SIM

Tags: arch:sim

This documentation page describes the contents of the build configurations available for the NuttX “sim” target. The sim target is a NuttX port that runs as a user-space program under Linux, Cygwin, or macOS. It is a very “low fidelity” embedded system simulation: This environment does not support any kind of asynchronous events; there are nothing like interrupts in this context. Therefore, there can be no preempting events.

The sim target is used primarily as a development and test platform for new RTOS features. It is also of academic interest. However, it has no known real-world application.

Fake Interrupts

In order to get timed behavior, the system timer “interrupt handler” is called from the sim target’s IDLE loop. The IDLE runs whenever there is no other task running. So, for example, if a task calls sleep(), then that task will suspend wanting for the time to elapse. If nothing else is available to run, then the IDLE loop runs and the timer increments, eventually re-awakening the sleeping task.

Context switching is based on logic similar to setjmp() and longjmp().

Timing Fidelity

Note

The sim target’s IDLE loop to delay on each call so that the system “timer interrupt” is called at a rate approximately correct for the system timer tick rate. This option can be enabled with CONFIG_SIM_WALLTIME_SIGNAL which will drive the entire simulation by using a host timer that ticks at CONFIG_USEC_PER_TICK. This option will no longer deliver ‘tick’ events from Idle task and it will generate them from the host signal handler. Another option is to use CONFIG_SIM_WALLTIME_SLEEP which will enable the tick events to be delayed from the Idle task by using a host sleep call.

Debugging

One of the best reasons to use the simulation is that is supports great Linux- based debugging. Here are the steps to follow in order to use the Linux ddd graphical front-end to GDB:

Enable debug symbols by ensuring CONFIG_DEBUG_SYMBOLS=y. You can enable this via the Kconfig menu (make menuconfig).

Re-build NuttX:

$ cd <NuttX-Directory>
$ make clean
$ make

Then start the debugging:
```
$ ddd nuttx &
gdb> b user_start
gdb> r
```

Note

This above steps work fine on Linux, Cygwin, and macOS. On Cygwin, you will need to start the Cygwin-X server before running ddd. On macOS, it’s probably easier to use lldb instead of gdb.

Issues

64-Bit Issues

As mentioned above, context switching is based on logic like setjmp() and longjmp(). This context switching is available for 32-bit and 64-bit targets.

You must, however, set the correct target in the configuration before you build: CONFIG_HOST_X86_64 or CONFIG_HOST_X86 for 64- and 32-bit targets, respectively. On a 64-bit machine, you can also force the 32-bit build with CONFIG_SIM_M32=y (which does not seem to be supported by more contemporary x86_64 compilers).

There are other 64-bit issues as well. For example, addresses are retained in 32-bit unsigned integer types in a few places. On a 64-bit machine, the 32- bit address storage may corrupt 64-bit addressing.

Note

This is really a bug; addresses should not be retained in uint32_t types but rather in uintptr_t types to avoid issues just like this.

Compiler differences

Operator new:

Problem: ‘operator new’ takes size_t ('...') as first parameter
Workaround: Add -fpermissive to the compilation flags

Stack Size Issues

When you run the NuttX simulation, it uses stacks allocated by NuttX from the NuttX heap. The memory management model is exactly the same in the simulation as in a real, target system. This is good because this produces a higher fidelity simulation.

However, when the simulation calls into the host OS libraries, it will still use these small simulation stacks. This happens, for example, when you call into the system to get and put characters to the console window or when you make X11 calls into the system. The programming model within those libraries will assume the host OS environment where the stack size grows dynamically and not the small, limited stacks of a deeply embedded system.

As a consequence, those system libraries may allocate large data structures on the stack and overflow the small NuttX stacks. X11, in particular, requires large stacks. If you are using X11 in the simulation, make sure that you set aside a “lot” of stack for the X11 library calls (maybe 8 or 16Kb). The stack size for the thread that begins with user start is controlled by the configuration setting CONFIG_INIT_STACKSIZE; you may need to increase this value to larger number to survive the X11 library calls.

If you are running X11 applications such as NSH add-on programs, then the stack size of the add-on program is controlled in another way. Here are the steps for increasing the stack size in that case:

$ cd ../apps/builtin    # Go to the builtin apps directory
$ vi builtin_list.h     # Edit this file and increase the stack size of the add-on
$ rm .built *.o         # This will force the builtin apps logic to rebuild

Symbol Collisions

The simulation build is a two pass build:

On the first pass, an intermediate, partially relocatable object is created called nuttx.rel. This includes all of the files that are part of the NuttX “domain.”
On the second pass, the files which are in the host OS domain are built and then linked with nuttx.rel to generate the simulation program.

NuttX is a POSIX compliant RTOS and is normally built on a POSIX compliant host environment (like Linux, Cygwin, or macOS). As a result, the same symbols are exported by both the NuttX domain and the host domain. How can we keep them separate?

This is done using the special file nuttx-name.dat. This file just contains a mapping of original function names to new function names. For example, the NuttX printf() will get the new name NXprintf().

This nuttx-names.dat file is used by the objcopy program between pass 1 and pass 2 to rename all of the symbols in the nuttx.rel object so that they do not collide with names provided by the host OS in the host PC domain.

Occasionally, as you test new functionality, you will find that you need to add more names to the nuttx-names.dat file. If there is a missing name mapping in nuttx-names.dat, the symptoms may be very obscure and difficult to debug. What happens in this case is that when logic in nuttx.rel intended to call the NuttX domain function, it instead calls into the host OS function of the same name.

Often you can survive such events. For example, it really should not matter which version of strlen() you call. Other times, it can cause subtle, mysterious errors. Usually, however, callng the wrong function in the wrong OS results in a fatal crash.

On macOS, instead of objcopy, -unexported_symbols_list linker option is used to hide symbols in the NuttX domain, using the same list of symbols from nuttx-name.dat.

Networking Issues

Please issue these commands to setup the reliable network on Ubuntu:

$ sudo apt-get -y install net-tools
$ sudo nuttx/tools/simbridge.sh eth0 on

Here are some tips you may need:

Must launch the executable with the root permission
Have to use virtual machine if host is in corporation network
Configure the network adapter in NAT mode if virtual machine is used

X11 Issues

There is an X11-based framebuffer driver that you can use to exercise the NuttX graphics subsystem on the simulator (see the sim/nx11 configuration below). This may require a lot of tinkering to get working, depending upon where your X11 installation stores libraries and header files and how it names libraries.

For example, on Ubuntu 9.09, I had to do the following to get a clean build:

$ cd /usr/lib/
$ sudo ln -s libXext.so.6.4.0 libXext.so

Note

I also get a segmentation fault at the conclusion of the NX test; that will need to get looked into as well.

Note

You may need issue this command with the latest Ubuntu before launch:

$ sudo xhost +

Cygwin64 Issues

There are some additional issues using the simulator with Cygwin64. Below is the summary of the changes that I had to make to get the simulator working in that environment:

CONFIG_HOST_X86_64=y, CONFIG_SIM_M32=n

Need to select X64_64. Cygwin64 tools do not seem to support any option to build a 32-bit target.
CONFIG_SIM_CYGWIN_DECORATED=n

Older versions of Cygwin tools decorated C symbol names by adding an underscore to the beginning of the symbol name. Newer versions of Cygwin do not seem to do this. Deselecting `CONFIG_SIM_CYGWIN_DECORATED` will select the symbols without the leading underscore as needed by the Cygwin64 toolchain.

How do you know if you need this option? You could look at the generated symbol tables to see if there are underscore characters at the beginning of the symbol names. Or, if you need this option, the simulation will not run. It will crash early, probably in some function due to the failure to allocate memory.

In this case, when I tried to run nutt.exe from the command line, it exited silently. Running with GDB I get the following (before hitting a breakpoint at main()):
```
(gdb) r
Starting program: /cygdrive/c/Users/Gregory/Documents/projects/nuttx/master/nuttx/nuttx.exe
[New Thread 6512.0xda8]
[New Thread 6512.0x998]
      1 [main] nuttx 6512 C:\Users\Gregory\Documents\projects\nuttx\master\nuttx\nuttx.exe: *** fatal error - Internal error: Out of memory for new path buf.
    736 [main] nuttx 6512 cygwin_exception::open_stackdumpfile: Dumping stack trace to nuttx.exe.stackdump
[Thread 6512.0x998 exited with code 256]
[Inferior 1 (process 6512) exited with code 0400]
```

CONFIG_SIM_X8664_SYSTEMV=n, CONFIG_SIM_X8664_MICROSOFT=y

Select Microsoft x64 calling convention.

The Microsoft x64 calling convention is followed on Microsoft Windows and pre-boot UEFI (for long mode on x86-64). It uses registers RCX, RDX, R8, R9 for the first four integer or pointer arguments (in that order), and XMM0, XMM1, XMM2, XMM3 are used for floating point arguments. Additional arguments are pushed onto the stack (right to left). Integer return values (similar to x86) are returned in RAX if 64 bits or less. Floating point return values are returned in XMM0. Parameters less than 64 bits long are not zero extended; the high bits are not zeroed.

SMP

This configuration has basic support for SMP testing. The simulation supports the emulation of multiple CPUs by creating multiple pthreads, each running a copy of the simulation in the same process address space.

You can enable SMP for ostest configuration by enabling these config options:

And you can enable some additional debug output with:

-# CONFIG_DEBUG_SCHED is not set
+CONFIG_DEBUG_SCHED=y

-# CONFIG_SCHED_INSTRUMENTATION is not set
-# CONFIG_SCHED_INSTRUMENTATION_SWITCH is not set
+CONFIG_SCHED_INSTRUMENTATION=y
+CONFIG_SCHED_INSTRUMENTATION_SWITCH=y

The SMP configuration will run with CONFIG_SMP_NCPUS=1. In this case there is, of course, no multi-CPU processing, but this does verify the correctness of some of the basic SMP logic.

BASIC

I have used the sim:nsh configuration to test Michael Haardt’s BASIC interpreter that you can find at apps/interpreters/bas.

Bas is an interpreter for the classic dialect of the programming language BASIC. It is pretty compatible to typical BASIC interpreters of the 1980s, unlike some other UNIX BASIC interpreters, that implement a different syntax, breaking compatibility to existing programs. Bas offers many ANSI BASIC statements for structured programming, such as procedures, local variables and various loop types. Further there are matrix operations, automatic LIST indentation and many statements and functions found in specific classic dialects. Line numbers are not required.

There is also a test suite for the interpreter that can be found at apps/examples/bastest.

Usage

This setup will initialize the BASIC test (optional). This will mount a ROMFS file system at /mnt/romfs that contains the BASIC test files:

nsh> bastest
Registering romdisk at /dev/ram6
Mounting ROMFS filesystem at target=/mnt/romfs with source=/dev/ram6
nsh>

The interactive interpreter is started like:

nsh> bas
bas 2.4
Copyright 1999-2014 Michael Haardt.
This is free software with ABSOLUTELY NO WARRANTY.
>

Ctrl-D exits the interpreter. The test programs can be ran like this:

nsh> bastest
Registering romdisk at /dev/ram0
Mounting ROMFS filesystem at target=/mnt/romfs with source=/dev/ram0
nsh> bas /mnt/romfs/test01.bas
 1
hello
 0.0002
 0.0000020
 0.0000002

nsh>

Or you can load a test into memory and execute it interactively:

nsh> bas
bas 2.4
Copyright 1999-2014 Michael Haardt.
This is free software with ABSOLUTELY NO WARRANTY.
> load "/mnt/romfs/test01.bas"
> run
 1
hello
 0.0002
 0.0000020
 0.0000002
>

Configurations

Each configuration is maintained in a sub-directory and can be selected as follows:

$ ./tools/configure.sh sim:<config>

Where <config> is one of the configurations listed below.

Before building, make sure that the configuration is correct for your host platform.

Linux, 32-bit CPU:
- CONFIG_HOST_LINUX=y
- CONFIG_HOST_WINDOWS=n
- CONFIG_HOST_X86=y
- CONFIG_HOST_X86_64=n
- CONFIG_HOST_ARM64=n
Linux, 64-bit CPU, 32-bit build:
- CONFIG_HOST_LINUX=y
- CONFIG_HOST_WINDOWS=n
- CONFIG_HOST_X86=n
- CONFIG_HOST_X86_64=y
- CONFIG_HOST_ARM64=n
- CONFIG_SIM_X8664_MICROSOFT=n
- CONFIG_SIM_X8664_SYSTEMV=y
- CONFIG_SIM_M32=y
Linux, 64-bit CPU, 64-bit build:
- CONFIG_HOST_LINUX=y
- CONFIG_HOST_WINDOWS=n
- CONFIG_HOST_X86=n
- CONFIG_HOST_X86_64=y
- CONFIG_HOST_ARM64=n
- CONFIG_SIM_X8664_MICROSOFT=n
- CONFIG_SIM_X8664_SYSTEMV=y
- CONFIG_SIM_M32=n
Cygwin, 32-bit:
- CONFIG_HOST_LINUX=n
- CONFIG_HOST_WINDOWS=y
- CONFIG_WINDOWS_CYGWIN=y
- CONFIG_HOST_X86=y
- CONFIG_HOST_X86_64=n
- CONFIG_HOST_ARM64=n
Cygwin64, 64-bit, 32-bit build

I don’t believe this configuration is supported by Cygwin64.
Cygwin64, 64-bit, 64-bit build:
- CONFIG_HOST_LINUX=n
- CONFIG_HOST_WINDOWS=y
- CONFIG_WINDOWS_CYGWIN=y
- CONFIG_HOST_X86=n
- CONFIG_HOST_X86_64=y
- CONFIG_HOST_ARM64=n
- CONFIG_SIM_X8664_MICROSOFT=y
- CONFIG_SIM_X8664_SYSTEMV=n
- CONFIG_SIM_M32=n
macOS, 64-bit, 64-bit build:
- CONFIG_HOST_LINUX=n
- CONFIG_HOST_MACOS=y
- CONFIG_HOST_WINDOWS=n
- CONFIG_HOST_X86=n
- CONFIG_HOST_X86_64=y
- CONFIG_HOST_ARM64=n
- CONFIG_SIM_X8664_MICROSOFT=n
- CONFIG_SIM_X8664_SYSTEMV=y
- CONFIG_SIM_M32=n
macOS M1, 64-bit, 64-bit build:
- CONFIG_HOST_LINUX=n
- CONFIG_HOST_MACOS=y
- CONFIG_HOST_WINDOWS=n
- CONFIG_HOST_X86=n
- CONFIG_HOST_X86_64=n
- CONFIG_HOST_ARM64=y
- CONFIG_SIM_X8664_MICROSOFT=n
- CONFIG_SIM_X8664_SYSTEMV=y
- CONFIG_SIM_M32=n
Linux ARM64, 64-bit, 64-bit build:
- CONFIG_HOST_LINUX=y
- CONFIG_HOST_MACOS=n
- CONFIG_HOST_WINDOWS=n
- CONFIG_HOST_X86=n
- CONFIG_HOST_X86_64=n
- CONFIG_HOST_ARM64=y
- CONFIG_SIM_X8664_MICROSOFT=n
- CONFIG_SIM_X8664_SYSTEMV=y
- CONFIG_SIM_M32=n

Todo

Not all of the available sim configurations are documented below.

adb

A simple demo show how to config adb.

$ ./nuttx
NuttShell (NSH) NuttX-10.2.0
nsh> adbd &
adbd [2:100]

You can use the normal adb command from host:

$ adb kill-server
$ adb connect localhost:5555
$ adb shell

alsa

This configuration enables testing audio applications on NuttX by implementing an audio-like driver that uses ALSA to forward the audio to the host system. It also enables the hostfs to enable direct access to the host system’s files mounted on the simulator. The ALSA audio driver allows uncompressed PCM files - as well as MP3 files - to be played.

To check the audio devices:

$ ./nuttx
NuttShell (NSH) NuttX-10.4.0
nsh> ls /dev/audio
/dev/audio:
pcm0c
pcm0p
pcm1c
pcm1p

pcm0c represents the device to capture uncompressed PCM audio
pcm0p represents the device to playback uncompressed PCM files
pcm1c represents the device to capture MP3-encoded audio
pcm1p represents the device to playback MP3-encoded files

Mounting Files from Host System

To mount files from the host system and enable them to be played in the sim:

nsh> mount -t hostfs -o fs=/path/to/audio/files/ /host
nsh> ls /host
/host:
mother.mp3
mother.wav
.
..

Playing uncompressed-PCM files

To play uncompressed-PCM files, we can use nxplayer’s playraw command. We need 1) select the appropriate audio device to playback this file and 2) know in advance the file’s parameters (channels, bits/sample and sampling rate):

nsh> nxplayer
NxPlayer version 1.05
h for commands, q to exit

nxplayer> device /dev/audio/pcm0p
nxplayer> playraw /host/mother.wav 2 16 44100

In this example, the file mother.wav is a stereo (2-channel), 16 bits/sample and 44,1KHz PCM-encoded file.

Playing MP3-encoded files

To play MP3 files, we can use nxplayer’s play command directly. We only need to select the appropriate audio device to playback this file:

nsh> nxplayer
NxPlayer version 1.05
h for commands, q to exit

nxplayer> device /dev/audio/pcm1p
nxplayer> play /host/mother.mp3

bluetooth

Supports some very limited, primitive, low-level debug of the Bluetooth stack using the Bluetooth “Swiss Army Knife” at apps/wireless/bluetooth/btsak and the NULL Bluetooth device at drivers/wireless/bluetooth/bt_null.c.

There is also support on a Linux Host for attaching the bluetooth hardware from the host to the NuttX bluetooth stack via the HCI Socket interface over the User Channel. This is enabled in the bthcisock configuration. In order to use this you must give the nuttx ELF additional capabilities:

$ sudo setcap 'cap_net_raw,cap_net_admin=eip' ./nuttx

You can then monitor the HCI traffic on the host with WireShark or btmon:

$ sudo btmon

configdata

A unit test for the MTD configuration data driver.

cxxtest

The C++ standard library test at apps/testing/cxxtest configuration. This test is used to verify the uClibc++ port to NuttX.

Note

Before you can use this example, you must first install the uClibc++ C++ library. This is located outside of the NuttX source tree in the NuttX uClibc++ GIT repository. See the README.txt file there for instructions on how to install uClibc++

Note

At present (2012/11/02), exceptions are disabled in this example (CONFIG_CXX_EXCEPTION=n). It is probably not necessary to disable exceptions.

Note

Unfortunately, this example will not run now.

The reason that the example will not run on the simulator has to do with when static constructors are enabled: In the simulator it will attempt to execute the static constructors before main() starts. BUT… NuttX is not initialized and this results in a crash.

To really use this example, I will have to think of some way to postpone running C++ static initializers until NuttX has been initialized.

fb

A simple configuration used for some basic (non-graphic) debug of the framebuffer character drivers using apps/examples/fb.

ipforward

This is an NSH configuration that includes a simple test of the NuttX IP forwarding logic using apps/examples/ipforward. That example uses two TUN network devices to represent two networks. The test then sends packets from one network destined for the other network. The NuttX IP forwarding logic will recognize that the received packets are not destined for it and will forward the logic to the other TUN network. The application logic then both sends the packets on one network and receives and verifies the forwarded packet received on the other network. The received packets differ from the sent packets only in that the hop limit (TTL) has been decremented.

Be default, this test will forward TCP packets. The test can be modified to support forwarding of ICMPv6 multicast packets with these changes to the configuration:

-CONFIG_EXAMPLES_IPFORWARD_TCP=y
+CONFIG_EXAMPLES_IPFORWARD_ICMPv6=y

+CONFIG_NET_ICMPv6=y
+CONFIG_NET_ICMPv6_SOCKET=y
+CONFIG_NET_ETHERNET=y
+CONFIG_NET_IPFORWARD_BROADCAST=y

Additional required settings will also be selected when you manually select the above via make menuconfig.

loadable

This configuration provides an example of loadable apps. It cannot be used with any Windows configuration, however, because Windows does not use the ELF format.

This is the key part of the configuration:

+CONFIG_PATH_INITIAL="/system/bin"
+CONFIG_INIT_FILEPATH="/system/bin/nsh"

The shell is loaded from the ELF, but you can also run any of the ELFs that are in /system/bin as they are on the PATH.

minibasic

This configuration was used to test the Mini Basic port at apps/interpreters/minibasic.

module

This is a configuration to test CONFIG_LIBC_ELF with 64-bit modules. This has apps/examples/module enabled. This configuration is intended for 64-bit host OS.

module32

This is a configuration to test CONFIG_LIBC_ELF with CONFIG_SIM_M32 and 32-bit modules. This has apps/examples/module enabled. This configuration is intended for 64-bit host OS.

mount

Configures to use apps/examples/mount.

mtdpart

This is the apps/examples/mtdpart test using a MTD RAM driver to simulate the FLASH part.

mtdrwb

This is the apps/examples/mtdrwb test using a MTD RAM driver to simulate the FLASH part.

nettest

Configures to use apps/examples/nettest. This configuration enables networking using the network TAP device.

Note

As of NuttX-5.18, when built on Windows, this test does not try to use the TAP device (which is not available on Cygwin anyway), but inside will try to use the Cygwin WPCAP library. Only the most preliminary testing has been performed with the Cygwin WPCAP library, however.

Note

The IP address is hard-coded in arch/sim/src/up_wpcap.c. You will either need to edit your configuration files to use 10.0.0.1 on the “target” (CONFIG_EXAMPLES_NETTEST_*) or edit up_wpcap.c to select the IP address that you want to use.

nimble

This is similar to bthcisock configuration, which uses the exposes the real BLE stack to NuttX, but disables NuttX’s own BLE stack and uses nimBLE stack instead (built in userspace).

This configuration can be tested by running nimBLE example application “nimble” as follows:

$ sudo setcap 'cap_net_raw,cap_net_admin=eip' nuttx
$ ./nuttx
NuttShell (NSH) NuttX-9.1.0
nsh> ifup bnep0
ifup bnep0...OK
nsh> nimble
hci init
port init
gap init
gatt init
ans init
ias init
lls init
tps init
hci_sock task init
ble_host task init
hci sock task
host task
advertise

At this point you should be able to detect a “nimble” BLE device when scanning for BLE devices. You can use nRFConnect Android application from Nordic to connect and inspect exposed GATT services.

nsh

Configures to use the NuttShell at apps/examples/nsh. This version has one builtin function, apps/examples/hello.

Note

This configuration has BINFS enabled so that the builtin applications can be made visible in the file system. Because of that, the builtin applications do not work as other examples.

The binfs filesystem will be mounted at /bin when the system starts up:

nsh> ls /bin
/bin:
  hello
nsh> echo $PATH
/bin
nsh> hello
Hello, World!!
nsh>

Notice that the executable hello is found using the value in the PATH variable (which was preset to /`bin`). If the PATH variable were not set then you would have to use /bin/hello on the command line.

nsh2

This is another example that is configured to use the NuttShell at apps/examples/nsh. Like sim:nsh, this version uses NSH built-in functions. The nx, nxhello, and nxlines examples are included as built-in functions.

Note

X11 Configuration:

This configuration uses an X11-based framebuffer driver. Of course, this configuration can only be used in environments that support X11! (And it may not even be usable in all of those environments without some “tweaking” See discussion below under the nx11 configuration).

For examples, it expects to be able to include X11/Xlib.h. That currently fails on my Linux box.

nx

Configured to use apps/examples/nx.

Note

Special simulated framebuffer configuration options:

CONFIG_SIM_FBHEIGHT: Height of the framebuffer in pixels
CONFIG_SIM_FBWIDTH: Width of the framebuffer in pixels.
CONFIG_SIM_FBBPP: Pixel depth in bits

Note

This version has NO DISPLAY and is only useful for debugging NX internals in environments where X11 is not supported. There is an additional configuration that may be added to include an X11-based simulated framebuffer driver:

CONFIG_SIM_X11FB: Use X11 window for framebuffer

See the “nx11” configuration below for more information.

nx11

Configures to use apps/examples/nx. This configuration is similar to the nx configuration except that it adds support for an X11-based framebuffer driver. Of course, this configuration can only be used in environments that support X11! (And it may not even be usable in all of those environments without some “tweaking”).

Note

This configuration uses the same special simulated framebuffer configuration options as the nx configuration:

* ``CONFIG_SIM_X11FB``: Use X11 window for framebuffer
* ``CONFIG_SIM_FBHEIGHT``: Height of the framebuffer in pixels
* ``CONFIG_SIM_FBWIDTH``: Width of the framebuffer in pixels.
* ``CONFIG_SIM_FBBPP``: Pixel depth in bits

Note

But now, since CONFIG_SIM_X11FB is also selected the following definitions are needed:

CONFIG_SIM_FBBPP (must match the resolution of the display)
CONFIG_FB_CMAP=y

My system has 24-bit color, but packed into 32-bit words so the correct setting of CONFIG_SIM_FBBPP is 32.

For whatever value of CONFIG_SIM_FBBPP is selected, the corresponding CONFIG_NX_DISABLE_*BPP setting must not be disabled.

Note

A X11 mouse-based touchscreen simulation can also be enabled by setting:

* ``CONFIG_INPUT=y``
* ``CONFIG_SIM_TOUCHSCREEN=y``

If you do not have the call to sim_tcinitialize(0), the build will mysteriously fail claiming that it can’t find up_tcenter() and up_tcleave(). That is a consequence of the crazy way that the simulation is built and can only be eliminated by calling up_simtouchscreen(0) from your application.
You must first call up_fbinitialize(0) before calling up_simtouchscreen() or you will get a crash.
Call sim_tcunininitializee() when you are finished with the simulated touchscreen.
Enable CONFIG_DEBUG_INPUT=y for touchscreen debug output.

Note

To get the system to compile under various X11 installations you may have to modify a few things. For example, in order to find libXext, I had to make the following change under Ubuntu 9.09:

$ cd /usr/lib/
$ sudo ln -s libXext.so.6.4.0 libXext.so

Note

This configuration is also set up to use the apps/examples/nxterm test instead of apps/examples/nx. To enable this configuration, First, select Multi-User mode as described above. Then, add the following definitions to the defconfig file:

-CONFIG_NXTERM=n
+CONFIG_NXTERM=y

-CONFIG_EXAMPLES_NX=y
+CONFIG_EXAMPLES_NX=n

-CONFIG_EXAMPLES_NXTERM=n
+CONFIG_EXAMPLES_NXTERM=y

nxffs

This is a test of the NXFFS file system using the apps/testing/nxffs test with an MTD RAM driver to simulate the FLASH part.

nxlines

This is the apps/examples/nxlines test.

nxwm

This is a special configuration setup for the NxWM window manager UnitTest. The NxWM window manager can be found here at apps/graphics/NxWidgets/nxwm. The NxWM unit test can be found at apps/graphics/NxWidgets/UnitTests/nxwm.

Note

There is an issue with running this example under the simulation: In the default configuration, this example will run the NxTerm example which waits on readline() for console input. When it calls readline(), the whole system blocks waiting from input from the host OS. So, in order to get this example to run, you must comment out the readline() call in apps/nshlib/nsh_consolemain.c like:

Index: nsh_consolemain.c
===================================================================
--- nsh_consolemain.c   (revision 4681)
+++ nsh_consolemain.c   (working copy)
@@ -117,7 +117,8 @@
   /* Execute the startup script */

 #ifdef CONFIG_ETC_ROMFS
-  nsh_script(&pstate->cn_vtbl, "init", NSH_INITPATH);
+// REMOVE ME
+//  nsh_script(&pstate->cn_vtbl, "init", NSH_INITPATH);
 #endif

   /* Then enter the command line parsing loop */
@@ -130,7 +131,8 @@
       fflush(pstate->cn_outstream);

       /* Get the next line of input */
-
+sleep(2); // REMOVE ME
+#if 0 // REMOVE ME
       ret = readline(pstate->cn_line, LINE_MAX,
                      INSTREAM(pstate), OUTSTREAM(pstate));
       if (ret > 0)
@@ -153,6 +155,7 @@
                   "readline", NSH_ERRNO_OF(-ret));
           nsh_exit(&pstate->cn_vtbl, 1);
         }
+#endif // REMOVE ME
     }

   /* Clean up */

The above workaround should no longer be necessary. However, the above is left in place until the solution is verified.

Warning

2019-05-04

Something has changed. Today this configuration failed to build because is requires CONFIG_NX_XYINPUT=y in the configuration. That indicates mouse or touchscreen support. Apparently, the current NxWM will not build without this support.

ostest

The “standard” NuttX apps/examples/ostest configuration.

pf_ieee802154

This is the configuration that used for unit level test of the socket support for the PF_IEEE802154 address family. It uses the IEEE 802.15.4 loopback network driver and the test at apps/examples/pf_ieee802154.

Basic usage example:

nsh> pfserver ab:cd &
nsh> pfclient ab:cd

pktradio

This configuration is identical to the sixlowpan configuration described below EXCEPT that it uses the generic packet radio loopback network device.

rpproxy and rpserver

This is an example implementation for OpenAMP based on the share memory.

rpproxy:

Remote slave(client) proxy process. rpproxy creates a proxy between client and server to allow the client to access the hardware resources on different process.

rpserver:

Remote master (host) server process. rpserver contains all the real hardware configuration, such as:

Universal Asynchronous Receiver/Transmitter (UART).
Specific File System.
Network protocol stack and real network card device.

Rpmsg driver used in this example include:

Rpmsg Syslog

Redirect log to master core Linux kernel, NuttX, Freertos …
Work as early as possible Two phase initialization
Never lost the log Hang during boot or runtime Full system crash(panic, watchdog …)

Rpmsg TTY(UART)

Like pseudo terminal but between two CPU
No different from real tty(open/read/write/close)
Full duplex communication
Support multiple channels as need * Connect RTOS shell * Make integrated GPS like external(NMEA) * Make integrated modem like external(ATCMD)

RpmsgFS

Like NFS but between two CPU
Fully access remote(Linux/NuttX) File system * Save the tuning parameter during manufacture * Load the tuning parameter file in production * Save audio dump to file for tuning/debugging * Dynamic loading module from remote

Rpmsg Net

Rpmsg UsrSock client
Rpmsg UsrSock server
Rpmsg Net driver
Rpmsg MAC/PHY adapter

To use this example:

Build images

Build rpserver and backup the image:
$ ./tools/configure.sh sim:rpserver
$ make
$ cp nuttx ~/rpserver
Distclean the build environment.
Build rpproxy:
$ ./tools/configure.sh sim:rpproxy
$ make
$ cp nuttx ~/rpproxy

Test the Rpmsg driver

Rpmsg Syslog:

Start rpserver:

  $ sudo ~/rpserver
  [    0.000000] server: SIM: Initializing

  NuttShell (NSH)
  server>

Start rpproxy:

$ sudo ~/rpproxy

Check the syslog from rpproxy in rpserver terminal:

server> [    0.000000] proxy: SIM: Initializing

Rpmsg TTY(UART):

Use cu switch the current CONSOLE to the proxy:

server> ps
  PID GROUP PRI POLICY   TYPE    NPX STATE    EVENT     SIGMASK   STACK COMMAND
    0     0   0 FIFO     Kthread N-- Ready              00000000 000000 Idle Task
    1     1 224 FIFO     Kthread --- Waiting  Signal    00000000 002032 hpwork
    2     1 100 FIFO     Task    --- Running            00000000 004080 init
    3     3 224 FIFO     Kthread --- Waiting  Signal    00000002 002000 rptun proxy 0x56634fa0
server> cu /dev/ttyproxy
proxy> ps
  PID GROUP PRI POLICY   TYPE    NPX STATE    EVENT     SIGMASK   STACK COMMAND
    0     0   0 FIFO     Kthread N-- Ready              00000000 000000 Idle Task
    1     1 224 FIFO     Kthread --- Waiting  Signal    00000000 002032 hpwork
    3     3 100 FIFO     Task    --- Running            00000000 004080 init

To switch back the console, type "~." in the cu session.

RpmsgFS:

Mount the remote file system via RPMSGFS, cu to proxy first:

server> cu
proxy> mount -t rpmsgfs -o cpu=server,fs=/proc proc_server
proxy> ls
/:
  dev/
  etc/
  proc/
  proc_server/
  tmp/

Check the uptime:

proxy> cat proc/uptime
  833.21
proxy> cat proc_server/uptime
  821.72

Rpmsg UsrSock:

“rptun proxy” kernel thread is running:

server> ps
  PID GROUP PRI POLICY   TYPE    NPX STATE    EVENT     SIGMASK   STACK COMMAND
    0     0   0 FIFO     Kthread N-- Ready              00000000 000000 Idle Task
    1     1 224 FIFO     Kthread --- Waiting  Signal    00000000 002032 hpwork
    2     1 100 FIFO     Task    --- Running            00000000 004080 init
    3     3 224 FIFO     Kthread --- Waiting  Signal    00000002 002000 rptun proxy 0x56634fa0

Send ICMP ping to network server via rpmsg usrsock:

server> cu
proxy> ping 127.0.0.1
PING 127.0.0.1 56 bytes of data
bytes from 127.0.0.1: icmp_seq=0 time=20 ms
bytes from 127.0.0.1: icmp_seq=1 time=10 ms
bytes from 127.0.0.1: icmp_seq=2 time=10 ms
bytes from 127.0.0.1: icmp_seq=3 time=10 ms
bytes from 127.0.0.1: icmp_seq=4 time=10 ms
bytes from 127.0.0.1: icmp_seq=5 time=10 ms
bytes from 127.0.0.1: icmp_seq=6 time=20 ms
bytes from 127.0.0.1: icmp_seq=7 time=10 ms
bytes from 127.0.0.1: icmp_seq=8 time=10 ms
bytes from 127.0.0.1: icmp_seq=9 time=10 ms
packets transmitted, 10 received, 0% packet loss, time 10100 ms

Please read NETWORK-LINUX.txt if you want to try the real address.

sixlowpan

This configuration was intended only for unit-level testing of the 6LoWPAN stack. It enables networking with 6LoWPAN support and uses only a IEEE802.15.4 MAC loopback network device to supported testing.

This configuration includes apps/examples/nettest and apps/examples/udpblaster. Neither are truly functional. The only intent of this configuration is to verify that the 6LoWPAN stack correctly encodes IEEE802.15.4 packets on output to the loopback device and correctly decodes the returned packet.

rtptools

RTP Tools is a set of small applications that can be used for processing RTP data.

rtpplay: playback RTP sessions recorded by rtpdump
rtpsend: generate RTP packets from the textual description, generated by hand or rtpdump
rtpdump: parse and print RTP packets, generating output files suitable for rtpplay and rtpsend
rtptrans: RTP translator between unicast and multicast networks

This configuration is based on the sim:tcpblaster and builds the rtpdump. This application is able to receive RTP packets and print the contents. As a real-world application, one could write the received content to a FIFO and play it with nxplayer.

To build it, follow the instructions for Accessing the Network.

Tip

One can use pulseaudio to send RTP packets through the network:

$ pactl load-module module-null-sink sink_name=rtp format=s16le channels=2 rate=44100 sink_properties="device.description='RTP'"
$ pactl load-module module-rtp-send source=rtp.monitor format=s16le destination_ip=10.0.1.2 port=46998

The loaded sink RTP is used to send PC’s audio to the 10.0.1.2:46998 address (SIM’s IP).

After being able to access the network through the simulator, run:

nsh> rtpdump -F short /46998 &
rtpdump [5:100]
nsh> 42949704.930000 1277462397 15308
42949704.930000 1277462714 15309

For a real-world application, check RTP Tools on ESP32-LyraT board.

spiffs

This is a test of the SPIFFS file system using the apps/testing/fstest test with an MTD RAM driver to simulate the FLASH part.

sotest

This is a configuration to test CONFIG_LIBC_ELF with 64-bit modules. This has apps/examples/sotest enabled. This configuration is intended for 64-bit host OS.

sotest32

This is a configuration to test CONFIG_LIBC_ELF with `CONFIG_SIM_M32` and 32-bit modules. This has apps/examples/sotest enabled. This configuration is intended for 64-bit host OS.

sqlite

This configuration is used to test sqlite. Since hostfs does not support FIOC_FILEPATH, it cannot currently be used in hostfs.

Basic usage example:

nsh> cd tmp
nsh> sqlite3 test.db
SQLite version 3.45.1 2024-01-30 16:01:20
Enter ".help" for usage hints.
sqlite>
CREATE TABLE COMPANY(
  ID INT PRIMARY KEY     sqlite> (x1...> NOT NULL,
  NAME           TEXT    NOT NULL,
  AGE            (x1...> (x1...> INT     NOT NULL,
  ADDRESS        CHAR(50),
  SALARY         (x1...> (x1...> REAL
);(x1...>
sqlite> .quit
sqlite>
nsh>
nsh> ls -l
/tmp:
-rwxrwxrwx       12288 test.db

tcploop

This configuration performs a TCP “performance” test using apps/examples/tcpblaster and the IPv6 local loopback device. Performance is in quotes because, while that is the intent of the tcpblaster example, this is not an appropriate configuration for TCP performance testing. Rather, this configuration is useful only for verifying TCP transfers over the loopback device.

To use IPv4, modify these settings in the defconfig file:

-# CONFIG_NET_IPv4 is not set
-CONFIG_NET_IPv6=y
-CONFIG_NET_IPv6_NCONF_ENTRIES=4

touchscreen

This configuration uses the simple touchscreen test at apps/examples/touchscreen. This test will create an empty X11 window and will print the touchscreen output as it is received from the simulated touchscreen driver.

Since this example uses the simulated frame buffer driver, most of the configuration settings discussed for the nx11 configuration also apply here. See that discussion above.

See apps/examples/README.txt for further information about build requirements and configuration settings.

toywasm

This is a configuration with toywasm.

An example usage:

NuttShell (NSH) NuttX-10.4.0
nsh> mount -t hostfs -o fs=/tmp/wasm /mnt
nsh> toywasm --wasi /mnt/hello.wasm
hello
nsh>

udgram

This is the same as the nsh configuration except that it includes two additional built in applications: server and client. These applications are provided by the test at apps/examples/udgram. This configuration enables local, Unix domain sockets and supports the test of the datagram sockets.

To use the test:

nsh> server &
nsh> client

unionfs

This is a version of NSH dedicated to performing the simple test of the Union File System at apps/examples/unionfs. The command unionfs will mount the Union File System at /mnt/unionfs. You can than compare what you see at /mnt/unionfs with the content of the ROMFS file systems at apps/examples/unionfs/atestdir and btestdir.

Here is some sample output from the test:

NuttShell (NSH)
nsh> unionfs
Mounting ROMFS file system 1 at target=/mnt/a with source=/dev/ram4
Mounting ROMFS file system 2 at target=/mnt/b with source=/dev/ram5
nsh> ls /mnt/unionfs
/mnt/unionfs:
 .
 afile.txt
 offset/

When unionfs was created, file system was joined with an offset called “offset”. Therefore, all of the file system 2 root contents will appear to reside under a directory called offset/ (although there is no directory called offset/ on file system 2). File system 1 on the other hand does have an actual directory called offset/. If we list the contents of the offset/ directory in the unified file system, we see the merged contents of the file system 1 offset/ directory and the file system 2 root directory:

nsh> cat /mnt/unionfs/afile.txt
This is a file in the root directory on file system 1

nsh> ls /mnt/unionfs/offset
/mnt/unionfs/offset:
 afile.txt
 .
 adir/
 bfile.txt
 bdir/
nsh> cat /mnt/unionfs/offset/afile.txt

This is a file in the offset/ directory on file system 1.

nsh> cat /mnt/unionfs/offset/bfile.txt

This is another file in the root directory on file system 2.

The directory offset/adir exists on file system 1 and the directory adir/ exists on file system 2. You can see that these also overlap:

nsh> ls /mnt/unionfs/offset/adir
/mnt/unionfs/offset/adir:
 ..
 asubdir/
 adirfile.txt
 bsubdir/
 bdirfile.txt
 .

The unified directory listing is showing files from both file systems in their respective offset adir/ subdirectories. The file adirfile.txt exists in both file system 1 and file system 2 but the version in file system 2 is occluded by the version in file system 1. The only way that you can know which you are looking at is by cat’ing the file:

nsh> cat /mnt/unionfs/offset/adir/adirfile.txt

This is a file in directory offset/adir on file system 1.

The file on file system 1 has correctly occluded the file with the same name on file system 2. bdirfile.txt, however, only exists on file system 2, so it is not occluded:

nsh> cat /mnt/unionfs/offset/adir/bdirfile.txt

This is another file in directory adir on file system 2.

You can see the files in the two file systems before they were unified at apps/examples/unionfs/atestdir and btestdir.

userfs

This is another NSH configuration that includes the built-in application of apps/examples/userfs to support test of the UserFS on the simulation platform.

To use the test:

nsh> userfs                 # Mounts the UserFS test file system at
                            # /mnt/ufstest
nsh> mount                  # Testing is then performed by exercising the
                            # file system from the command line
nsh> ls -l /mnt/ufstest
nsh> cat /mnt/ufstest/File1

ustream

This is the same as the nsh configuration except that it includes two addition built in applications: server and client. These applications are provided by the test at apps/examples/ustream. This configuration enables local, Unix domain sockets and supports the test of the stream sockets.

To use the test:

nsh> server &
nsh> client

Note

The binfs file system is mounted at /bin when the system starts up.

vncserver

This a simple vnc server test configuration, Remmina is tested and recommended since there are some compatibility issues. By default SIM will be blocked at startup to wait client connection, if a client connected, then the fb example will launch.

vpnkit

This is a configuration with VPNKit support. See NETWORK-VPNKIT.txt.

wamr

This is a configuration for WebAssembly sample.

Compile Toolchain

Download WASI sdk and export the WASI_SDK_PATH path:

$ wget https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-19/wasi-sdk-19.0-linux.tar.gz
$ tar xf wasi-sdk-19.0-linux.tar.gz
# Put wasi-sdk-19.0 to your host WASI_SDK_PATH environment variable, like:
$ export WASI_SDK_PATH=`pwd`/wasi-sdk-19.0

Download Wamr “wamrc” AOT compiler and export to the PATH:

$ mkdir wamrc
$ wget https://github.com/bytecodealliance/wasm-micro-runtime/releases/download/WAMR-1.1.2/wamrc-1.1.2-x86_64-ubuntu-20.04.tar.gz
$ tar xf wamrc-1.1.2-x86_64-ubuntu-20.04.tar.gz
$ export PATH=$PATH:$PWD

Configuring and running

Configuring sim:wamr and compile:

$ ./tools/configure.sh sim:wamr
$ make
...
Wamrc Generate AoT: /home/archer/code/nuttx/n5/apps/wasm/hello.aot
Wamrc Generate AoT: /home/archer/code/nuttx/n5/apps/wasm/coremark.aot
LD:  nuttx

Copy the generated wasm file (Interpreter/AoT)

$ cp ../apps/wasm/hello.aot .
$ cp ../apps/wasm/hello.wasm .
$ cp ../apps/wasm/coremark.wasm .

Run iwasm

$ ./nuttx
NuttShell (NSH) NuttX-10.4.0
nsh> iwasm /data/hello.wasm
Hello, World!!
nsh> iwasm /data/hello.aot
Hello, World!!
nsh> iwasm /data/coremark.wasm
2K performance run parameters for coremark.
CoreMark Size    : 666
Total ticks      : 12000
Total time (secs): 12.000000
Iterations/Sec   : 5.000000
Iterations       : 60
Compiler version : Clang 15.0.7
Compiler flags   : Using NuttX compilation options
Memory location  : Defined by the NuttX configuration
seedcrc          : 0xe9f5
[0]crclist       : 0xe714
[0]crcmatrix     : 0x1fd7
[0]crcstate      : 0x8e3a
[0]crcfinal      : 0xa14c
Correct operation validated. See README.md for run and reporting rules.
CoreMark 1.0 : 5.000000 / Clang 15.0.7 Using NuttX compilation options / Defined by the NuttX configuration

usbdev

This is a configuration with sim usbdev support.

Raw Gadget setup

Get Raw Gadget code at https://github.com/xairy/raw-gadget.

Run make in the raw_gadget and dummy_hcd directory. If raw_gadget build fail, you need to check which register interface meets your kernel version, usb_gadget_probe_driver or usb_gadget_register_driver.

Run ./insmod.sh in the raw_gadget and dummy_hcd directory.

Configuration

sim:usbdev contains two different sets of composite devices:
- conn0: adb & rndis
- conn1: cdcacm & cdcecm
- conn2: cdcncm
- conn3: cdcmbim

You can use the sim:usbdev configuration.

How to run

Run nuttx with root mode. Then, run ADB.

$ conn 0
$ adbd &

Enter the ADB command on the host machine:

$ adb kill-server
$ adb devices
List of devices attached
* daemon not running; starting now at tcp:5037
* daemon started successfully
0101        device

If the ADB connection fails, make sure the udev rule is added correctly. Edit /etc/udev/rules.d/51-android.rules file and add the following to it:

SUBSYSTEM=="usb", ATTR{idVendor}=="1630", ATTR{idProduct}=="0042", MODE="0666", GROUP="plugdev"

Then you can use commands such as adb shell, adb push, adb pull as normal.

Next, run RNDIS:

On NuttX, enter command:

$ conn 0
$ ifconfig
eth0    Link encap:Ethernet HWaddr 00:00:00:00:00:00 at UP
        inet addr:0.0.0.0 DRaddr:0.0.0.0 Mask:0.0.0.0
$ dhcpd_start eth0
eth0    Link encap:Ethernet HWaddr 00:00:00:00:00:00 at UP
      inet addr:10.0.0.1 DRaddr:10.0.0.1 Mask:255.255.255.0

On the host machine, you can see the network device named usb0:

$ ifconfig
usb0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 602
        inet 10.0.0.4  netmask 255.255.255.0  broadcast 10.0.0.255
        ether 36:50:3d:62:b5:80  txqueuelen 1000  (以太网)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 43  bytes 8544 (8.5 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Then you can test the network connection using the ping command or telnet.

Next, run CDCACM:

On NuttX, enter the command:

$ conn 1

If the connection is successful, you can see /dev/ttyACM devices on both NuttX and host PC.

Then you can use echo and cat command to test. On NuttX:

  nsh> echo hello > /dev/ttyACM0

On the host machine:

.. code:: console

   $ cat /dev/ttyACM0
   hello

Next, run CDCECM:

On NuttX, run:

$ conn 1
$ ifconfig
eth0    Link encap:Ethernet HWaddr 00:e0:de:ad:be:ef at UP
        inet addr:0.0.0.0 DRaddr:0.0.0.0 Mask:0.0.0.0
$ dhcpd_start eth0
$ ifconfig
eth0    Link encap:Ethernet HWaddr 00:e0:de:ad:be:ef at UP
         inet addr:10.0.0.1 DRaddr:10.0.0.1 Mask:255.255.255.0

On the host, you can see the network device named `enx020000112233`:

$ ifconfig
enx020000112233: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 576
        inet 10.0.0.4  netmask 255.255.255.0  broadcast 10.0.0.255
        ether 02:00:00:11:22:33  txqueuelen 1000  (以太网)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 58  bytes 9143 (9.1 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Then you can test the network connection using the ping command or telnet.

Next, run CDCNCM:

On NuttX, run:

$ conn 2
$ ifconfig
eth0    Link encap:Ethernet HWaddr 42:67:c6:69:73:51 at UP
        inet addr:10.0.1.2 DRaddr:10.0.1.1 Mask:255.255.255.0
eth1    Link encap:Ethernet HWaddr 00:e0:de:ad:be:ef at UP
        inet addr:0.0.0.0 DRaddr:0.0.0.0 Mask:0.0.0.0
$ dhcpd_start eth1
$ ifconfig
eth0    Link encap:Ethernet HWaddr 42:67:c6:69:73:51 at UP
        inet addr:10.0.1.2 DRaddr:10.0.1.1 Mask:255.255.255.0
eth1    Link encap:Ethernet HWaddr 00:e0:de:ad:be:ef at UP
        inet addr:10.0.0.1 DRaddr:10.0.0.1 Mask:255.255.255.0

On the host, you can see the network device named enx020000112233:

$ ifconfig
enx020000112233: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 576
        inet 10.0.0.2  netmask 255.255.255.0  broadcast 10.0.0.255
        ether 02:00:00:11:22:33  txqueuelen 1000  (以太网)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 58  bytes 9143 (9.1 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

Then you can test the network connection using the ping command or telnet.

Next, run CDCMBIM:

On NuttX, run:

$ conn 3
$ ifconfig
eth0    Link encap:Ethernet HWaddr 42:67:c6:69:73:51 at RUNNING mtu 1500
        inet addr:10.0.1.2 DRaddr:10.0.1.1 Mask:255.255.255.0
wwan0   Link encap:UNSPEC at RUNNING mtu 1200
        inet addr:0.0.0.0 DRaddr:0.0.0.0 Mask:0.0.0.0
$ ifconfig wwan0 10.0.0.1 netmask 255.255.255.0
$ ifconfig
eth0    Link encap:Ethernet HWaddr 42:67:c6:69:73:51 at RUNNING mtu 1500
        inet addr:10.0.1.2 DRaddr:10.0.1.1 Mask:255.255.255.0
wwan0   Link encap:UNSPEC at RUNNING mtu 1200
        inet addr:10.0.0.1 DRaddr:10.0.0.1 Mask:255.255.255.0

$ echo -n "hello from nuttx" > /dev/cdc-wdm2
$ cat /dev/cdc-wdm2
hello from linux

On the host, you can see the network device named wwx020000112233:

$ sudo ifconfig wwx020000112233
$ sudo ifconfig wwx020000112233 10.0.0.2 netmask 255.255.255.0
$ ifconfig
wwx020000112233: flags=4226<BROADCAST,NOARP,MULTICAST>  mtu 1500
        inet 10.0.0.2  netmask 255.255.255.0  broadcast 10.0.0.255
        ether 02:00:00:11:22:33  txqueuelen 1000  (以太网)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 58  bytes 9143 (9.1 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

$ sudo cat /dev/cdc-wdm1
hello from nuttx
$ sudo bash -c "echo -n hello from linux > /dev/cdc-wdm1"

Then you can test the network connection using the ping command or telnet.

usbhost

This is a configuration with sim usbhost support.

Libusb1.0 setup:

$ sudo apt-get -y install libusb-1.0-0-dev
$ sudo apt-get -y install libusb-1.0-0-dev:i386

Configuration

sim:usbhost supports CDCACM.

Configure the device you want to connect:
- CONFIG_SIM_USB_PID=0x0042
- CONFIG_SIM_USB_VID=0x1630
How to run

Run sim usbhost with root mode, run sim usbdev or plug-in cdcacm usb device. Then you can use /dev/ttyACM to transfer data.

login

This is a configuration with login password protection for NSH.

Note

This config has password protection enabled. The login info is:

USERNAME: admin
PASSWORD: Administrator

The encrypted password is retained in /etc/passwd. I am sure that you will find this annoying. You can disable the password protection by de-selecting CONFIG_NSH_CONSOLE_LOGIN=y.

can

This is a configuration with simulated CAN support. Both CAN character driver and SocketCAN are enabled and use the host vcan0 interface. The vcan0 host interface must be available when NuttX is started.

For the CAN character device, there is examples/can application enabled in read-only mode.

Additionally, SocketCAN candump and cansend utils are enabled.

Below is an example of receiving CAN frames from host to NuttX. Requirement: cansequence tool from linux-can/can-utils

Create virtual CAN on the host:

$ ip link add dev can0 type vcan
$ ifconfig can0 up

Run NuttX:
```
$ ./nuttx
```
Bring up can0 on NuttX:
```
nsh> ifup can0
ifup can0...OK
```
Read CAN messages from SocketCAN on NuttX:
```
nsh> candump can0
```
Send CAN messages from the host to NuttX:
```
$ cansequence can0
```

Frames from the host should be received on NuttX:

nsh> candump can0
can0  002   [1]  00
can0  002   [1]  01
can0  002   [1]  02
can0  002   [1]  03
can0  002   [1]  04
can0  002   [1]  05
can0  002   [1]  06
can0  002   [1]  07
can0  002   [1]  08
can0  002   [1]  09
can0  002   [1]  0A
can0  002   [1]  0B
can0  002   [1]  0C
can0  002   [1]  0D
can0  002   [1]  0E
can0  002   [1]  0F
can0  002   [1]  10
can0  002   [1]  11
can0  002   [1]  12

ROMFS System-Init

This directory contains logic to support a custom ROMFS system-init script and start-up script. These scripts are used by by the NSH when it starts provided that CONFIG_ETC_ROMFS=y. These scripts provide a ROMFS volume that will be mounted at /etc and will look like this at run-time:

NuttShell (NSH) NuttX-12.10.0
nsh> ls -Rl /etc
/etc:
 dr-xr-xr-x       0 .
 -r--r--r--      20 group
 dr-xr-xr-x       0 init.d/
 -r--r--r--      35 passwd
/etc/init.d:
 dr-xr-xr-x       0 ..
 -r--r--r--     110 rcS
 -r--r--r--     110 rc.sysinit
nsh>

/etc/init.d/rc.sysinit is system init script; /etc/init.d/rcS is the start-up script; /etc/passwd is a the password file. It supports a single user:

USERNAME:  admin
PASSWORD:  Administrator

nsh> cat /etc/passwd
admin:8Tv+Hbmr3pLVb5HHZgd26D:0:0:/

The encrypted passwords in the provided passwd file are only valid if the TEA key is set to: 012345678 9abcdef0 012345678 9abcdef0.

Changes to either the key or the password word will require regeneration of the nsh_romfimg.h header file.

The format of the password file is:

user:x:uid:gid:home

Where:

user: User name
x: Encrypted password
uid: User ID (0 for now)
gid: Group ID (0 for now)
home: Login directory (/ for now)

/etc/group is a group file. It is not currently used.

nsh> cat /etc/group
root:*:0:root,admin

The format of the group file is:

group:x:gid:users

Where:

group: The group name
x: Group password
gid: Group ID
users: A comma separated list of members of the group

Updating the ROMFS File System

The content on the nsh_romfsimg.h header file is generated from a sample directory structure. You can directly modify files under etc/ folder, The build system will regenerate nsh_romfsimg.h automatically.

See the sim:nsh configuration for an example of the use of this file system.

Replacing the Password File

The sim:nsh configuration can also be used to create a new password file.

First, make these configuration changes:

Disable logins

- CONFIG_NSH_CONSOLE_LOGIN=y
+ # CONFIG_NSH_CONSOLE_LOGIN is not set
  # CONFIG_NSH_TELNET_LOGIN is not set

Move the password file to a write-able file system:

- CONFIG_FSUTILS_PASSWD_PATH="/etc/passwd"
+ CONFIG_FSUTILS_PASSWD_PATH="/tmp/passwd"

Make the password file modifiable

- CONFIG_FSUTILS_PASSWD_READONLY=y
# CONFIG_FSUTILS_PASSWD_READONLY is not set

Now rebuild the simulation. No login should be required to enter the shell and you should find the useradd, userdel, and passwd commands available in the help summary, provided that they are enabled. Make certain that the useradd command is not disabled:

# CONFIG_NSH_DISABLE_USERADD is not set

Use the NSH useradd command to add new uses with new user passwords like:

nsh> useradd <username> <password>

Do this as many times as you would like. Each time that you do this a new entry with an encrypted password will be added to the passwd file at /tmp/passwd. You can see the passwd file like:

nsh> cat /tmp/passwd

When you are finished, you can simply copy the /tmp/passwd content from the cat command and paste it into an editor. Make sure to remove any carriage returns that may have ended up on the file if you are using Windows.

Then recreate the nsh_romfsimg.h file as described above. In step 2, simply replace the old /etc/passwd file with the one in your editor. When you are finished, the new passwd file will be in the ROMFS file system at the path /etc/passwd. When you restore the original NSH sim configuration, these are the passwords that will be used.