diff --git a/configs/bambino-200e/scripts/memory.ld b/configs/bambino-200e/scripts/memory.ld
index 02e1f729768..3beb58402bd 100644
--- a/configs/bambino-200e/scripts/memory.ld
+++ b/configs/bambino-200e/scripts/memory.ld
@@ -54,7 +54,7 @@
  * Alignment of the user space FLASH partition is also a critical factor:
  * The user space FLASH partition will be spanned with a single region of
  * size 2**n bytes.  The alignment of the user-space region must be the same.
- * As a consequence, as the user-space increases in size, the alignmment
+ * As a consequence, as the user-space increases in size, the alignment
  * requirement also increases.
  *
  * This alignment requirement means that the largest user space FLASH region
diff --git a/configs/clicker2-stm32/scripts/memory.ld b/configs/clicker2-stm32/scripts/memory.ld
index 8a67bca4cd4..99b2a1c5852 100644
--- a/configs/clicker2-stm32/scripts/memory.ld
+++ b/configs/clicker2-stm32/scripts/memory.ld
@@ -54,7 +54,7 @@
  * Alignment of the user space FLASH partition is also a critical factor:
  * The user space FLASH partition will be spanned with a single region of
  * size 2**n bytes.  The alignment of the user-space region must be the same.
- * As a consequence, as the user-space increases in size, the alignmment
+ * As a consequence, as the user-space increases in size, the alignment
  * requirement also increases.
  *
  * This alignment requirement means that the largest user space FLASH region
diff --git a/configs/mikroe-stm32f4/scripts/memory.ld b/configs/mikroe-stm32f4/scripts/memory.ld
index 3a7480d8714..f81320551a5 100644
--- a/configs/mikroe-stm32f4/scripts/memory.ld
+++ b/configs/mikroe-stm32f4/scripts/memory.ld
@@ -54,7 +54,7 @@
  * Alignment of the user space FLASH partition is also a critical factor:
  * The user space FLASH partition will be spanned with a single region of
  * size 2**n bytes.  The alignment of the user-space region must be the same.
- * As a consequence, as the user-space increases in size, the alignmment
+ * As a consequence, as the user-space increases in size, the alignment
  * requirement also increases.
  *
  * This alignment requirement means that the largest user space FLASH region
diff --git a/configs/omnibusf4/scripts/memory.ld b/configs/omnibusf4/scripts/memory.ld
index ea90262f57f..cdd73958b2c 100644
--- a/configs/omnibusf4/scripts/memory.ld
+++ b/configs/omnibusf4/scripts/memory.ld
@@ -54,7 +54,7 @@
  * Alignment of the user space FLASH partition is also a critical factor:
  * The user space FLASH partition will be spanned with a single region of
  * size 2**n bytes.  The alignment of the user-space region must be the same.
- * As a consequence, as the user-space increases in size, the alignmment
+ * As a consequence, as the user-space increases in size, the alignment
  * requirement also increases.
  *
  * This alignment requirement means that the largest user space FLASH region
diff --git a/configs/open1788/scripts/memory.ld b/configs/open1788/scripts/memory.ld
index bf075975a8f..efbaf6d10d0 100644
--- a/configs/open1788/scripts/memory.ld
+++ b/configs/open1788/scripts/memory.ld
@@ -48,7 +48,7 @@
  * Alignment of the user space FLASH partition is a critical factor: The
  * user space FLASH partition will be spanned with a single region of size
  * 2**n bytes.  The alignment of the user-space region must be the same.  As
- * a consequence, as the user-space increases in size, the alignmment
+ * a consequence, as the user-space increases in size, the alignment
  * requirement also increases.
  *
  * This alignment requirement means that the largest user space FLASH region
diff --git a/configs/sam3u-ek/scripts/memory.ld b/configs/sam3u-ek/scripts/memory.ld
index 70369776b4b..5f40295e950 100644
--- a/configs/sam3u-ek/scripts/memory.ld
+++ b/configs/sam3u-ek/scripts/memory.ld
@@ -47,7 +47,7 @@
  * Alignment of the user space FLASH partition is a critical factor: The
  * user space FLASH partition will be spanned with a single region of size
  * 2**n bytes.  The alignment of the user-space region must be the same.  As
- * a consequence, as the user-space increases in size, the alignmment
+ * a consequence, as the user-space increases in size, the alignment
  * requirement also increases.
  *
  * This alignment requirement means that the largest user space FLASH region
diff --git a/configs/stm3240g-eval/scripts/memory.ld b/configs/stm3240g-eval/scripts/memory.ld
index a1b347ccb4f..585bce95595 100644
--- a/configs/stm3240g-eval/scripts/memory.ld
+++ b/configs/stm3240g-eval/scripts/memory.ld
@@ -54,7 +54,7 @@
  * Alignment of the user space FLASH partition is also a critical factor:
  * The user space FLASH partition will be spanned with a single region of
  * size 2**n bytes.  The alignment of the user-space region must be the same.
- * As a consequence, as the user-space increases in size, the alignmment
+ * As a consequence, as the user-space increases in size, the alignment
  * requirement also increases.
  *
  * This alignment requirement means that the largest user space FLASH region
diff --git a/configs/stm32f429i-disco/scripts/memory.ld b/configs/stm32f429i-disco/scripts/memory.ld
index df11b9e3d60..da7bb9c1229 100644
--- a/configs/stm32f429i-disco/scripts/memory.ld
+++ b/configs/stm32f429i-disco/scripts/memory.ld
@@ -55,7 +55,7 @@
  * Alignment of the user space FLASH partition is also a critical factor:
  * The user space FLASH partition will be spanned with a single region of
  * size 2**n bytes.  The alignment of the user-space region must be the same.
- * As a consequence, as the user-space increases in size, the alignmment
+ * As a consequence, as the user-space increases in size, the alignment
  * requirement also increases.
  *
  * This alignment requirement means that the largest user space FLASH region
diff --git a/configs/stm32f4discovery/scripts/memory.ld b/configs/stm32f4discovery/scripts/memory.ld
index 3a7480d8714..f81320551a5 100644
--- a/configs/stm32f4discovery/scripts/memory.ld
+++ b/configs/stm32f4discovery/scripts/memory.ld
@@ -54,7 +54,7 @@
  * Alignment of the user space FLASH partition is also a critical factor:
  * The user space FLASH partition will be spanned with a single region of
  * size 2**n bytes.  The alignment of the user-space region must be the same.
- * As a consequence, as the user-space increases in size, the alignmment
+ * As a consequence, as the user-space increases in size, the alignment
  * requirement also increases.
  *
  * This alignment requirement means that the largest user space FLASH region
diff --git a/configs/stm32l4r9ai-disco/include/board.h b/configs/stm32l4r9ai-disco/include/board.h
index 526d7202e6c..c1c845734af 100644
--- a/configs/stm32l4r9ai-disco/include/board.h
+++ b/configs/stm32l4r9ai-disco/include/board.h
@@ -77,11 +77,14 @@
 #endif
 
 /* ADC measurements
- * Default is ADC1_IN9 (PA4) connected to STMod+ connector CN1 pin 13.
+ *
+ * Some of the choices are:
+ *   ADC1_IN9 (PA4) connected to STMod+ connector CN1 pin 13.
+ *   ADC1_IN12 (PA7) connected to Arduino A0.
  */
 
-#define ADC1_MEASURE_CHANNEL     9
-#define GPIO_MEASURE_ADC         (GPIO_ADC1_IN9)
+#define ADC1_MEASURE_CHANNEL     12
+#define GPIO_MEASURE_ADC         (GPIO_ADC1_IN12)
 
 /* Alternate function pin selections ************************************************/
 
@@ -119,7 +122,7 @@
 
 /* I2C
  *
- * The optional _GPIO configurations allow the I2C driver to manually
+ * The optional GPIO configurations allow the I2C driver to manually
  * reset the bus to clear stuck slaves.  They match the pin configuration,
  * but are normally-high GPIOs.
  *
@@ -131,24 +134,24 @@
  */
 
 #define GPIO_I2C1_SCL    (GPIO_I2C1_SCL_1|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET)
-#define GPIO_I2C1_SDA    (GPIO_I2C1_SDA_1|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET)
+#define GPIO_I2C1_SDA    (GPIO_I2C1_SDA_3|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET)
 #define GPIO_I2C1_SCL_GPIO \
    (GPIO_OUTPUT|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET|GPIO_PORTB|GPIO_PIN6)
 #define GPIO_I2C1_SDA_GPIO \
-   (GPIO_OUTPUT|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET|GPIO_PORTB|GPIO_PIN7)
+   (GPIO_OUTPUT|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET|GPIO_PORTG|GPIO_PIN13)
 
 /* XXX Is I2C2 used on Disco? */
 
-#if 0
+/* I2C3 connects to Arduino Uno V3 connector pins D15 (I2C3_SCL) and D14 (I2C3_SDA). */
 
-#define GPIO_I2C2_SCL    (GPIO_I2C2_SCL_1|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET)
-#define GPIO_I2C2_SDA    (GPIO_I2C2_SDA_1|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET)
-#define GPIO_I2C2_SCL_GPIO \
-   (GPIO_OUTPUT|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET|GPIO_PORTB|GPIO_PIN10)
-#define GPIO_I2C2_SDA_GPIO \
-   (GPIO_OUTPUT|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET|GPIO_PORTB|GPIO_PIN11)
+#define GPIO_I2C3_SCL    (GPIO_I2C3_SCL_2|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET)
+#define GPIO_I2C3_SDA    (GPIO_I2C3_SDA_2|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET)
+#define GPIO_I2C3_SCL_GPIO \
+   (GPIO_OUTPUT|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET|GPIO_PORTG|GPIO_PIN7)
+#define GPIO_I2C3_SDA_GPIO \
+   (GPIO_OUTPUT|GPIO_OPENDRAIN|GPIO_SPEED_50MHz|GPIO_OUTPUT_SET|GPIO_PORTG|GPIO_PIN8)
 
-#endif
+/* XXX Is I2C4 used on Disco? */
 
 /* SPI */
 
@@ -158,11 +161,35 @@
 #define GPIO_SPI1_MOSI   GPIO_SPI1_MOSI_1
 #define GPIO_SPI1_SCK    GPIO_SPI1_SCK_1
 
-/* XXX is SPI2 used on Disco? */
+/* SPI2 connects to Arduino Uno V3 connector pins D10-D13,
+ * also to DSI display.
+ */
 
-#define GPIO_SPI2_MISO   GPIO_SPI2_MISO_3
-#define GPIO_SPI2_MOSI   GPIO_SPI2_MOSI_3
-#define GPIO_SPI2_SCK    GPIO_SPI2_SCK_3
+#define GPIO_SPI2_MISO   GPIO_SPI2_MISO_1
+#define GPIO_SPI2_MOSI   GPIO_SPI2_MOSI_1
+#define GPIO_SPI2_SCK    GPIO_SPI2_SCK_1
+
+/* XXX is SPI3 used on Disco? */
+
+#if 0
+#define GPIO_SPI3_MISO   GPIO_SPI3_MISO_3
+#define GPIO_SPI3_MOSI   GPIO_SPI3_MOSI_3
+#define GPIO_SPI3_SCK    GPIO_SPI3_SCK_3
+#endif
+
+/* DFSDM1
+ *
+ * DFSDM is connected to two MEMS microphones (MP34DT01) by default.
+ *   PC2  -> CKOUT
+ *   PB12 -> DATIN1
+ *   PH2  -> MIC_VDD GPIO
+ */
+
+#define GPIO_DFSDM_DATIN1   GPIO_DFSDM_DATIN1_1
+#define GPIO_DFSDM_CKOUT    GPIO_DFSDM_CKOUT_1
+
+#define GPIO_MIC_VDD       (GPIO_OUTPUT | GPIO_PUSHPULL | GPIO_SPEED_2MHz | \
+                            GPIO_OUTPUT_CLEAR | GPIO_PORTH | GPIO_PIN2)
 
 /* LEDs
  *
diff --git a/configs/stm32l4r9ai-disco/include/stm32l4r9ai-disco-clocking.h b/configs/stm32l4r9ai-disco/include/stm32l4r9ai-disco-clocking.h
index 126d59bba2a..265d1138c27 100644
--- a/configs/stm32l4r9ai-disco/include/stm32l4r9ai-disco-clocking.h
+++ b/configs/stm32l4r9ai-disco/include/stm32l4r9ai-disco-clocking.h
@@ -155,6 +155,10 @@
 
 #define STM32L4_USE_LSE           1
 
+/* HSI16 used as I2C clock */
+
+#define STM32L4_I2C_USE_HSI16     1
+
 /* AHB clock (HCLK) is SYSCLK (120 MHz) */
 
 #define STM32L4_RCC_CFGR_HPRE     RCC_CFGR_HPRE_SYSCLK      /* HCLK  = SYSCLK / 1 */
@@ -261,6 +265,10 @@
 
 #define STM32L4_USE_LSE           1
 
+/* HSI16 used as I2C clock */
+
+#define STM32L4_I2C_USE_HSI16     1
+
 /* Configure the HCLK divisor (for the AHB bus, core, memory, and DMA */
 
 #define STM32L4_RCC_CFGR_HPRE     RCC_CFGR_HPRE_SYSCLK      /* HCLK  = SYSCLK / 1 */
@@ -354,6 +362,10 @@
 
 #define STM32L4_USE_LSE           1
 
+/* HSI16 used as I2C clock */
+
+#define STM32L4_I2C_USE_HSI16     1
+
 /* Configure the HCLK divisor (for the AHB bus, core, memory, and DMA */
 
 #define STM32L4_RCC_CFGR_HPRE     RCC_CFGR_HPRE_SYSCLK      /* HCLK  = SYSCLK / 1 */
diff --git a/configs/stm32l4r9ai-disco/kernel/.gitignore b/configs/stm32l4r9ai-disco/kernel/.gitignore
new file mode 100644
index 00000000000..7bacd5aee3e
--- /dev/null
+++ b/configs/stm32l4r9ai-disco/kernel/.gitignore
@@ -0,0 +1,2 @@
+/nuttx_user.elf
+
diff --git a/configs/stm32l4r9ai-disco/kernel/Makefile b/configs/stm32l4r9ai-disco/kernel/Makefile
new file mode 100644
index 00000000000..103b2c60dd0
--- /dev/null
+++ b/configs/stm32l4r9ai-disco/kernel/Makefile
@@ -0,0 +1,122 @@
+############################################################################
+# configs/stm32l4r9ai-disco/kernel/Makefile
+#
+#   Copyright (C) 2019 Gregory Nutt. All rights reserved.
+#   Author: Gregory Nutt <gnutt@nuttx.org>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in
+#    the documentation and/or other materials provided with the
+#    distribution.
+# 3. Neither the name NuttX nor the names of its contributors may be
+#    used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+############################################################################
+
+-include $(TOPDIR)/Make.defs
+
+# This is the directory for the board-specific header files
+
+BOARD_INCLUDE = $(TOPDIR)$(DELIM)configs$(DELIM)$(CONFIG_ARCH_BOARD)$(DELIM)include
+
+# The entry point name (if none is provided in the .config file)
+
+CONFIG_USER_ENTRYPOINT ?= user_start
+ENTRYPT = $(patsubst "%",%,$(CONFIG_USER_ENTRYPOINT))
+
+# Get the paths to the libraries and the links script path in format that
+# is appropriate for the host OS
+
+ifeq ($(WINTOOL),y)
+  # Windows-native toolchains
+  USER_LIBPATHS = ${shell for path in $(USERLIBS); do dir=`dirname $(TOPDIR)$(DELIM)$$path`;echo "-L\"`cygpath -w $$dir`\"";done}
+  USER_LDSCRIPT = -T "${shell cygpath -w $(TOPDIR)$(DELIM)configs$(DELIM)$(CONFIG_ARCH_BOARD)$(DELIM)scripts$(DELIM)memory.ld}"
+  USER_LDSCRIPT += -T "${shell cygpath -w $(TOPDIR)$(DELIM)configs$(DELIM)$(CONFIG_ARCH_BOARD)$(DELIM)scripts$(DELIM)user-space.ld}"
+  USER_HEXFILE += "${shell cygpath -w $(TOPDIR)$(DELIM)nuttx_user.hex}"
+  USER_SRECFILE += "${shell cygpath -w $(TOPDIR)$(DELIM)nuttx_user.srec}"
+  USER_BINFILE += "${shell cygpath -w $(TOPDIR)$(DELIM)nuttx_user.bin}"
+else
+  # Linux/Cygwin-native toolchain
+  USER_LIBPATHS = $(addprefix -L$(TOPDIR)$(DELIM),$(dir $(USERLIBS)))
+  USER_LDSCRIPT = -T$(TOPDIR)$(DELIM)configs$(DELIM)$(CONFIG_ARCH_BOARD)$(DELIM)scripts$(DELIM)memory.ld
+  USER_LDSCRIPT += -T$(TOPDIR)$(DELIM)configs$(DELIM)$(CONFIG_ARCH_BOARD)$(DELIM)scripts$(DELIM)user-space.ld
+  USER_HEXFILE += "$(TOPDIR)$(DELIM)nuttx_user.hex"
+  USER_SRECFILE += "$(TOPDIR)$(DELIM)nuttx_user.srec"
+  USER_BINFILE += "$(TOPDIR)$(DELIM)nuttx_user.bin"
+endif
+
+USER_LDFLAGS = --undefined=$(ENTRYPT) --entry=$(ENTRYPT) $(USER_LDSCRIPT)
+USER_LDLIBS = $(patsubst lib%,-l%,$(basename $(notdir $(USERLIBS))))
+USER_LIBGCC = "${shell "$(CC)" $(ARCHCPUFLAGS) -print-libgcc-file-name}"
+
+# Source files
+
+CSRCS = stm32l4_userspace.c
+COBJS = $(CSRCS:.c=$(OBJEXT))
+OBJS  = $(COBJS)
+
+# Targets:
+
+all: $(TOPDIR)$(DELIM)nuttx_user.elf $(TOPDIR)$(DELIM)User.map
+.PHONY: nuttx_user.elf depend clean distclean
+
+$(COBJS): %$(OBJEXT): %.c
+	$(call COMPILE, $<, $@)
+
+# Create the nuttx_user.elf file containing all of the user-mode code
+
+nuttx_user.elf: $(OBJS)
+	$(Q) $(LD) -o $@ $(USER_LDFLAGS) $(USER_LIBPATHS) $(OBJS) --start-group $(USER_LDLIBS) --end-group $(USER_LIBGCC)
+
+$(TOPDIR)$(DELIM)nuttx_user.elf: nuttx_user.elf
+	@echo "LD: nuttx_user.elf"
+	$(Q) cp -a nuttx_user.elf $(TOPDIR)$(DELIM)nuttx_user.elf
+ifeq ($(CONFIG_INTELHEX_BINARY),y)
+	@echo "CP: nuttx_user.hex"
+	$(Q) $(OBJCOPY) $(OBJCOPYARGS) -O ihex nuttx_user.elf $(USER_HEXFILE)
+endif
+ifeq ($(CONFIG_MOTOROLA_SREC),y)
+	@echo "CP: nuttx_user.srec"
+	$(Q) $(OBJCOPY) $(OBJCOPYARGS) -O srec nuttx_user.elf $(USER_SRECFILE)
+endif
+ifeq ($(CONFIG_RAW_BINARY),y)
+	@echo "CP: nuttx_user.bin"
+	$(Q) $(OBJCOPY) $(OBJCOPYARGS) -O binary nuttx_user.elf $(USER_BINFILE)
+endif
+
+$(TOPDIR)$(DELIM)User.map: nuttx_user.elf
+	@echo "MK: User.map"
+	$(Q) $(NM) nuttx_user.elf >$(TOPDIR)$(DELIM)User.map
+	$(Q) $(CROSSDEV)size nuttx_user.elf
+
+.depend:
+
+depend: .depend
+
+clean:
+	$(call DELFILE, nuttx_user.elf)
+	$(call DELFILE, "$(TOPDIR)$(DELIM)nuttx_user.*")
+	$(call DELFILE, "$(TOPDIR)$(DELIM)User.map")
+	$(call CLEAN)
+
+distclean: clean
diff --git a/configs/stm32l4r9ai-disco/kernel/stm32l4_userspace.c b/configs/stm32l4r9ai-disco/kernel/stm32l4_userspace.c
new file mode 100644
index 00000000000..3b723e1e3cf
--- /dev/null
+++ b/configs/stm32l4r9ai-disco/kernel/stm32l4_userspace.c
@@ -0,0 +1,132 @@
+/****************************************************************************
+ * configs/stm32l4r9ai-disco/kernel/stm32l4_userspace.c
+ *
+ *   Copyright (C) 2019 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdlib.h>
+
+#include <nuttx/arch.h>
+#include <nuttx/mm/mm.h>
+#include <nuttx/wqueue.h>
+#include <nuttx/userspace.h>
+
+#if defined(CONFIG_BUILD_PROTECTED) && !defined(__KERNEL__)
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/* Configuration ************************************************************/
+
+#ifndef CONFIG_NUTTX_USERSPACE
+#  error "CONFIG_NUTTX_USERSPACE not defined"
+#endif
+
+#if CONFIG_NUTTX_USERSPACE != 0x08020000
+#  error "CONFIG_NUTTX_USERSPACE must be 0x08020000 to match memory.ld"
+#endif
+
+/****************************************************************************
+ * Public Data
+ ****************************************************************************/
+
+/* These 'addresses' of these values are setup by the linker script.  They
+ * are not actual uint32_t storage locations!  They are only used
+ * meaningfully in the following way:
+ *
+ *  - The linker script defines, for example, the symbol_sdata.
+ *  - The declaration extern uint32_t _sdata; makes C happy.  C will believe
+ *    that the value _sdata is the address of a uint32_t variable _data (it is
+ *    not!).
+ *  - We can recover the linker value then by simply taking the address of
+ *    of _data.  like:  uint32_t *pdata = &_sdata;
+ */
+
+extern uint32_t _stext;           /* Start of .text */
+extern uint32_t _etext;           /* End_1 of .text + .rodata */
+extern const uint32_t _eronly;    /* End+1 of read only section (.text + .rodata) */
+extern uint32_t _sdata;           /* Start of .data */
+extern uint32_t _edata;           /* End+1 of .data */
+extern uint32_t _sbss;            /* Start of .bss */
+extern uint32_t _ebss;            /* End+1 of .bss */
+
+/* This is the user space entry point */
+
+int CONFIG_USER_ENTRYPOINT(int argc, char *argv[]);
+
+const struct userspace_s userspace __attribute__ ((section (".userspace"))) =
+{
+  /* General memory map */
+
+  .us_entrypoint    = (main_t)CONFIG_USER_ENTRYPOINT,
+  .us_textstart     = (uintptr_t)&_stext,
+  .us_textend       = (uintptr_t)&_etext,
+  .us_datasource    = (uintptr_t)&_eronly,
+  .us_datastart     = (uintptr_t)&_sdata,
+  .us_dataend       = (uintptr_t)&_edata,
+  .us_bssstart      = (uintptr_t)&_sbss,
+  .us_bssend        = (uintptr_t)&_ebss,
+
+  /* Memory manager heap structure */
+
+  .us_heap          = &g_mmheap,
+
+  /* Task/thread startup routines */
+
+  .task_startup     = task_startup,
+#ifndef CONFIG_DISABLE_PTHREAD
+  .pthread_startup  = pthread_startup,
+#endif
+
+  /* Signal handler trampoline */
+
+  .signal_handler   = up_signal_handler,
+
+  /* User-space work queue support (declared in include/nuttx/wqueue.h) */
+
+#ifdef CONFIG_LIB_USRWORK
+  .work_usrstart    = work_usrstart,
+#endif
+};
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+#endif /* CONFIG_BUILD_PROTECTED && !__KERNEL__ */
diff --git a/configs/stm32l4r9ai-disco/knsh/Make.defs b/configs/stm32l4r9ai-disco/knsh/Make.defs
new file mode 100644
index 00000000000..f586181e7aa
--- /dev/null
+++ b/configs/stm32l4r9ai-disco/knsh/Make.defs
@@ -0,0 +1,119 @@
+############################################################################
+# configs/stm32l4r9ai-disco/knsh/Make.defs
+#
+#   Copyright (C) 2017 Gregory Nutt. All rights reserved.
+#   Author: Gregory Nutt <gnutt@nuttx.org>
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in
+#    the documentation and/or other materials provided with the
+#    distribution.
+# 3. Neither the name NuttX nor the names of its contributors may be
+#    used to endorse or promote products derived from this software
+#    without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+# COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+# OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+# POSSIBILITY OF SUCH DAMAGE.
+#
+############################################################################
+
+include ${TOPDIR}/.config
+include ${TOPDIR}/tools/Config.mk
+include ${TOPDIR}/arch/arm/src/armv7-m/Toolchain.defs
+
+LDSCRIPT1 = memory.ld
+LDSCRIPT2 = kernel-space.ld
+
+ifeq ($(WINTOOL),y)
+  # Windows-native toolchains
+  DIRLINK = $(TOPDIR)/tools/copydir.sh
+  DIRUNLINK = $(TOPDIR)/tools/unlink.sh
+  MKDEP = $(TOPDIR)/tools/mknulldeps.sh
+  ARCHINCLUDES = -I. -isystem "${shell cygpath -w $(TOPDIR)/include}"
+  ARCHXXINCLUDES = -I. -isystem "${shell cygpath -w $(TOPDIR)/include}" -isystem "${shell cygpath -w $(TOPDIR)/include/cxx}"
+  ARCHSCRIPT = -T "${shell cygpath -w $(TOPDIR)/configs/$(CONFIG_ARCH_BOARD)/scripts/$(LDSCRIPT1)}"
+  ARCHSCRIPT += -T "${shell cygpath -w $(TOPDIR)/configs/$(CONFIG_ARCH_BOARD)/scripts/$(LDSCRIPT2)}"
+else
+  # Linux/Cygwin-native toolchain
+  MKDEP = $(TOPDIR)/tools/mkdeps$(HOSTEXEEXT)
+  ARCHINCLUDES = -I. -isystem $(TOPDIR)/include
+  ARCHXXINCLUDES = -I. -isystem $(TOPDIR)/include -isystem $(TOPDIR)/include/cxx
+  ARCHSCRIPT = -T$(TOPDIR)/configs/$(CONFIG_ARCH_BOARD)/scripts/$(LDSCRIPT1)
+  ARCHSCRIPT += -T$(TOPDIR)/configs/$(CONFIG_ARCH_BOARD)/scripts/$(LDSCRIPT2)
+endif
+
+CC = $(CROSSDEV)gcc
+CXX = $(CROSSDEV)g++
+CPP = $(CROSSDEV)gcc -E
+LD = $(CROSSDEV)ld
+STRIP = $(CROSSDEV)strip --strip-unneeded
+AR = $(ARCROSSDEV)ar rcs
+NM = $(ARCROSSDEV)nm
+OBJCOPY = $(CROSSDEV)objcopy
+OBJDUMP = $(CROSSDEV)objdump
+
+ARCHCCVERSION = ${shell $(CC) -v 2>&1 | sed -n '/^gcc version/p' | sed -e 's/^gcc version \([0-9\.]\)/\1/g' -e 's/[-\ ].*//g' -e '1q'}
+ARCHCCMAJOR = ${shell echo $(ARCHCCVERSION) | cut -d'.' -f1}
+
+ifeq ($(CONFIG_DEBUG_SYMBOLS),y)
+  ARCHOPTIMIZATION = -g
+endif
+
+ifneq ($(CONFIG_DEBUG_NOOPT),y)
+  ARCHOPTIMIZATION += $(MAXOPTIMIZATION) -fno-strict-aliasing -fno-strength-reduce -fomit-frame-pointer
+endif
+
+ARCHCFLAGS = -fno-builtin
+ARCHCXXFLAGS = -fno-builtin -fno-exceptions -fcheck-new -fno-rtti
+ARCHWARNINGS = -Wall -Wstrict-prototypes -Wshadow -Wundef
+ARCHWARNINGSXX = -Wall -Wshadow -Wundef
+ARCHDEFINES =
+ARCHPICFLAGS = -fpic -msingle-pic-base -mpic-register=r10
+
+CFLAGS = $(ARCHCFLAGS) $(ARCHWARNINGS) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES) -pipe
+CPICFLAGS = $(ARCHPICFLAGS) $(CFLAGS)
+CXXFLAGS = $(ARCHCXXFLAGS) $(ARCHWARNINGSXX) $(ARCHOPTIMIZATION) $(ARCHCPUFLAGS) $(ARCHXXINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES) -pipe
+CXXPICFLAGS = $(ARCHPICFLAGS) $(CXXFLAGS)
+CPPFLAGS = $(ARCHINCLUDES) $(ARCHDEFINES) $(EXTRADEFINES)
+AFLAGS = $(CFLAGS) -D__ASSEMBLY__
+
+NXFLATLDFLAGS1 = -r -d -warn-common
+NXFLATLDFLAGS2 = $(NXFLATLDFLAGS1) -T$(TOPDIR)/binfmt/libnxflat/gnu-nxflat-pcrel.ld -no-check-sections
+LDNXFLATFLAGS = -e main -s 2048
+
+ASMEXT = .S
+OBJEXT = .o
+LIBEXT = .a
+EXEEXT =
+
+ifneq ($(CROSSDEV),arm-nuttx-elf-)
+  LDFLAGS += -nostartfiles -nodefaultlibs
+endif
+ifeq ($(CONFIG_DEBUG_SYMBOLS),y)
+  LDFLAGS += -g
+endif
+
+#LDFLAGS += -Map=${TOPDIR}/nuttx.map
+#CFLAGS += -Wa,-adhln
+#CXXFLAGS += -Wa,-adhln
+
+HOSTCC = gcc
+HOSTINCLUDES = -I.
+HOSTCFLAGS = -Wall -Wstrict-prototypes -Wshadow -Wundef -g -pipe
+HOSTLDFLAGS =
diff --git a/configs/stm32l4r9ai-disco/knsh/defconfig b/configs/stm32l4r9ai-disco/knsh/defconfig
new file mode 100644
index 00000000000..1bb7c379706
--- /dev/null
+++ b/configs/stm32l4r9ai-disco/knsh/defconfig
@@ -0,0 +1,88 @@
+#
+# This file is autogenerated: PLEASE DO NOT EDIT IT.
+#
+# You can use "make menuconfig" to make any modifications to the installed .config file.
+# You can then do "make savedefconfig" to generate a new defconfig file that includes your
+# modifications.
+#
+# CONFIG_ARCH_FPU is not set
+# CONFIG_NSH_ARGCAT is not set
+# CONFIG_NSH_CMDPARMS is not set
+CONFIG_ARCH="arm"
+CONFIG_ARCH_BOARD="stm32l4r9ai-disco"
+CONFIG_ARCH_BOARD_STM32L4R9AI_DISCO=y
+CONFIG_ARCH_BUTTONS=y
+CONFIG_ARCH_CHIP_STM32L4=y
+CONFIG_ARCH_CHIP_STM32L4R9AI=y
+CONFIG_ARCH_INTERRUPTSTACK=2048
+CONFIG_ARCH_IRQBUTTONS=y
+CONFIG_ARCH_STACKDUMP=y
+CONFIG_ARM_MPU=y
+CONFIG_BOARDCTL_IOCTL=y
+CONFIG_BOARDCTL_UNIQUEID=y
+CONFIG_BOARDCTL_UNIQUEID_SIZE=12
+CONFIG_BOARD_LOOPSPERMSEC=9234
+CONFIG_BUILD_PROTECTED=y
+CONFIG_DEBUG_FULLOPT=y
+CONFIG_DEBUG_SYMBOLS=y
+CONFIG_DEV_LOOP=y
+CONFIG_DEV_ZERO=y
+CONFIG_FS_PROCFS=y
+CONFIG_FS_PROCFS_REGISTER=y
+CONFIG_FS_TMPFS=y
+CONFIG_HAVE_CXX=y
+CONFIG_HAVE_CXXINITIALIZE=y
+CONFIG_I2C=y
+CONFIG_I2C_DRIVER=y
+CONFIG_INTELHEX_BINARY=y
+CONFIG_MAX_TASKS=16
+CONFIG_MAX_WDOGPARMS=2
+CONFIG_MM_REGIONS=3
+CONFIG_MTD=y
+CONFIG_MTD_PARTITION=y
+CONFIG_NFILE_DESCRIPTORS=8
+CONFIG_NFILE_STREAMS=8
+CONFIG_NSH_ARCHINIT=y
+CONFIG_NSH_DISABLE_DD=y
+CONFIG_NSH_DISABLE_IFUPDOWN=y
+CONFIG_NSH_DISABLE_MKRD=y
+CONFIG_NSH_FILEIOSIZE=512
+CONFIG_NSH_READLINE=y
+CONFIG_NUTTX_USERSPACE=0x08020000
+CONFIG_PASS1_BUILDIR="configs/stm32l4r9ai-disco/kernel"
+CONFIG_PREALLOC_MQ_MSGS=4
+CONFIG_PREALLOC_TIMERS=4
+CONFIG_PREALLOC_WDOGS=8
+CONFIG_RAM_SIZE=98304
+CONFIG_RAM_START=0x20000000
+CONFIG_RAW_BINARY=y
+CONFIG_RR_INTERVAL=200
+CONFIG_RTC_ALARM=y
+CONFIG_RTC_DATETIME=y
+CONFIG_RTC_DRIVER=y
+CONFIG_RTC_IOCTL=y
+CONFIG_RTC_NALARMS=2
+CONFIG_SCHED_WAITPID=y
+CONFIG_SDCLONE_DISABLE=y
+CONFIG_SPI_DRIVER=y
+CONFIG_STM32L4_DISABLE_IDLE_SLEEP_DURING_DEBUG=y
+CONFIG_STM32L4_I2C1=y
+CONFIG_STM32L4_I2C3=y
+CONFIG_STM32L4_PWR=y
+CONFIG_STM32L4_RNG=y
+CONFIG_STM32L4_RTC=y
+CONFIG_STM32L4_SAI1PLL=y
+CONFIG_STM32L4_SPI2=y
+CONFIG_STM32L4_SRAM2_HEAP=y
+CONFIG_STM32L4_UART4=y
+CONFIG_STM32L4_USART2=y
+CONFIG_SYSTEM_NSH=y
+CONFIG_SYSTEM_NSH_CXXINITIALIZE=y
+CONFIG_SYS_RESERVED=8
+CONFIG_TASK_NAME_SIZE=0
+CONFIG_UART4_BAUD=2000000
+CONFIG_UART4_RXBUFSIZE=512
+CONFIG_UART4_SERIAL_CONSOLE=y
+CONFIG_USERMAIN_STACKSIZE=3072
+CONFIG_USER_ENTRYPOINT="nsh_main"
+CONFIG_WDOG_INTRESERVE=1
diff --git a/configs/stm32l4r9ai-disco/nsh/defconfig b/configs/stm32l4r9ai-disco/nsh/defconfig
index 7d3a4e0cf02..8c551c0e259 100644
--- a/configs/stm32l4r9ai-disco/nsh/defconfig
+++ b/configs/stm32l4r9ai-disco/nsh/defconfig
@@ -7,7 +7,6 @@
 #
 # CONFIG_ARCH_FPU is not set
 # CONFIG_NSH_ARGCAT is not set
-# CONFIG_NSH_CMDOPT_HEXDUMP is not set
 # CONFIG_NSH_CMDPARMS is not set
 CONFIG_ARCH="arm"
 CONFIG_ARCH_BOARD="stm32l4r9ai-disco"
@@ -27,12 +26,15 @@ CONFIG_DEV_LOOP=y
 CONFIG_DEV_ZERO=y
 CONFIG_EXAMPLES_ALARM=y
 CONFIG_EXAMPLES_MEDIA=y
+CONFIG_EXAMPLES_RANDOM=y
 CONFIG_FS_PROCFS=y
 CONFIG_FS_PROCFS_REGISTER=y
 CONFIG_FS_ROMFS=y
 CONFIG_FS_TMPFS=y
 CONFIG_HAVE_CXX=y
 CONFIG_HAVE_CXXINITIALIZE=y
+CONFIG_I2C=y
+CONFIG_I2C_DRIVER=y
 CONFIG_INTELHEX_BINARY=y
 CONFIG_MAX_TASKS=16
 CONFIG_MAX_WDOGPARMS=2
@@ -46,7 +48,6 @@ CONFIG_NSH_ARCHROMFS=y
 CONFIG_NSH_BUILTIN_APPS=y
 CONFIG_NSH_DISABLE_IFUPDOWN=y
 CONFIG_NSH_FILEIOSIZE=512
-CONFIG_NSH_LINELEN=80
 CONFIG_NSH_READLINE=y
 CONFIG_NSH_ROMFSETC=y
 CONFIG_PREALLOC_MQ_MSGS=4
@@ -63,12 +64,15 @@ CONFIG_RTC_IOCTL=y
 CONFIG_RTC_NALARMS=2
 CONFIG_SCHED_WAITPID=y
 CONFIG_SDCLONE_DISABLE=y
-CONFIG_SPI=y
+CONFIG_SPI_DRIVER=y
 CONFIG_STM32L4_DISABLE_IDLE_SLEEP_DURING_DEBUG=y
+CONFIG_STM32L4_I2C1=y
+CONFIG_STM32L4_I2C3=y
 CONFIG_STM32L4_PWR=y
 CONFIG_STM32L4_RNG=y
 CONFIG_STM32L4_RTC=y
 CONFIG_STM32L4_SAI1PLL=y
+CONFIG_STM32L4_SPI2=y
 CONFIG_STM32L4_SRAM2_HEAP=y
 CONFIG_STM32L4_UART4=y
 CONFIG_STM32L4_USART2=y
diff --git a/configs/stm32l4r9ai-disco/scripts/memory.ld b/configs/stm32l4r9ai-disco/scripts/memory.ld
index 3351176ff11..18904dc888f 100644
--- a/configs/stm32l4r9ai-disco/scripts/memory.ld
+++ b/configs/stm32l4r9ai-disco/scripts/memory.ld
@@ -46,16 +46,16 @@
  * 0x0800:0000 address range.
  *
  * For MPU support, the kernel-mode NuttX section is assumed to be 128Kb of
- * FLASH and 4Kb of SRAM.  That is an excessive amount for the kernel which
+ * FLASH and 16Kb of SRAM.  That is an excessive amount for the kernel which
  * should fit into 64KB and, of course, can be optimized as needed (See
- * also configs/stm32f4discovery/scripts/kernel-space.ld).  Allowing the
+ * also configs/stm32l4r9ai-disco/scripts/kernel-space.ld).  Allowing the
  * additional does permit addition debug instrumentation to be added to the
  * kernel space without overflowing the partition.
  *
  * Alignment of the user space FLASH partition is also a critical factor:
  * The user space FLASH partition will be spanned with a single region of
  * size 2**n bytes.  The alignment of the user-space region must be the same.
- * As a consequence, as the user-space increases in size, the alignmment
+ * As a consequence, as the user-space increases in size, the alignment
  * requirement also increases.
  *
  * This alignment requirement means that the largest user space FLASH region
@@ -63,39 +63,21 @@
  * 0x08800000.  If you change this address, don't forget to change the
  * CONFIG_NUTTX_USERSPACE configuration setting to match and to modify
  * the check in kernel/userspace.c.
- *
- * For the same reasons, the maximum size of the SRAM mapping is limited to
- * 4KB.  Both of these alignment limitations could be reduced by using
- * multiple regions to map the FLASH/SDRAM range or perhaps with some
- * clever use of subregions.
- *
- * A detailed memory map for the 96KB SRAM region is as follows:
- *
- *   0x20000 0000:  Kernel .data region.  Typical size: 0.1KB
- *   ------- ----   Kernel .bss  region.  Typical size: 1.8KB
- *   0x20000 0800:  Kernel IDLE thread stack (approximate).  Size is
- *                  determined by CONFIG_IDLETHREAD_STACKSIZE and
- *                  adjustments for alignment.  Typical is 1KB.
- *   ------- ----   Padded to 4KB
- *   0x20000 2000:  User .data region.  Size is variable.
- *   ------- ----   User .bss region  Size is variable.
- *   0x20000 4000:  Beginning of kernel heap.  Size determined by
- *                  CONFIG_MM_KERNEL_HEAPSIZE.
- *   ------- ----   Beginning of user heap.  Can vary with other settings.
- *   0x20001 8000:  End+1 of CPU RAM
  */
 
 MEMORY
 {
-    /* 1024Kb FLASH */
+    /* 2048Kb FLASH */
 
     kflash (rx)      : ORIGIN = 0x08000000, LENGTH = 128K
     uflash (rx)      : ORIGIN = 0x08020000, LENGTH = 128K
-    xflash (rx)      : ORIGIN = 0x08040000, LENGTH = 768K
+    xflash (rx)      : ORIGIN = 0x08040000, LENGTH = 1792K
 
-    /* 96Kb of contiguous SRAM */
+    /* 640Kb of contiguous SRAM */
 
-    ksram (rwx)      : ORIGIN = 0x20000000, LENGTH = 8K
-    usram (rwx)      : ORIGIN = 0x20001000, LENGTH = 8K
-    xsram (rwx)      : ORIGIN = 0x20002000, LENGTH = 80K
+    ksram (rwx)      : ORIGIN = 0x20000000, LENGTH = 16K
+    usram (rwx)      : ORIGIN = 0x20004000, LENGTH = 16K
+    xsram (rwx)      : ORIGIN = 0x20008000, LENGTH = 192K + 64K - 32K
+
+    sram3 (rwx)      : ORIGIN = 0x20040000, LENGTH = 384K
 }
diff --git a/configs/stm32l4r9ai-disco/src/Makefile b/configs/stm32l4r9ai-disco/src/Makefile
index 8828e6e117f..a809ba6ee01 100644
--- a/configs/stm32l4r9ai-disco/src/Makefile
+++ b/configs/stm32l4r9ai-disco/src/Makefile
@@ -36,16 +36,12 @@
 -include $(TOPDIR)/Make.defs
 
 ASRCS =
-CSRCS = stm32_boot.c stm32_spi.c
+CSRCS = stm32_boot.c
 
 ifeq ($(CONFIG_ARCH_BOARD_STM32L4_CUSTOM_CLOCKCONFIG),y)
 CSRCS += stm32_clockconfig.c
 endif
 
-ifeq ($(CONFIG_STM32L4_OTGFS),y)
-CSRCS += stm32_usb.c
-endif
-
 ifeq ($(CONFIG_ARCH_LEDS),y)
 CSRCS += stm32_autoleds.c
 else
@@ -57,13 +53,26 @@ CSRCS += stm32_buttons.c
 endif
 
 ifeq ($(CONFIG_ADC),y)
+ifeq ($(CONFIG_STM32L4_ADC),y)
 CSRCS += stm32_adc.c
 endif
+ifeq ($(CONFIG_STM32L4_DFSDM),y)
+CSRCS += stm32_dfsdm.c
+endif
+endif
 
 ifeq ($(CONFIG_DAC),y)
 CSRCS += stm32_dac.c
 endif
 
+ifeq ($(CONFIG_STM32L4_SPI),y)
+CSRCS += stm32_spi.c
+endif
+
+ifeq ($(CONFIG_STM32L4_OTGFS),y)
+CSRCS += stm32_usb.c
+endif
+
 ifeq ($(CONFIG_LIB_BOARDCTL),y)
 CSRCS += stm32_appinit.c
 endif
diff --git a/configs/stm32l4r9ai-disco/src/stm32_appinit.c b/configs/stm32l4r9ai-disco/src/stm32_appinit.c
index 8feee3384c8..d84f09fbe7b 100644
--- a/configs/stm32l4r9ai-disco/src/stm32_appinit.c
+++ b/configs/stm32l4r9ai-disco/src/stm32_appinit.c
@@ -78,6 +78,15 @@
  * Private Data
  ****************************************************************************/
 
+#ifdef CONFIG_I2C
+#  ifdef CONFIG_STM32L4_I2C1
+static struct i2c_master_s* g_i2c1;
+#  endif
+#  ifdef CONFIG_STM32L4_I2C3
+static struct i2c_master_s* g_i2c3;
+#  endif
+#endif
+
 /****************************************************************************
  * Public Functions
  ****************************************************************************/
@@ -156,6 +165,23 @@ int board_app_initialize(uintptr_t arg)
     }
 #endif
 
+#ifdef CONFIG_I2C
+  i2cinfo("Initializing I2C buses\n");
+#ifdef CONFIG_STM32L4_I2C1
+  g_i2c1 = stm32l4_i2cbus_initialize(1);
+#ifdef CONFIG_I2C_DRIVER
+  i2c_register(g_i2c1, 1);
+#endif
+#endif
+
+#ifdef CONFIG_STM32L4_I2C3
+  g_i2c3 = stm32l4_i2cbus_initialize(3);
+#ifdef CONFIG_I2C_DRIVER
+  i2c_register(g_i2c3, 3);
+#endif
+#endif
+#endif /* CONFIG_I2C */
+
 #ifdef HAVE_USBHOST
   /* Initialize USB host operation.  stm32l4_usbhost_initialize() starts a
    * thread that will monitor for USB connection and disconnection events.
@@ -184,7 +210,16 @@ int board_app_initialize(uintptr_t arg)
   ainfo("Initializing ADC\n");
 
   (void)stm32l4_adc_setup();
+#ifdef CONFIG_STM32L4_DFSDM
+  /* Initialize DFSDM and register its filters as additional ADC devices. */
+
+  ret = stm32_dfsdm_setup();
+  if (ret < 0)
+    {
+      aerr("ERROR: Failed to start DFSDM: %d\n", ret);
+    }
 #endif
+#endif /* CONFIG_ADC */
 
 #ifdef CONFIG_DAC
   ainfo("Initializing DAC\n");
diff --git a/configs/stm32l4r9ai-disco/src/stm32_boot.c b/configs/stm32l4r9ai-disco/src/stm32_boot.c
index 4a573add40a..125a8c68bd1 100644
--- a/configs/stm32l4r9ai-disco/src/stm32_boot.c
+++ b/configs/stm32l4r9ai-disco/src/stm32_boot.c
@@ -73,8 +73,8 @@ void stm32l4_board_initialize(void)
    * stm32_spiinitialize() has been brought into the link.
    */
 
-#if defined(CONFIG_STM32_SPI1) || defined(CONFIG_STM32_SPI2) || defined(CONFIG_STM32_SPI3)
-  stm32l4_spiinitialize();
+#ifdef CONFIG_STM32L4_SPI
+  stm32_spiinitialize();
 #endif
 
 #ifdef CONFIG_STM32L4_OTGFS
diff --git a/configs/stm32l4r9ai-disco/src/stm32_dfsdm.c b/configs/stm32l4r9ai-disco/src/stm32_dfsdm.c
new file mode 100644
index 00000000000..ab381fa810c
--- /dev/null
+++ b/configs/stm32l4r9ai-disco/src/stm32_dfsdm.c
@@ -0,0 +1,146 @@
+/****************************************************************************
+ * configs/stm32l4r9ai-disco/src/stm32_dfsdm.c
+ *
+ *   Copyright (C) 2019 Haltian Ltd. All rights reserved.
+ *   Authors: Juha Niskanen <juha.niskanen@haltian.com>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <errno.h>
+#include <debug.h>
+
+#include <nuttx/board.h>
+#include <nuttx/analog/adc.h>
+
+#include "stm32l4_gpio.h"
+#include "stm32l4_dfsdm.h"
+#include "stm32l4r9ai-disco.h"
+
+#include <arch/board/board.h>
+
+#if defined(CONFIG_ADC) && defined(CONFIG_STM32L4_DFSDM)
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: stm32_dfsdm_setup
+ ****************************************************************************/
+
+int stm32_dfsdm_setup(void)
+{
+  static bool initialized = false;
+
+  if (!initialized)
+    {
+      int ret;
+      struct adc_dev_s *adc;
+
+      ainfo("Initializing DFSDM\n");
+
+      /* TODO: just some arbitrary channels selected, missing input pin
+       * configuration and DFSDM mode selection: SPI/Manchester or internal
+       * parallel inputs (CPU/DMA/ADC).
+       */
+
+#ifdef CONFIG_STM32L4_DFSDM1_FLT0
+      adc = stm32l4_dfsdm_initialize(0, (const uint8_t[1]){0}, 1);
+      if (adc == NULL)
+        {
+          aerr("Failed to get DFSDM FLT0 interface\n");
+          return -ENODEV;
+        }
+
+      ret = adc_register("/dev/adc_flt0", adc);
+      if (ret < 0)
+        {
+          aerr("adc_register failed: %d\n", ret);
+          return ret;
+        }
+#endif
+#ifdef CONFIG_STM32L4_DFSDM1_FLT1
+      adc = stm32l4_dfsdm_initialize(1, (const uint8_t[2]){0,1}, 2);
+      if (adc == NULL)
+        {
+          aerr("Failed to get DFSDM FLT1 interface\n");
+          return -ENODEV;
+        }
+
+      ret = adc_register("/dev/adc_flt1", adc);
+      if (ret < 0)
+        {
+          aerr("adc_register failed: %d\n", ret);
+          return ret;
+        }
+#endif
+#ifdef CONFIG_STM32L4_DFSDM1_FLT2
+      adc = stm32l4_dfsdm_initialize(2, (const uint8_t[8]){0,1,2,3,4,5,6,7}, 8);
+      if (adc == NULL)
+        {
+          aerr("Failed to get DFSDM FLT2 interface\n");
+          return -ENODEV;
+        }
+
+      ret = adc_register("/dev/adc_flt2", adc);
+      if (ret < 0)
+        {
+          aerr("adc_register failed: %d\n", ret);
+          return ret;
+        }
+#endif
+#ifdef CONFIG_STM32L4_DFSDM1_FLT3
+      adc = stm32l4_dfsdm_initialize(3, (const uint8_t[4]){6,5,4,3}, 4);
+      if (adc == NULL)
+        {
+          aerr("Failed to get DFSDM FLT3 interface\n");
+          return -ENODEV;
+        }
+
+      ret = adc_register("/dev/adc_flt3", adc);
+      if (ret < 0)
+        {
+          aerr("adc_register failed: %d\n", ret);
+          return ret;
+        }
+#endif
+
+      initialized = true;
+    }
+
+  return OK;
+}
+#endif /* CONFIG_ADC && CONFIG_STM32L4_DFSDM */
diff --git a/configs/stm32l4r9ai-disco/src/stm32_spi.c b/configs/stm32l4r9ai-disco/src/stm32_spi.c
index b57b9cc71d5..dbf3720c01c 100644
--- a/configs/stm32l4r9ai-disco/src/stm32_spi.c
+++ b/configs/stm32l4r9ai-disco/src/stm32_spi.c
@@ -45,6 +45,7 @@
 #include <errno.h>
 
 #include <nuttx/spi/spi.h>
+#include <nuttx/spi/spi_transfer.h>
 #include <arch/board/board.h>
 
 #include <up_arch.h>
@@ -53,20 +54,20 @@
 
 #include "stm32l4r9ai-disco.h"
 
-#if defined(CONFIG_STM32_SPI1) || defined(CONFIG_STM32_SPI2) || defined(CONFIG_STM32_SPI3)
+#if defined(CONFIG_STM32L4_SPI1) || defined(CONFIG_STM32L4_SPI2) || defined(CONFIG_STM32L4_SPI3)
 
 /************************************************************************************
  * Public Data
  ************************************************************************************/
 /* Global driver instances */
 
-#ifdef CONFIG_STM32_SPI1
+#ifdef CONFIG_STM32L4_SPI1
 struct spi_dev_s *g_spi1;
 #endif
-#ifdef CONFIG_STM32_SPI2
+#ifdef CONFIG_STM32L4_SPI2
 struct spi_dev_s *g_spi2;
 #endif
-#ifdef CONFIG_STM32_SPI3
+#ifdef CONFIG_STM32L4_SPI3
 struct spi_dev_s *g_spi3;
 #endif
 
@@ -84,53 +85,62 @@ struct spi_dev_s *g_spi3;
 
 void weak_function stm32_spiinitialize(void)
 {
-#ifdef CONFIG_STM32_SPI1
+#ifdef CONFIG_STM32L4_SPI1
   /* Configure SPI-based devices on SPI1 */
 
-  g_spi1 = up_spiinitialize(1);
+  g_spi1 = stm32l4_spibus_initialize(1);
   if (!g_spi1)
     {
       spierr("ERROR: [boot] FAILED to initialize SPI port 1\n");
     }
+#ifdef CONFIG_SPI_DRIVER
+  spi_register(g_spi1, 1);
+#endif
 
 #ifdef HAVE_MMCSD
-  stm32_configgpio(GPIO_SPI_CS_SD_CARD);
+  stm32l4_configgpio(GPIO_SPI_CS_SD_CARD);
 #endif
 #endif
 
-#ifdef CONFIG_STM32_SPI2
+#ifdef CONFIG_STM32L4_SPI2
   /* Configure SPI-based devices on SPI2 */
 
-  g_spi2 = up_spiinitialize(2);
+  g_spi2 = stm32l4_spibus_initialize(2);
   if (!g_spi2)
     {
       spierr("ERROR: [boot] FAILED to initialize SPI port 2\n");
     }
+#ifdef CONFIG_SPI_DRIVER
+  spi_register(g_spi2, 2);
+#endif
 
 #warning No devices specified on SPI2
 #endif
 
-#ifdef CONFIG_STM32_SPI2
+#ifdef CONFIG_STM32L4_SPI3
   /* Configure SPI-based devices on SPI3 */
 
-  g_spi2 = up_spiinitialize(3);
-  if (!g_spi2)
+  g_spi3 = stm32l4_spibus_initialize(3);
+  if (!g_spi3)
     {
       spierr("ERROR: [boot] FAILED to initialize SPI port 3\n");
     }
+#ifdef CONFIG_SPI_DRIVER
+  spi_register(g_spi3, 3);
+#endif
 
 #warning No devices specified on SPI3
 #endif
 }
 
 /****************************************************************************
- * Name:  stm32_spi1/2/3select and stm32_spi1/2/3status
+ * Name:  stm32l4_spi1/2/3select and stm32l4_spi1/2/3status
  *
  * Description:
  *   The external functions, stm32_spi1/2/3select and stm32_spi1/2/3status must be
  *   provided by board-specific logic.  They are implementations of the select
  *   and status methods of the SPI interface defined by struct spi_ops_s (see
- *   include/nuttx/spi/spi.h). All other methods (including up_spiinitialize())
+ *   include/nuttx/spi/spi.h). All other methods (including stm32l4_spibus_initialize())
  *   are provided by common STM32 logic.  To use this common SPI logic on your
  *   board:
  *
@@ -139,60 +149,60 @@ void weak_function stm32_spiinitialize(void)
  *   2. Provide stm32_spi1/2/3select() and stm32_spi1/2/3status() functions in your
  *      board-specific logic.  These functions will perform chip selection and
  *      status operations using GPIOs in the way your board is configured.
- *   3. Add a calls to up_spiinitialize() in your low level application
+ *   3. Add a calls to stm32l4_spibus_initialize() in your low level application
  *      initialization logic
- *   4. The handle returned by up_spiinitialize() may then be used to bind the
+ *   4. The handle returned by stm32l4_spibus_initialize() may then be used to bind the
  *      SPI driver to higher level logic (e.g., calling
  *      mmcsd_spislotinitialize(), for example, will bind the SPI driver to
  *      the SPI MMC/SD driver).
  *
  ****************************************************************************/
 
-#ifdef CONFIG_STM32_SPI1
-void stm32_spi1select(FAR struct spi_dev_s *dev, uint32_t devid, bool selected)
+#ifdef CONFIG_STM32L4_SPI1
+void stm32l4_spi1select(FAR struct spi_dev_s *dev, uint32_t devid, bool selected)
 {
   spiinfo("devid: %d CS: %s\n", (int)devid, selected ? "assert" : "de-assert");
 
 #ifdef HAVE_MMCSD
   if (devid == SPIDEV_MMCSD(0))
     {
-      stm32_gpiowrite(GPIO_SPI_CS_SD_CARD, !selected);
+      stm32l4_gpiowrite(GPIO_SPI_CS_SD_CARD, !selected);
     }
 #endif
 }
 
-uint8_t stm32_spi1status(FAR struct spi_dev_s *dev, uint32_t devid)
+uint8_t stm32l4_spi1status(FAR struct spi_dev_s *dev, uint32_t devid)
 {
   return 0;
 }
 #endif
 
-#ifdef CONFIG_STM32_SPI2
-void stm32_spi2select(FAR struct spi_dev_s *dev, uint32_t devid, bool selected)
+#ifdef CONFIG_STM32L4_SPI2
+void stm32l4_spi2select(FAR struct spi_dev_s *dev, uint32_t devid, bool selected)
 {
   spiinfo("devid: %d CS: %s\n", (int)devid, selected ? "assert" : "de-assert");
 }
 
-uint8_t stm32_spi2status(FAR struct spi_dev_s *dev, uint32_t devid)
+uint8_t stm32l4_spi2status(FAR struct spi_dev_s *dev, uint32_t devid)
 {
   return 0;
 }
 #endif
 
-#ifdef CONFIG_STM32_SPI3
-void stm32_spi3select(FAR struct spi_dev_s *dev, uint32_t devid, bool selected)
+#ifdef CONFIG_STM32L4_SPI3
+void stm32l4_spi3select(FAR struct spi_dev_s *dev, uint32_t devid, bool selected)
 
   spiinfo("devid: %d CS: %s\n", (int)devid, selected ? "assert" : "de-assert");
 }
 
-uint8_t stm32_spi3status(FAR struct spi_dev_s *dev, uint32_t devid)
+uint8_t stm32l4_spi3status(FAR struct spi_dev_s *dev, uint32_t devid)
 {
   return 0;
 }
 #endif
 
 /****************************************************************************
- * Name: stm32_spi1cmddata
+ * Name: stm32l4_spi1/2/3cmddata
  *
  * Description:
  *   Set or clear the SH1101A A0 or SD1306 D/C n bit to select data (true)
@@ -215,26 +225,26 @@ uint8_t stm32_spi3status(FAR struct spi_dev_s *dev, uint32_t devid)
  ****************************************************************************/
 
 #ifdef CONFIG_SPI_CMDDATA
-#ifdef CONFIG_STM32_SPI1
-int stm32_spi1cmddata(FAR struct spi_dev_s *dev, uint32_t devid, bool cmd)
+#ifdef CONFIG_STM32L4_SPI1
+int stm32l4_spi1cmddata(FAR struct spi_dev_s *dev, uint32_t devid, bool cmd)
 {
   return OK;
 }
 #endif
 
-#ifdef CONFIG_STM32_SPI2
-int stm32_spi2cmddata(FAR struct spi_dev_s *dev, uint32_t devid, bool cmd)
+#ifdef CONFIG_STM32L4_SPI2
+int stm32l4_spi2cmddata(FAR struct spi_dev_s *dev, uint32_t devid, bool cmd)
 {
   return OK;
 }
 #endif
 
-#ifdef CONFIG_STM32_SPI3
-int stm32_spi3cmddata(FAR struct spi_dev_s *dev, uint32_t devid, bool cmd)
+#ifdef CONFIG_STM32L4_SPI3
+int stm32l4_spi3cmddata(FAR struct spi_dev_s *dev, uint32_t devid, bool cmd)
 {
   return OK;
 }
 #endif
 #endif /* CONFIG_SPI_CMDDATA */
 
-#endif /* CONFIG_STM32_SPI1 || CONFIG_STM32_SPI2 || CONFIG_STM32_SPI3 */
+#endif /* CONFIG_STM32L4_SPI1 || CONFIG_STM32L4_SPI2 || CONFIG_STM32L4_SPI3 */
diff --git a/configs/stm32l4r9ai-disco/src/stm32l4r9ai-disco.h b/configs/stm32l4r9ai-disco/src/stm32l4r9ai-disco.h
index 20ab622e0cb..1d9dec3d2a1 100644
--- a/configs/stm32l4r9ai-disco/src/stm32l4r9ai-disco.h
+++ b/configs/stm32l4r9ai-disco/src/stm32l4r9ai-disco.h
@@ -190,10 +190,10 @@
 
 /* Global driver instances */
 
-#ifdef CONFIG_STM32_SPI1
+#ifdef CONFIG_STM32L4_SPI1
 extern struct spi_dev_s *g_spi1;
 #endif
-#ifdef CONFIG_STM32_SPI2
+#ifdef CONFIG_STM32L4_SPI2
 extern struct spi_dev_s *g_spi2;
 #endif
 
@@ -231,6 +231,18 @@ int stm32l4_adc_measure_voltages(uint32_t *vrefint, uint32_t *vbat, uint32_t *ve
 
 int stm32l4_dac_setup(void);
 
+/************************************************************************************
+ * Name: stm32_dfsdm_setup
+ *
+ * Description:
+ *   Initialize DFSDM and register the ADC drivers for DFSDM filters.
+ *
+ ************************************************************************************/
+
+#if defined(CONFIG_ADC) && defined(CONFIG_STM32L4_DFSDM)
+int stm32_dfsdm_setup(void);
+#endif
+
 /************************************************************************************
  * Name: stm32_spiinitialize
  *