1_SWRST;
+
+
+  i2cp_reset_sm ();
+
+  gpio_set_mode (GPIOB, GPIO_MODE_OUTPUT_50_MHZ,
+                 GPIO_CNF_OUTPUT_ALTFN_OPENDRAIN,
+                 GPIO_I2C1_SCL | GPIO_I2C1_SDA);
+
+  i2c_set_clock_frequency (I2C, I2C_CR2_FREQ_36MHZ);
+  i2c_set_standard_mode (I2C);
+  i2c_set_ccr (I2C, 0x200);     /* t_high=t_high=CCR * Tpclk1 */
+  i2c_set_trise (I2C, 0x0b);
+
+  i2c_set_own_7bit_slave_address (I2C, 0x00);
+
+  i2c_peripheral_enable (I2C);
+  i2cp_unlock ();
+}
diff --git a/app/i2c.h b/app/i2c.h
new file mode 100644
index 0000000..26570d5
--- /dev/null
+++ b/app/i2c.h
@@ -0,0 +1,2 @@
+#define I2C_WRITE 0
+#define I2C_READ 1
diff --git a/app/lcd.c b/app/lcd.c
new file mode 100644
index 0000000..e4a91ab
--- /dev/null
+++ b/app/lcd.c
@@ -0,0 +1,478 @@
+#include "project.h"
+
+#define FOO do { printf("lcd:%x\r\n",__LINE__); usart1_drain(); } while (0)
+
+#define PCF8574_I2C_ADDRESS 0x27
+
+#define LINE_RS		0x1
+#define LINE_RnW	0x2
+#define LINE_EN		0x4
+#define LINE_BACKLIGHT	0x8
+
+#define LCD_CLEAR	0x1
+#define LCD_HOME	0x2
+
+#define LCD_DISP 	0x8
+#define LCD_DISP_ON 	0x4
+#define LCD_DISP_CURSOR 0x2
+#define LCD_DISP_CURSOR_BLINK 0x1
+
+#define LCD_FUNC        0x20
+#define LCD_FUNC_8BIT   0x10
+#define LCD_FUNC_4BIT	0x00
+#define LCD_FUNC_2ROWS	0x08
+#define LCD_FUNC_1ROW 	0x00
+#define LCD_FUNC_5x10 	0x04
+#define LCD_FUNC_5X7	0x00
+
+#define LCD_SET_DDRAM_ADDR 0x80
+
+#define LCD_H_SHIFT 5
+#define LCD_RS (1 << LCD_H_SHIFT)
+#define LCD_W 20
+#define LCD_W_MASK (LCD_RS -1 )
+#define LCD_H 4
+#define LCD_SZ (LCD_H << LCD_H_SHIFT)
+#define LCD_POS(c,r) (((r) << LCD_H_SHIFT ) +(c))
+
+#define BYTES_PER_BYTE 6
+
+#define DMA_BUF_SZ (BYTES_PER_BYTE * ( (1 + LCD_W) *LCD_H  + 1))
+
+static uint8_t dma_buf[DMA_BUF_SZ];
+static uint8_t update_buf[DMA_BUF_SZ];
+static int dma_in_progress = 0;
+static int refresh_enabled = 0;
+
+static int backlight;
+static int pos;
+
+static void
+clock_nibble (uint8_t n)
+{
+  if (backlight)
+    n |= LINE_BACKLIGHT;
+  i2cp_send_data (n);
+  i2cp_send_data (LINE_EN | n);
+  i2cp_send_data (n);
+}
+
+
+static void
+write_reg (uint8_t c, int r)
+{
+  uint8_t b;
+
+  b = c & 0xf0;
+  if (r)
+    b |= LINE_RS;
+
+  clock_nibble (b);
+
+  b = (c & 0xf) << 4;
+  if (r)
+    b |= LINE_RS;
+
+  clock_nibble (b);
+}
+
+static void
+send_command (uint8_t c)
+{
+  write_reg (c, 0);
+}
+
+static void
+send_one_command (uint8_t cmd, int delay)
+{
+  while (i2cp_lock ());
+  i2cp_start_transaction (PCF8574_I2C_ADDRESS, I2C_WRITE);
+  send_command (cmd);
+  i2cp_stop ();
+  if (delay)
+    delay_ms (delay);
+  i2cp_unlock ();
+}
+
+
+
+static void
+cls (void)
+{
+  send_one_command (LCD_CLEAR, 2);
+}
+
+#if 0
+static void
+home (void)
+{
+  send_one_command (LCD_HOME, 2);
+}
+#endif
+
+static void
+on (void)
+{
+  send_one_command (LCD_DISP | LCD_DISP_ON /* | LCD_DISP_CURSOR */ , 4);
+}
+
+static void
+off (void)
+{
+  send_one_command (LCD_DISP, 4);
+}
+
+static int
+lcd_addr (int x, int y)
+{
+  return x + ((y & 1) << 6) + ((y & 2) ? 20 : 0);
+}
+
+
+#if 0
+static void
+move (uint8_t c, uint8_t r)
+{
+  send_one_command (LCD_SET_DDRAM_ADDR | lcd_addr (c, r), 2);
+}
+#endif
+
+
+uint32_t refresh_wdt = 0;
+
+static void
+start_dma (void)
+{
+  if (dma_in_progress)
+    return;
+
+  refresh_wdt = 0;
+
+  dma_in_progress = 1;
+
+  memcpy (dma_buf, update_buf, DMA_BUF_SZ);
+  i2cp_start_transaction (PCF8574_I2C_ADDRESS, I2C_WRITE);
+  i2cp_start_dma (dma_buf, DMA_BUF_SZ);
+
+}
+
+void
+dma1_channel6_isr (void)
+{
+  if (dma_in_progress)
+    {
+      i2cp_stop_dma ();
+
+      i2cp_stop ();
+      dma_in_progress = 0;
+    }
+
+  if (refresh_enabled)
+    start_dma ();
+}
+
+void
+lcd_refresh_wdt (void)
+{
+  refresh_wdt++;
+
+  if (refresh_wdt < 1000)
+    return;
+
+  refresh_wdt = 0;
+
+/*No refresh for 1s, restart everything */
+
+  i2cp_stop_dma ();
+  i2cp_stop ();
+  dma_in_progress = 0;
+
+  start_dma ();
+
+}
+
+static inline void
+dma_clock_nibble (uint8_t * ptr, uint8_t n)
+{
+  if (backlight)
+    n |= LINE_BACKLIGHT;
+  *(ptr++) = n;
+  *(ptr++) = n | LINE_EN;
+  *(ptr++) = n;
+}
+
+
+static inline int
+dma_write_reg (uint8_t * ptr, uint8_t c, int r)
+{
+  uint8_t b;
+
+  b = c & 0xf0;
+  if (r)
+    b |= LINE_RS;
+
+  dma_clock_nibble (ptr, b);
+  ptr += 3;
+
+  b = (c & 0xf) << 4;
+  if (r)
+    b |= LINE_RS;
+
+  dma_clock_nibble (ptr, b);
+
+  return 6;
+}
+
+static inline int
+dma_command (uint8_t * ptr, uint8_t c)
+{
+  return dma_write_reg (ptr, c, 0);
+}
+
+static inline int
+dma_data (uint8_t * ptr, uint8_t c)
+{
+  return dma_write_reg (ptr, c, 1);
+}
+
+
+static void
+dma_generate_stream (void)
+{
+  uint8_t *dma_ptr;
+  int x, y, i;
+
+  dma_ptr = update_buf;
+/* 6 bytes per character, 6 bytes to move position, 5 moves + 20*4 chars => 510*/
+
+  for (y = 0; y < LCD_H; ++y)
+    {
+
+      dma_ptr += dma_command (dma_ptr, LCD_SET_DDRAM_ADDR | lcd_addr (0, y));
+
+      i = y << LCD_H_SHIFT;
+
+      for (x = 0; x < LCD_W; ++x, i++)
+        {
+          dma_ptr += dma_data (dma_ptr, ' ');
+        }
+    }
+
+  dma_ptr += dma_command (dma_ptr, LCD_SET_DDRAM_ADDR |
+                          lcd_addr (pos & LCD_W_MASK, pos >> LCD_H_SHIFT));
+
+}
+
+
+static void
+dma_change_backlight (void)
+{
+  int len = DMA_BUF_SZ;
+  uint8_t *p = update_buf;
+
+  cm_disable_interrupts ();
+
+  if (backlight)
+    while (p++, len--)
+      *p |= LINE_BACKLIGHT;
+  else
+    while (p++, len--)
+      *p &= ~LINE_BACKLIGHT;
+
+  cm_enable_interrupts ();
+}
+
+
+static int
+dma_offset (int x, int y)
+{
+  return BYTES_PER_BYTE * (1 + x + y * (LCD_W + 1));
+}
+
+
+
+static void
+_lcd_write_char (uint8_t c, int x, int y)
+{
+  cm_disable_interrupts ();
+  dma_data (update_buf + dma_offset (x, y), c);
+  cm_enable_interrupts ();
+}
+
+
+void
+lcd_write_char (uint8_t c, int x, int y)
+{
+  cm_disable_interrupts ();
+  _lcd_write_char (c, x, y);
+  cm_enable_interrupts ();
+}
+
+
+void
+lcd_erase (int x, int y, int w)
+{
+  uint8_t *dma_ptr = update_buf + dma_offset (x, y);
+  cm_disable_interrupts ();
+  while (w--)
+    dma_ptr += dma_data (dma_ptr, ' ');
+  cm_enable_interrupts ();
+}
+
+void
+lcd_erase_line (int w, int y)
+{
+  lcd_erase (0, y, w);
+}
+
+void
+lcd_erase_all (void)
+{
+  int y;
+  for (y = 0; y < LCD_H; ++y)
+    {
+      lcd_erase (0, 0, LCD_W);
+    }
+}
+
+void
+lcd_write (char *c, int x, int y)
+{
+  cm_disable_interrupts ();
+  while (*c)
+    {
+      _lcd_write_char (*(c++), x++, y);
+      if (x == LCD_W)
+        break;
+    }
+  cm_enable_interrupts ();
+}
+
+#if 0
+static void
+lcd_scroll (uint8_t * p)
+{
+  int i;
+  for (i = 0; i < 3; ++i)
+    {
+      memcpy (p, p + LCD_RS, LCD_W);
+      p += LCD_RS;
+    }
+  memset (p, ' ', LCD_W);
+}
+
+void
+lcd_putc (uint8_t c)
+{
+
+  switch (c)
+    {
+    case '\r':
+      pos &= ~LCD_W_MASK;
+      break;
+    case '\n':
+      pos &= ~LCD_W_MASK;
+      pos += LCD_RS;
+      break;
+    default:
+      buf[pos] = c;
+      pos++;
+    }
+
+
+  if ((pos & LCD_W_MASK) == LCD_W)
+    {
+      pos &= ~LCD_W_MASK;
+      pos += LCD_RS;
+    }
+
+  if (pos == LCD_SZ)
+    {
+      lcd_scroll (buf);
+      pos -= LCD_RS;
+    }
+
+
+}
+#endif
+
+
+void
+lcd_backlight (int i)
+{
+  backlight = i;
+
+  dma_change_backlight ();
+
+  if (refresh_enabled)
+    return;
+
+  while (i2cp_lock ());
+  i2cp_start_transaction (PCF8574_I2C_ADDRESS, I2C_WRITE);
+  i2cp_send_data (backlight ? LINE_BACKLIGHT : 0);
+  i2cp_stop ();
+  i2cp_unlock ();
+}
+
+
+
+
+
+void
+lcd_enable_refresh (void)
+{
+  refresh_enabled = 1;
+  start_dma ();
+}
+
+
+void
+lcd_disable_refresh (void)
+{
+  refresh_enabled = 0;
+  while (dma_in_progress);
+}
+
+
+
+void
+lcd_reset (void)
+{
+  while (i2cp_lock ());
+  i2cp_start_transaction (PCF8574_I2C_ADDRESS, I2C_WRITE);
+  clock_nibble (0x30);
+  delay_ms (5);
+  clock_nibble (0x30);
+  delay_us (64);
+  clock_nibble (0x30);
+  delay_us (64);
+  clock_nibble (0x20);
+
+  send_command (LCD_FUNC | LCD_FUNC_4BIT | LCD_FUNC_2ROWS | LCD_FUNC_5X7);
+  i2cp_stop ();
+  i2cp_unlock ();
+
+  on ();
+  cls ();
+}
+
+void
+lcd_init (void)
+{
+  lcd_backlight (0);
+  lcd_reset ();
+  lcd_backlight (1);
+
+  dma_generate_stream ();
+
+  nvic_enable_irq (NVIC_DMA1_CHANNEL6_IRQ);
+  lcd_enable_refresh ();
+}
+
+void
+lcd_shutdown (void)
+{
+  lcd_disable_refresh ();
+  lcd_backlight (0);
+  off ();
+}
diff --git a/app/led.c b/app/led.c
new file mode 100644
index 0000000..64c4660
--- /dev/null
+++ b/app/led.c
@@ -0,0 +1,48 @@
+#include "project.h"
+
+
+static int led = 0;
+
+void
+led_init (void)
+{
+  gpio_set_mode (GPIOB, GPIO_MODE_OUTPUT_2_MHZ,
+                 GPIO_CNF_OUTPUT_PUSHPULL, GPIO8);
+  gpio_set_mode (GPIOB, GPIO_MODE_OUTPUT_2_MHZ,
+                 GPIO_CNF_OUTPUT_PUSHPULL, GPIO9);
+}
+
+
+void
+led_clear (void)
+{
+  gpio_set (GPIOB, GPIO8);
+  gpio_set (GPIOB, GPIO9);
+}
+
+void
+led_set (uint32_t v)
+{
+  gpio_clear (GPIOB, v);
+  led = 200;
+}
+
+void
+led_tick (void)
+{
+  static int c;
+
+  if (led)
+    {
+      led--;
+      if (!led)
+        led_clear ();
+    }
+  else
+    {
+      led_set (c ? GPIO8 : GPIO9);
+      c ^= 1;
+    }
+
+
+}
diff --git a/app/main.c b/app/main.c
new file mode 100644
index 0000000..84edc6f
--- /dev/null
+++ b/app/main.c
@@ -0,0 +1,58 @@
+#include "project.h"
+
+
+static void
+kbd_dispatch (void)
+{
+  uint8_t c;
+
+  if (ring_read_byte (&rx1_ring, &c))
+    return;
+
+  printf("KEY> %c\r\n",c);
+
+}
+
+int
+main (void)
+{
+//  rcc_clock_setup_in_hsi_out_48mhz ();
+  //nvic_set_priority_grouping(NVIC_PriorityGroup_4);
+
+  /*set up pll */
+  rcc_clock_setup_in_hse_8mhz_out_72mhz ();
+
+  /*turn on clocks which aren't done elsewhere */
+  rcc_periph_clock_enable (RCC_GPIOA);
+  rcc_periph_clock_enable (RCC_GPIOB);
+  rcc_periph_clock_enable (RCC_GPIOC);
+  rcc_periph_clock_enable (RCC_AFIO);
+
+
+  /*Adjust interrupt priorities so that uarts trump timer */
+  nvic_set_priority (NVIC_USART1_IRQ, 0x40);
+  nvic_set_priority (NVIC_USART2_IRQ, 0x40);
+  nvic_set_priority (NVIC_USART3_IRQ, 0x40);
+  nvic_set_priority (NVIC_SYSTICK_IRQ, 0xff);
+
+
+  ticker_init ();
+
+  led_init ();
+  usart_init ();
+  i2cp_init ();
+
+  lcd_init ();
+
+
+  lcd_write ("Hello world", 0, 0);
+
+  for (;;)
+    {
+      if (!ring_empty (&rx1_ring))
+        kbd_dispatch ();
+
+    }
+
+  return 0;
+}
diff --git a/app/project.h b/app/project.h
new file mode 100644
index 0000000..89184aa
--- /dev/null
+++ b/app/project.h
@@ -0,0 +1,21 @@
+#include <stdlib.h>
+#include <string.h>
+#include <strings.h>
+#include <libopencm3/stm32/rcc.h>
+#include <libopencm3/stm32/gpio.h>
+#include <libopencm3/stm32/usart.h>
+#include <libopencm3/stm32/dma.h>
+#include <libopencm3/stm32/i2c.h>
+#include <libopencm3/cm3/systick.h>
+#include <libopencm3/cm3/nvic.h>
+#include <libopencm3/cm3/cortex.h>
+
+
+#include <stdio.h>
+#include <errno.h>
+
+#include "i2c.h"
+
+#include "ring.h"
+
+#include "prototypes.h"
diff --git a/app/prototypes.h b/app/prototypes.h
new file mode 100644
index 0000000..2e0163c
--- /dev/null
+++ b/app/prototypes.h
@@ -0,0 +1,63 @@
+/* i2c.c */
+extern void i2c_clear_start(uint32_t i2c);
+extern void i2cp_start(void);
+extern void i2cp_abort_start(void);
+extern void i2cp_stop(void);
+extern void i2cp_abort_stop(void);
+extern int i2cp_send_data(uint8_t v);
+extern int i2cp_start_transaction(uint8_t a, int wnr);
+extern int i2cp_lock(void);
+extern void i2cp_unlock(void);
+extern void i2cp_start_dma(uint8_t *buf, int len);
+extern int i2cp_dma_in_progress(void);
+extern void i2cp_stop_dma(void);
+extern void i2cp_reset(void);
+extern void i2cp_scan(void);
+extern void i2cp_init(void);
+/* lcd.c */
+extern uint32_t refresh_wdt;
+extern void dma1_channel6_isr(void);
+extern void lcd_refresh_wdt(void);
+extern void lcd_write_char(uint8_t c, int x, int y);
+extern void lcd_erase(int x, int y, int w);
+extern void lcd_erase_line(int w, int y);
+extern void lcd_erase_all(void);
+extern void lcd_write(char *c, int x, int y);
+extern void lcd_backlight(int i);
+extern void lcd_enable_refresh(void);
+extern void lcd_disable_refresh(void);
+extern void lcd_reset(void);
+extern void lcd_init(void);
+extern void lcd_shutdown(void);
+/* led.c */
+extern void led_init(void);
+extern void led_clear(void);
+extern void led_set(uint32_t v);
+extern void led_tick(void);
+/* main.c */
+extern int main(void);
+/* ring.c */
+extern void ring_init(ring_t *r, uint8_t *buf, size_t len);
+extern int ring_write_byte(ring_t *r, uint8_t c);
+extern int ring_read_byte(ring_t *r, uint8_t *c);
+extern int ring_write(ring_t *r, uint8_t *buf, size_t len);
+extern int ring_empty(ring_t *r);
+/* ticker.c */
+extern uint32_t ticks;
+extern void delay_us(uint32_t d);
+extern void sys_tick_handler(void);
+extern void delay_ms(uint32_t d);
+extern void ticker_init(void);
+/* usart.c */
+extern ring_t rx1_ring;
+extern ring_t tx1_ring;
+extern ring_t rx2_ring;
+extern ring_t tx2_ring;
+extern void usart1_isr(void);
+extern void usart2_isr(void);
+extern int _write(int file, char *ptr, int len);
+extern void usart1_queue(uint8_t d);
+extern void usart2_queue(uint8_t d);
+extern void usart2_drain(void);
+extern void usart1_drain(void);
+extern void usart_init(void);
diff --git a/app/ring.c b/app/ring.c
new file mode 100644
index 0000000..c4f3458
--- /dev/null
+++ b/app/ring.c
@@ -0,0 +1,68 @@
+#include "project.h"
+
+
+static inline size_t
+ring_next (ring_t * r, size_t p)
+{
+  p++;
+  if (p >= r->size)
+    p -= r->size;
+  return p;
+}
+
+void
+ring_init (ring_t * r, uint8_t * buf, size_t len)
+{
+  r->data = buf;
+  r->size = len;
+  r->write = 0;
+  r->read = 0;
+}
+
+int
+ring_write_byte (ring_t * r, uint8_t c)
+{
+  size_t n = ring_next (r, r->write);
+
+  if (n == r->read)
+    return -1;
+
+  r->data[r->write] = c;
+
+  r->write = n;
+
+  return 0;
+}
+
+
+int
+ring_read_byte (ring_t * r, uint8_t * c)
+{
+  size_t n = ring_next (r, r->read);
+
+  if (r->read == r->write)
+    return -1;
+
+  *c = r->data[r->read];
+  r->read = n;
+
+  return 0;
+}
+
+int
+ring_write (ring_t * r, uint8_t * buf, size_t len)
+{
+  while (len--)
+    {
+      if (ring_write_byte (r, *(buf++)))
+        return -1;
+    }
+
+  return 0;
+}
+
+int
+ring_empty (ring_t * r)
+{
+  return (r->read == r->write) ? 1 : 0;
+}
diff --git a/app/ring.h b/app/ring.h
new file mode 100644
index 0000000..ba8887b
--- /dev/null
+++ b/app/ring.h
@@ -0,0 +1,7 @@
+typedef struct ring
+{
+  uint8_t *data;
+  size_t size;
+  size_t write;
+  size_t read;
+} ring_t;
diff --git a/app/ticker.c b/app/ticker.c
new file mode 100644
index 0000000..6ffff31
--- /dev/null
+++ b/app/ticker.c
@@ -0,0 +1,51 @@
+#include "project.h"
+
+static volatile uint32_t delay_ms_count;
+uint32_t ticks;
+
+void
+delay_us (uint32_t d)
+{
+  d *= 36;
+  while (d--)
+    {
+      __asm__ ("nop");
+    }
+}
+
+void
+sys_tick_handler (void)
+{
+  if (delay_ms_count)
+    delay_ms_count--;
+
+  ticks++;
+
+  led_tick ();
+  lcd_refresh_wdt ();
+}
+
+
+
+void
+delay_ms (uint32_t d)
+{
+  delay_ms_count = d;
+  while (delay_ms_count);
+}
+
+
+void
+ticker_init (void)
+{
+
+  /*Start periodic timer */
+  systick_set_clocksource (STK_CSR_CLKSOURCE_AHB_DIV8);
+  /* 48MHz / 8 = > 6Mhz */
+  systick_set_reload (6000);
+  /* 6MHz / 6000 => 1kHz */
+  systick_interrupt_enable ();
+  systick_counter_enable ();
+
+
+}
diff --git a/app/usart.c b/app/usart.c
new file mode 100644
index 0000000..e0a80b1
--- /dev/null
+++ b/app/usart.c
@@ -0,0 +1,191 @@
+#include "project.h"
+
+#define BUFFER_SIZE 256
+#define BIG_BUFFER_SIZE 600
+
+ring_t rx1_ring;
+static uint8_t rx1_ring_buf[BUFFER_SIZE];
+
+ring_t tx1_ring;
+static uint8_t tx1_ring_buf[BUFFER_SIZE];
+
+ring_t rx2_ring;
+static uint8_t rx2_ring_buf[BUFFER_SIZE];
+
+ring_t tx2_ring;
+static uint8_t tx2_ring_buf[BIG_BUFFER_SIZE];
+
+void
+usart1_isr (void)
+{
+  uint8_t data;
+
+  /* Check if we were called because of RXNE. */
+  if (((USART_CR1 (USART1) & USART_CR1_RXNEIE) != 0) &&
+      ((USART_SR (USART1) & USART_SR_RXNE) != 0))
+    {
+
+      /* Retrieve the data from the peripheral. */
+      data = usart_recv (USART1);
+
+
+      ring_write_byte (&rx1_ring, data);
+    }
+
+  /* Check if we were called because of TXE. */
+  if (((USART_CR1 (USART1) & USART_CR1_TXEIE) != 0) &&
+      ((USART_SR (USART1) & USART_SR_TXE) != 0))
+    {
+
+      if (ring_read_byte (&tx1_ring, &data))
+        {
+          /*No more data, Disable the TXE interrupt, it's no longer needed. */
+          USART_CR1 (USART1) &= ~USART_CR1_TXEIE;
+        }
+      else
+        {
+          usart_send (USART1, data);
+        }
+    }
+
+}
+
+void
+usart2_isr (void)
+{
+  uint8_t data;
+
+  /* Check if we were called because of RXNE. */
+  if (((USART_CR1 (USART2) & USART_CR1_RXNEIE) != 0) &&
+      ((USART_SR (USART2) & USART_SR_RXNE) != 0))
+    {
+
+      /* Retrieve the data from the peripheral. */
+      data = usart_recv (USART2);
+
+      ring_write_byte (&rx2_ring, data);
+    }
+
+  /* Check if we were called because of TXE. */
+  if (((USART_CR1 (USART2) & USART_CR1_TXEIE) != 0) &&
+      ((USART_SR (USART2) & USART_SR_TXE) != 0))
+    {
+
+      if (ring_read_byte (&tx2_ring, &data))
+        {
+          /*No more data, Disable the TXE interrupt, it's no longer needed. */
+          USART_CR1 (USART2) &= ~USART_CR1_TXEIE;
+        }
+      else
+        {
+          usart_send_blocking (USART2, data);
+        }
+    }
+
+}
+
+int
+_write (int file, char *ptr, int len)
+{
+  int ret;
+
+  if (file == 1)
+    {
+      ret = ring_write (&tx1_ring, (uint8_t *) ptr, len);
+
+      if (ret < 0)
+        ret = -ret;
+
+      USART_CR1 (USART1) |= USART_CR1_TXEIE;
+      return ret;
+    }
+
+  errno = EIO;
+  return -1;
+}
+
+void
+usart1_queue (uint8_t d)
+{
+  ring_write_byte (&tx1_ring, d);
+  USART_CR1 (USART1) |= USART_CR1_TXEIE;
+}
+
+
+void
+usart2_queue (uint8_t d)
+{
+  ring_write_byte (&tx2_ring, d);
+  USART_CR1 (USART2) |= USART_CR1_TXEIE;
+}
+
+void
+usart2_drain (void)
+{
+  while (!ring_empty (&tx2_ring));
+}
+
+void
+usart1_drain (void)
+{
+  while (!ring_empty (&tx1_ring));
+}
+
+
+
+void
+usart_init (void)
+{
+  rcc_periph_clock_enable (RCC_USART1);
+  rcc_periph_clock_enable (RCC_USART2);
+  rcc_periph_clock_enable (RCC_USART3);
+
+  ring_init (&rx1_ring, rx1_ring_buf, sizeof (rx1_ring_buf));
+  ring_init (&tx1_ring, tx1_ring_buf, sizeof (tx1_ring_buf));
+
+  ring_init (&rx2_ring, rx2_ring_buf, sizeof (rx2_ring_buf));
+  ring_init (&tx2_ring, tx2_ring_buf, sizeof (tx2_ring_buf));
+
+
+  /* Enable the USART1,2 interrupt. */
+  nvic_enable_irq (NVIC_USART1_IRQ);
+  nvic_enable_irq (NVIC_USART2_IRQ);
+
+  /* Map pins, and set usart2 to have pull ups */
+  gpio_set_mode (GPIOA, GPIO_MODE_OUTPUT_50_MHZ,
+                 GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART1_TX);
+  gpio_set_mode (GPIOA, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT,
+                 GPIO_USART1_RX);
+
+  gpio_set_mode (GPIOA, GPIO_MODE_OUTPUT_50_MHZ,
+                 GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_USART2_TX);
+  gpio_set_mode (GPIOA, GPIO_MODE_INPUT, GPIO_CNF_INPUT_PULL_UPDOWN,
+                 GPIO_USART2_RX);
+  gpio_set (GPIOA, GPIO_USART2_RX);
+
+
+  /* Setup UART1 parameters. */
+  usart_set_baudrate (USART1, 38400);
+  usart_set_databits (USART1, 8);
+  usart_set_stopbits (USART1, USART_STOPBITS_1);
+  usart_set_parity (USART1, USART_PARITY_NONE);
+  usart_set_flow_control (USART1, USART_FLOWCONTROL_NONE);
+  usart_set_mode (USART1, USART_MODE_TX_RX);
+
+  /* Setup UART2 parameters. */
+  usart_set_baudrate (USART2, 9600);
+  usart_set_databits (USART2, 8);
+  usart_set_stopbits (USART2, USART_STOPBITS_1);
+  usart_set_parity (USART2, USART_PARITY_NONE);
+  usart_set_flow_control (USART2, USART_FLOWCONTROL_NONE);
+  usart_set_mode (USART2, USART_MODE_TX_RX);
+
+
+  /* Enable USART1,2 Receive interrupt. */
+  USART_CR1 (USART1) |= USART_CR1_RXNEIE;
+  USART_CR1 (USART2) |= USART_CR1_RXNEIE;
+
+  /* Finally enable the USARTs. */
+  usart_enable (USART1);
+  usart_enable (USART2);
+}
diff --git a/board/STM32F103R_BOARD.cfg b/board/STM32F103R_BOARD.cfg
new file mode 100644
index 0000000..6d1d72b
--- /dev/null
+++ b/board/STM32F103R_BOARD.cfg
@@ -0,0 +1,3 @@
+#
+
+source [find target/stm32f1x.cfg]
diff --git a/interface/j-link.cfg b/interface/j-link.cfg
new file mode 100644
index 0000000..3e95768
--- /dev/null
+++ b/interface/j-link.cfg
@@ -0,0 +1,5 @@
+#
+telnet_port 4444
+gdb_port 3333
+
+source [find interface/jlink.cfg]
diff --git a/libopencm3 b/libopencm3
new file mode 160000
+Subproject 43e66927fc48ffb9ad90fec275290ea7c0f8878
diff --git a/stm32-f103.cfg b/stm32-f103.cfg
new file mode 100644
index 0000000..0809223
--- /dev/null
+++ b/stm32-f103.cfg
@@ -0,0 +1,6 @@
+#
+telnet_port 4444
+gdb_port 3333
+
+source [find interface/jlink.cfg]
+source [find target/stm32f1x.cfg]