diff --git a/bsp/stm32/stm32l475-atk-pandora/board/SConscript b/bsp/stm32/stm32l475-atk-pandora/board/SConscript
index 97c31ee844847ea92fadda573ae1ad81b9feef65..513aa8598a358f61c8f4e60ae505b0244fc8c926 100644
--- a/bsp/stm32/stm32l475-atk-pandora/board/SConscript
+++ b/bsp/stm32/stm32l475-atk-pandora/board/SConscript
@@ -47,7 +47,7 @@ if GetDepend(['BSP_USING_AUDIO']):
 
 startup_path_prefix = SDK_LIB
 
-if rtconfig.PLATFORM in ['gcc']:
+if rtconfig.PLATFORM in ['gcc', 'llvm-arm']:
     src += [startup_path_prefix + '/STM32L4xx_HAL/CMSIS/Device/ST/STM32L4xx/Source/Templates/gcc/startup_stm32l475xx.s']
 elif rtconfig.PLATFORM in ['armcc', 'armclang']:
     src += [startup_path_prefix + '/STM32L4xx_HAL/CMSIS/Device/ST/STM32L4xx/Source/Templates/arm/startup_stm32l475xx.s']
diff --git a/bsp/stm32/stm32l475-atk-pandora/rtconfig.py b/bsp/stm32/stm32l475-atk-pandora/rtconfig.py
index af29494a89cf70f0dd3bb2afd5c0f6bfdd7aa172..6b54a18e1a3f10f06131cb8700e20d26c279ec21 100644
--- a/bsp/stm32/stm32l475-atk-pandora/rtconfig.py
+++ b/bsp/stm32/stm32l475-atk-pandora/rtconfig.py
@@ -24,6 +24,9 @@ elif CROSS_TOOL == 'keil':
 elif CROSS_TOOL == 'iar':
     PLATFORM    = 'iccarm'
     EXEC_PATH   = r'C:/Program Files (x86)/IAR Systems/Embedded Workbench 8.3'
+elif CROSS_TOOL == 'llvm-arm':
+    PLATFORM    = 'llvm-arm'
+    EXEC_PATH   = r'D:\Progrem\LLVMEmbeddedToolchainForArm-16.0.0-Windows-x86_64\bin'
 
 if os.getenv('RTT_EXEC_PATH'):
     EXEC_PATH = os.getenv('RTT_EXEC_PATH')
@@ -176,6 +179,36 @@ elif PLATFORM == 'iccarm':
     
     EXEC_PATH = EXEC_PATH + '/arm/bin/'
     POST_ACTION = 'ielftool --bin $TARGET rtthread.bin'
+elif PLATFORM == 'llvm-arm':
+    # toolchains
+    PREFIX = 'llvm-'
+    CC = 'clang'
+    AS = 'clang'
+    AR = PREFIX + 'ar'
+    CXX = 'clang++'
+    LINK = 'clang'
+    TARGET_EXT = 'elf'
+    SIZE = PREFIX + 'size'
+    OBJDUMP = PREFIX + 'objdump'
+    OBJCPY = PREFIX + 'objcopy'
+    DEVICE = ' --config armv7em_hard_fpv4_sp_d16.cfg'
+    CFLAGS = DEVICE
+    CFLAGS += ' -mfloat-abi=hard -march=armv7em -mfpu=fpv4-sp-d16'
+    AFLAGS = ' -c' + DEVICE + ' -Wa,-mimplicit-it=thumb ' ## -x assembler-with-cpp
+    LFLAGS = DEVICE + ' -Wl,--gc-sections,-Map=rt-thread.map,-u,Reset_Handler -T board/linker_scripts/link.lds'
+
+    CPATH = ''
+    LPATH = ''
+
+    if BUILD == 'debug':
+        CFLAGS += ' -O0 -gdwarf-2 -g'
+        AFLAGS += ' -gdwarf-2'
+    else:
+        CFLAGS += ' -O2'
+
+    CXXFLAGS = CFLAGS 
+
+    POST_ACTION = OBJCPY + ' -O binary $TARGET rtthread.bin\n' + SIZE + ' $TARGET \n'
 
 def dist_handle(BSP_ROOT, dist_dir):
     import sys
diff --git a/components/drivers/spi/SConscript b/components/drivers/spi/SConscript
index 27b7a8dd71fed60a2d8cfa554b48ef8db340d0bb..e84ed7bb066fe57065e7308925e84dd1c5943120 100644
--- a/components/drivers/spi/SConscript
+++ b/components/drivers/spi/SConscript
@@ -29,7 +29,7 @@ if GetDepend('RT_USING_SFUD'):
     if GetDepend('RT_SFUD_USING_SFDP'):
         src_device += ['sfud/src/sfud_sfdp.c']
 
-    if rtconfig.PLATFORM in ['gcc', 'armclang']:
+    if rtconfig.PLATFORM in ['gcc', 'armclang', 'llvm-arm']:
         LOCAL_CFLAGS += ' -std=c99'
     elif rtconfig.PLATFORM in ['armcc']:
         LOCAL_CFLAGS += ' --c99'
diff --git a/components/libc/compilers/common/cstring.c b/components/libc/compilers/common/cstring.c
index 733433598e26c077aa5d81d848357f76539de30a..59c516d273e80d24b8aee4713ba841ce4261498a 100644
--- a/components/libc/compilers/common/cstring.c
+++ b/components/libc/compilers/common/cstring.c
@@ -19,10 +19,12 @@
  *
  * @note  The bzero() function is deprecated (marked as LEGACY in POSIX. 1-2001).
  */
+#ifndef RT_USING_PICOLIBC
 void bzero(void* s, size_t n)
 {
     rt_memset(s, 0, n);
 }
+#endif
 
 void bcopy(const void* src, void* dest, size_t n)
 {
diff --git a/components/libc/compilers/common/extension/SConscript b/components/libc/compilers/common/extension/SConscript
index ddd83c82345099dab6b633e5b0c4a5457cb00c04..75bb23d18e229b51d2bdd9c8d02109edec844870 100644
--- a/components/libc/compilers/common/extension/SConscript
+++ b/components/libc/compilers/common/extension/SConscript
@@ -9,7 +9,7 @@ group = []
 
 src += Glob('*.c')
 
-if rtconfig.PLATFORM != 'gcc':
+if rtconfig.PLATFORM != 'gcc' and rtconfig.PLATFORM != 'llvm-arm':
     group = DefineGroup('Compiler', src, depend = [''], CPPPATH = CPPPATH)
 
 list = os.listdir(cwd)
diff --git a/components/libc/compilers/picolibc/README.md b/components/libc/compilers/picolibc/README.md
new file mode 100644
index 0000000000000000000000000000000000000000..af766e7ca73690573f33d4caf69ab899742a464f
--- /dev/null
+++ b/components/libc/compilers/picolibc/README.md
@@ -0,0 +1,8 @@
+# PICOLIBC (LLVM-ARM) porting for RT-Thread
+
+https://github.com/ARM-software/LLVM-embedded-toolchain-for-Arm
+
+https://github.com/picolibc/picolibc
+
+
+
diff --git a/components/libc/compilers/picolibc/SConscript b/components/libc/compilers/picolibc/SConscript
new file mode 100644
index 0000000000000000000000000000000000000000..999f7cca561f6589f19f00597e4623a680771e36
--- /dev/null
+++ b/components/libc/compilers/picolibc/SConscript
@@ -0,0 +1,29 @@
+import os
+from building import *
+from llvm_arm import *
+Import('rtconfig')
+
+group = []
+
+picolibc_version = GetPicoLibcVersion(rtconfig)
+
+if picolibc_version and not GetDepend('RT_USING_EXTERNAL_LIBC'):
+    print('PicoLibc version: ' + picolibc_version)
+
+    cwd = GetCurrentDir()
+    src = Glob('*.c')
+
+    CPPPATH = [cwd]
+    CPPDEFINES = ['RT_USING_PICOLIBC', 'RT_USING_LIBC', '_POSIX_C_SOURCE=1', '__PICOLIBC_ERRNO_FUNCTION=pico_get_errno'] # identify this is Newlib, and only enable POSIX.1-1990
+    # LIBS = ['c', 'm'] # link libc and libm
+    AddDepend(['RT_USING_PICOLIBC', 'RT_USING_LIBC'])
+
+    group = group + DefineGroup('Compiler', src, depend = [''], CPPPATH = CPPPATH, CPPDEFINES = CPPDEFINES)#, LIBS = LIBS)
+
+    list = os.listdir(cwd)
+    for d in list:
+        path = os.path.join(cwd, d)
+        if os.path.isfile(os.path.join(path, 'SConscript')):
+            group = group + SConscript(os.path.join(d, 'SConscript'))
+
+Return('group')
diff --git a/components/libc/compilers/picolibc/syscall.c b/components/libc/compilers/picolibc/syscall.c
new file mode 100644
index 0000000000000000000000000000000000000000..882964a1f3c07bb4885d86b0342a941e847b5593
--- /dev/null
+++ b/components/libc/compilers/picolibc/syscall.c
@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2006-2023, RT-Thread Development Team
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2023-05-17     Flybreak     the first version
+ */
+
+#include <rtthread.h>
+
+int pico_get_errno(void)
+{
+    return rt_get_errno();
+}
diff --git a/libcpu/arm/cortex-m4/SConscript b/libcpu/arm/cortex-m4/SConscript
index b24349c4fc7f3d55d9cb215b5a8a1495e384294f..3ecbea8de35577ec036d530e8d622601b16ed62e 100644
--- a/libcpu/arm/cortex-m4/SConscript
+++ b/libcpu/arm/cortex-m4/SConscript
@@ -14,7 +14,7 @@ if rtconfig.PLATFORM in ['armcc', 'armclang']:
 if rtconfig.PLATFORM == 'armclang':
     src += Glob('*_rvds.S')
 
-if rtconfig.PLATFORM in ['gcc']:
+if rtconfig.PLATFORM in ['gcc', 'llvm-arm']:
     src += Glob('*_init.S')
     src += Glob('*_gcc.S')
 
diff --git a/tools/llvm_arm.py b/tools/llvm_arm.py
new file mode 100644
index 0000000000000000000000000000000000000000..e7910ce141a26a4f663dd4e49f5423faec31f0e1
--- /dev/null
+++ b/tools/llvm_arm.py
@@ -0,0 +1,57 @@
+#
+# File      : llvm_arm.py
+# This file is part of RT-Thread RTOS
+# COPYRIGHT (C) 2006 - 2018, RT-Thread Development Team
+#
+#  This program is free software; you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License as published by
+#  the Free Software Foundation; either version 2 of the License, or
+#  (at your option) any later version.
+#
+#  This program is distributed in the hope that it will be useful,
+#  but WITHOUT ANY WARRANTY; without even the implied warranty of
+#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#  GNU General Public License for more details.
+#
+#  You should have received a copy of the GNU General Public License along
+#  with this program; if not, write to the Free Software Foundation, Inc.,
+#  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+# Change Logs:
+# Date           Author       Notes
+# 2023-05-17     Flybreak     The first version
+
+import os
+import re
+import platform
+
+def GetLLVM_ARMRoot(rtconfig):
+    exec_path = rtconfig.EXEC_PATH
+    lib_path = 'lib/clang-runtimes/arm-none-eabi'
+    root_path = os.path.join(exec_path, '..', lib_path)
+
+    return root_path
+
+def CheckHeader(rtconfig, filename):
+    root = GetLLVM_ARMRoot(rtconfig)
+    config = re.findall(r"--config (.*)\.cfg", rtconfig.CFLAGS)
+    if config:
+        fn = os.path.join(root, config[0], 'include', filename)
+        if os.path.isfile(fn):
+            return True
+
+    return False
+
+def GetPicoLibcVersion(rtconfig):
+    version = None
+    root = GetLLVM_ARMRoot(rtconfig)
+    if CheckHeader(rtconfig, 'picolibc.h'): # get version from picolibc.h file
+        config = re.findall(r"--config (.*)\.cfg", rtconfig.CFLAGS)
+        fn = os.path.join(root, config[0], 'include', 'picolibc.h')
+        f = open(fn, 'r')
+        if f:
+            for line in f:
+                if line.find('__PICOLIBC_VERSION__') != -1 and line.find('"') != -1:
+                    version = re.search(r'\"([^"]+)\"', line).groups()[0]
+            f.close()
+    return version