diff --git a/car_cfmw/.gitignore b/car_cfmw/.gitignore
new file mode 100644
index 00000000000..86c36a2d66f
--- /dev/null
+++ b/car_cfmw/.gitignore
@@ -0,0 +1,2 @@
+tags
+bin
diff --git a/car_cfmw/Makefile b/car_cfmw/Makefile
new file mode 100644
index 00000000000..81b5bbd78bd
--- /dev/null
+++ b/car_cfmw/Makefile
@@ -0,0 +1,70 @@
+SRC_DIR=src
+BIN_DIR=bin
+
+CAR_FMW_OBJ=$(BIN_DIR)/car_fmw.o
+CAR_FMW_ELF=$(BIN_DIR)/car_fmw.elf
+CAR_FMW_BIN=$(BIN_DIR)/car_fmw.bin
+
+LIB_CARHW_DIR=../car_hw/
+LIB_CARHW_OBJ=$(LIB_CARHW_DIR)/bin/car_hw.o
+LIB_CARHW_LIB_DIR=$(LIB_CARHW_DIR)/src/lib/
+
+CC=arm-none-eabi-gcc
+AS=arm-none-eabi-as
+LD=arm-none-eabi-ld
+OBJ_COPY=arm-none-eabi-objcopy
+
+INCLUDES=-I$(LIB_CARHW_LIB_DIR)/cmsis \
+		 -I$(LIB_CARHW_LIB_DIR)/stdperiph \
+		 -I$(LIB_CARHW_LIB_DIR)/stm32f4d \
+		 -I$(LIB_CARHW_LIB_DIR)/usb_device \
+		 -I$(LIB_CARHW_LIB_DIR)/usb_otg \
+		 -I$(LIB_CARHW_LIB_DIR)/usb_vcp \
+		 -I$(LIB_CARHW_LIB_DIR)/usart \
+		 -I$(LIB_CARHW_DIR)/src/include \
+		 -I$(SRC_DIR)
+
+DEFINES=-DUSE_STM32_DISCOVERY=1 -DUSE_STDPERIPH_DRIVER=1 -DSTM32F4XX=1 -DHSE_VALUE=8000000
+CFLAGS=-g -nostdlib -ffreestanding -O0 \
+       -mcpu=cortex-m3 -mfloat-abi=soft -mthumb \
+       $(DEFINES)
+ASMFLAGS=-g -mthumb
+
+LD_ALL_DEPS=$(LD) -r $(filter %.o,$^) -o $@
+CC_ALL_DEPS=$(CC) $(CFLAGS) -c $(INCLUDES) $(filter %.c,$^) -o $@
+AS_ALL_DEPS=$(AS) $(ASMFLAGS) $(filter %.s,$^) -o $@
+
+dirhs=$(wildcard $(1)/*.h)
+dircs=$(wildcard $(1)/*.c)
+dircs_to_prefxd_objs=\
+	$(patsubst $(1)/%.c,$(BIN_DIR)/$(2)%.o,$(call dircs,$1))
+
+CARFMW_OBJ_PREFIX=carfmw_
+
+$(CAR_FMW_BIN): $(CAR_FMW_ELF) $(BIN_DIR)
+	$(OBJ_COPY) -O binary $< $@
+
+$(CAR_FMW_ELF): $(CAR_FMW_OBJ) $(LIB_CARHW_OBJ)
+	$(CC) $(CFLAGS) $^ -T $(SRC_DIR)/stm32_flash.ld -o $@
+
+$(CAR_FMW_OBJ): \
+	$(call dircs_to_prefxd_objs,$(SRC_DIR),$(CARFMW_OBJ_PREFIX))
+	$(LD_ALL_DEPS)
+
+$(BIN_DIR)/$(CARFMW_OBJ_PREFIX)%.o: $(SRC_DIR)/%.c \
+	$(call dirhs,$(SRC_DIR))
+	$(CC_ALL_DEPS)
+
+$(LIB_CARHW_OBJ):
+	make -C $(LIB_CARHW_DIR)
+
+$(BIN_DIR):
+	mkdir -p $(BIN_DIR)
+
+clean:
+	rm -rf bin/*
+
+tags:
+	ctags -R * $(LIB_CARHW_DIR)
+
+.PHONY: clean tags
diff --git a/car_cfmw/README.md b/car_cfmw/README.md
new file mode 100644
index 00000000000..7b7925b0cef
--- /dev/null
+++ b/car_cfmw/README.md
@@ -0,0 +1,2 @@
+Car firmware project for low level experimentation
+using C.
diff --git a/car_cfmw/src/main.c b/car_cfmw/src/main.c
new file mode 100644
index 00000000000..870f2359e94
--- /dev/null
+++ b/car_cfmw/src/main.c
@@ -0,0 +1,101 @@
+#include <car_leds.h>
+#include <car_engine.h>
+#include <car_time.h>
+#include <car_user_btn.h>
+#include <car_conn.h>
+#include <car_sonar.h>
+#include <usart_test.h>
+
+size_t strlen(const char *str)
+{
+    size_t len = 0;
+
+    while (str[len])
+        ++len;
+    return len;
+}
+
+char digit_to_char(uint8_t digit)
+{
+    if (digit <= 9)
+        return '0' + digit;
+    else return 'A' + (digit - 10);
+}
+
+// Should allow to store up to "65535\0"
+char uint16_str[6] = "65535";
+
+char *uint16_to_str(uint16_t val)
+{
+    int dix = 4;
+    for (; dix >= 0; --dix) {
+        uint8_t digit = (uint8_t)(val % 10);
+        uint16_str[dix] = digit_to_char(digit);
+        val = val / 10;
+        if (val == 0)
+            break;
+    }
+    if (dix == -1)
+        dix = 0;
+    return &uint16_str[dix];
+}
+
+void sonar_prog_dist_to_conn(void)
+{
+    while (1) {
+        uint16_t dist = 0;
+
+        car_leds_clear_all();
+        dist = car_sonar_get_dist(90);
+
+        if (dist == CAR_SONAR_DIST_ERR)
+            car_led_set(CAR_LED_RED, true);
+        else {
+            car_led_set(CAR_LED_GREEN, true);
+            const char *str = uint16_to_str(dist);
+            car_conn_snd_buf(strlen(str), (int)str);
+            car_conn_snd_byte('\n');
+        }
+        car_time_wait(1000);
+    }
+}
+
+void sonar_prog_rotate(void)
+{
+    uint8_t degree = 0;
+    while (1) {
+        uint16_t dist = 0;
+
+        car_leds_clear_all();
+        dist = car_sonar_get_dist(degree);
+        if (degree == 0 ||
+            degree == 45 ||
+            degree == 90 ||
+            degree == (90 + 45) ||
+            degree == 180)
+            car_time_wait(500);
+
+        degree += 5;
+        if (degree > 180)
+            degree = 0;
+        if (dist == CAR_SONAR_DIST_ERR)
+            car_led_set(CAR_LED_RED, true);
+        else
+            car_led_set(CAR_LED_GREEN, true);
+        car_time_wait(300);
+    }
+}
+
+int main(void)
+{
+    car_time_init();
+    car_leds_init();
+    car_engine_init();
+    car_user_btn_init(NULL);
+    car_conn_init();
+    car_sonar_init();
+
+    sonar_prog_rotate();
+    //sonar_prog_dist_to_conn();
+    // Also we can run usart test from here
+}
diff --git a/car_cfmw/src/stm32_flash.ld b/car_cfmw/src/stm32_flash.ld
new file mode 100644
index 00000000000..9a10d57b3c1
--- /dev/null
+++ b/car_cfmw/src/stm32_flash.ld
@@ -0,0 +1,177 @@
+/*
+*****************************************************************************
+**
+**  File        : stm32_flash.ld
+**
+**  Abstract    : Linker script for STM32F407VG Device with
+**                1024KByte FLASH, 192KByte RAM
+**
+**                Set heap size, stack size and stack location according
+**                to application requirements.
+**
+**                Set memory bank area and size if external memory is used.
+**
+**  Target      : STMicroelectronics STM32
+**
+**  Environment : Atollic TrueSTUDIO(R)
+**
+**  Distribution: The file is distributed “as is,” without any warranty
+**                of any kind.
+**
+**  (c)Copyright Atollic AB.
+**  You may use this file as-is or modify it according to the needs of your
+**  project. Distribution of this file (unmodified or modified) is not
+**  permitted. Atollic AB permit registered Atollic TrueSTUDIO(R) users the
+**  rights to distribute the assembled, compiled & linked contents of this
+**  file as part of an application binary file, provided that it is built
+**  using the Atollic TrueSTUDIO(R) toolchain.
+**
+*****************************************************************************
+*/
+
+/* Entry Point */
+ENTRY(Reset_Handler)
+
+/*
+ * _estack is the highest address of user mode stack
+ * (sp initial value, stack grows down).
+ * We have 192K RAM on our MCU and _estack should be 0x20030000.
+ * But our MCU maps only 128K SRAM at 0x20000000 after boot.
+ * We need to perform some memory remapping to use more.
+ * This isn't implemented yet.
+ */
+_estack = 0x20020000; /* end of 128K SRAM region */
+
+/* Generate a link error if heap and stack don't fit into RAM */
+_Min_Heap_Size = 0;      /* required amount of heap  */
+_Min_Stack_Size = 0x400; /* required amount of stack */
+
+/* Specify the memory areas */
+MEMORY
+{
+  FLASH (rx)      : ORIGIN = 0x08000000, LENGTH = 1024K
+  RAM (xrw)       : ORIGIN = 0x20000000, LENGTH = 128K
+  MEMORY_B1 (rx)  : ORIGIN = 0x60000000, LENGTH = 0K
+}
+
+/* Define output sections */
+SECTIONS
+{
+  /* The startup code goes first into FLASH */
+  .isr_vector :
+  {
+    . = ALIGN(4);
+    KEEP(*(.isr_vector)) /* Startup code */
+    . = ALIGN(4);
+  } >FLASH
+
+  /* The program code and other data goes into FLASH */
+  .text :
+  {
+    . = ALIGN(4);
+    *(.text)           /* .text sections (code) */
+    *(.text*)          /* .text* sections (code) */
+    *(.rodata)         /* .rodata sections (constants, strings, etc.) */
+    *(.rodata*)        /* .rodata* sections (constants, strings, etc.) */
+    *(.glue_7)         /* glue arm to thumb code */
+    *(.glue_7t)        /* glue thumb to arm code */
+	*(.eh_frame)
+
+    KEEP (*(.init))
+    KEEP (*(.fini))
+
+    . = ALIGN(4);
+    _etext = .;        /* define a global symbols at end of code */
+  } >FLASH
+
+
+   .ARM.extab   : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH
+    .ARM : {
+    __exidx_start = .;
+      *(.ARM.exidx*)
+      __exidx_end = .;
+    } >FLASH
+
+  .preinit_array     :
+  {
+    PROVIDE_HIDDEN (__preinit_array_start = .);
+    KEEP (*(.preinit_array*))
+    PROVIDE_HIDDEN (__preinit_array_end = .);
+  } >FLASH
+  .init_array :
+  {
+    PROVIDE_HIDDEN (__init_array_start = .);
+    KEEP (*(SORT(.init_array.*)))
+    KEEP (*(.init_array*))
+    PROVIDE_HIDDEN (__init_array_end = .);
+  } >FLASH
+  .fini_array :
+  {
+    PROVIDE_HIDDEN (__fini_array_start = .);
+    KEEP (*(.fini_array*))
+    KEEP (*(SORT(.fini_array.*)))
+    PROVIDE_HIDDEN (__fini_array_end = .);
+  } >FLASH
+
+  /* used by the startup to initialize data */
+  _sidata = .;
+
+  /* Initialized data sections goes into RAM, load LMA copy after code */
+  .data : AT ( _sidata )
+  {
+    . = ALIGN(4);
+    _sdata = .;        /* create a global symbol at data start */
+    *(.data)           /* .data sections */
+    *(.data*)          /* .data* sections */
+
+    . = ALIGN(4);
+    _edata = .;        /* define a global symbol at data end */
+  } >RAM
+
+  /* Uninitialized data section */
+  . = ALIGN(4);
+  .bss :
+  {
+    /* This is used by the startup in order to initialize the .bss secion */
+    _sbss = .;         /* define a global symbol at bss start */
+    __bss_start__ = _sbss;
+    *(.bss)
+    *(.bss*)
+    *(COMMON)
+
+    . = ALIGN(4);
+    _ebss = .;         /* define a global symbol at bss end */
+    __bss_end__ = _ebss;
+  } >RAM
+
+  /* User_heap_stack section, used to check that there is enough RAM left */
+  ._user_heap_stack :
+  {
+    . = ALIGN(4);
+    PROVIDE ( end = . );
+    PROVIDE ( _end = . );
+    . = . + _Min_Heap_Size;
+    . = . + _Min_Stack_Size;
+    . = ALIGN(4);
+  } >RAM
+
+  /* MEMORY_bank1 section, code must be located here explicitly            */
+  /* Example: extern int foo(void) __attribute__ ((section (".mb1text"))); */
+  .memory_b1_text :
+  {
+    *(.mb1text)        /* .mb1text sections (code) */
+    *(.mb1text*)       /* .mb1text* sections (code)  */
+    *(.mb1rodata)      /* read-only data (constants) */
+    *(.mb1rodata*)
+  } >MEMORY_B1
+
+  /* Remove information from the standard libraries */
+  /DISCARD/ :
+  {
+    libc.a ( * )
+    libm.a ( * )
+    libgcc.a ( * )
+  }
+
+  .ARM.attributes 0 : { *(.ARM.attributes) }
+}
diff --git a/car_hw/Makefile b/car_hw/Makefile
index 3e96486f015..0e7b193bb1b 100644
--- a/car_hw/Makefile
+++ b/car_hw/Makefile
@@ -9,6 +9,7 @@ LIB_STM32F4D_DIR=$(LIB_DIR)/stm32f4d
 LIB_USB_DEV_DIR=$(LIB_DIR)/usb_device
 LIB_USB_OTG_DIR=$(LIB_DIR)/usb_otg
 LIB_USB_VCP_DIR=$(LIB_DIR)/usb_vcp
+LIB_USART_DIR=$(LIB_DIR)/usart
 
 LIB_CMSIS_OBJ=$(BIN_DIR)/libcmsis.o
 LIB_STDPERIPH_OBJ=$(BIN_DIR)/libstdperiph.o
@@ -16,6 +17,7 @@ LIB_STM32F4D_OBJ=$(BIN_DIR)/libstm32f4d.o
 LIB_USB_DEV_OBJ=$(BIN_DIR)/libusbdevice.o
 LIB_USB_OTG_OBJ=$(BIN_DIR)/libusbotg.o
 LIB_USB_VCP_OBJ=$(BIN_DIR)/libusbvcp.o
+LIB_USART_OBJ=$(BIN_DIR)/libusart.o
 
 CARHW_OBJ=$(BIN_DIR)/car_hw.o
 
@@ -32,6 +34,7 @@ INCLUDES=-I$(LIB_CMSIS_DIR) \
 		 -I$(LIB_USB_DEV_DIR) \
 		 -I$(LIB_USB_OTG_DIR) \
 		 -I$(LIB_USB_VCP_DIR) \
+		 -I$(LIB_USART_DIR) \
 		 -I$(USB_CONF_DIR) \
 		 -I$(SRC_DIR) \
 		 -I$(SRC_DIR)/include
@@ -57,7 +60,7 @@ CAR_OBJ_PREFIX=car_
 $(CARHW_OBJ): $(CAR_OBJ) $(LIB_STM32F4D_OBJ) \
 		$(LIB_CMSIS_OBJ) $(LIB_STDPERIPH_OBJ) \
 		$(LIB_USB_DEV_OBJ) $(LIB_USB_OTG_OBJ) \
-		$(LIB_USB_VCP_OBJ)
+		$(LIB_USB_VCP_OBJ) $(LIB_USART_OBJ)
 	$(LD) -r $^ -o $@
 
 $(CAR_OBJ): \
diff --git a/car_hw/src/car_sonar.c b/car_hw/src/car_sonar.c
new file mode 100644
index 00000000000..481bb3060a0
--- /dev/null
+++ b/car_hw/src/car_sonar.c
@@ -0,0 +1,64 @@
+#include <car_sonar.h>
+#include <car_time.h>
+#include <usart.h>
+
+/*
+ * Sonar reference:
+ * http://www.dfrobot.com/wiki/index.php?title=URM37_V4.0_Ultrasonic_Sensor_(SKU:SEN0001)
+ */
+
+static uint8_t sonar_degree(uint8_t degree)
+{
+    // urm37 accepts values [0;46]
+    // so we have 47 steps.
+    // But we don't use the last 46 value.
+    // It gives us angle > 180.
+    if (degree > 180)
+        degree = 180;
+    return degree / 4;
+}
+
+#define SONAR_CMD_GET_DIST 0x22
+
+static uint8_t sonar_cmd[4];
+static void sonar_snd_dist_req(uint8_t rot_degree)
+{
+    size_t i = 0;
+    sonar_cmd[0] = SONAR_CMD_GET_DIST;
+    sonar_cmd[1] = sonar_degree(rot_degree);
+    sonar_cmd[2] = sonar_cmd[3] = 0;
+
+    for (; i < 3; ++i)
+        sonar_cmd[3] += sonar_cmd[i];
+    usart_send_data(USART3_ID, sonar_cmd, 4);
+}
+
+static uint8_t sonar_resp[4];
+static uint16_t sonar_wait_dist_resp(void)
+{
+    size_t i = 0;
+    uint8_t sum = 0;
+
+    usart_rcv_data(USART3_ID, sonar_resp, 4);
+    sum = sonar_resp[0] + sonar_resp[1] + sonar_resp[2];
+    if ((sonar_resp[0] != SONAR_CMD_GET_DIST)
+            || (sum != sonar_resp[3]))
+        return CAR_SONAR_DIST_ERR;
+
+    return ((uint16_t)sonar_resp[1] << 8) + sonar_resp[2];
+}
+
+uint16_t car_sonar_get_dist(uint8_t rot_degree)
+{
+    sonar_snd_dist_req(rot_degree);
+    return sonar_wait_dist_resp();
+}
+
+void car_sonar_init(void)
+{
+    usart_init(USART3_ID);
+    // Sonar boots in ~2.2 secs
+    car_time_wait(3000);
+    // Some really needed magical tweak
+    sonar_snd_dist_req(0);
+}
diff --git a/car_hw/src/include/car_sonar.h b/car_hw/src/include/car_sonar.h
new file mode 100644
index 00000000000..aa192e11d73
--- /dev/null
+++ b/car_hw/src/include/car_sonar.h
@@ -0,0 +1,24 @@
+#pragma once
+
+#include <stdint.h>
+
+/*
+ *       Pins commutation:
+ *    MCU   |  URM37 |  Servo  |
+ *  ----------------------------
+ *    PC11  |  TXD   |    -    |
+ *    PC10  |  RXD   |    -    |
+ *    GND   |  GND   |    -    |
+ *    NRST  |  NRST  |    -    |
+ *    5V    |  +5V   |    -    |
+ *      -   |  MOTO  |  Orange |
+ *    GND   |    -   |  Brown  |
+ *    5V    |    -   |  Red    |
+ */
+
+#define CAR_SONAR_DIST_ERR 0xffff
+
+void car_sonar_init(void);
+// returns CAR_SONAR_DIST_ERR on error
+// else distance in centimeters
+uint16_t car_sonar_get_dist(uint8_t rot_degree);
diff --git a/car_hw/src/include/stm32f4xx_it.h b/car_hw/src/stm32f4xx_it.h
similarity index 100%
rename from car_hw/src/include/stm32f4xx_it.h
rename to car_hw/src/stm32f4xx_it.h