README.txt
==========
This README file discusses the port of NuttX to the WaveShare Open1788 board:
See http://wvshare.com/product/Open1788-Standard.htm. This board features the
NXP LPC1788 MCU
CONTENTS
========
o LEDs
o Buttons
o FPU
o Using OpenOCD with the Olimex ARM-USB-OCD
o Configuration
LEDs
====
The Open1788 base board has four user LEDs
LED1 : Connected to P1[14]
LED2 : Connected to P0[16]
LED3 : Connected to P1[13]
LED4 : Connected to P4[27]
If CONFIG_ARCH_LEDS is not defined, then the user can control the LEDs in
any way using the defitions provided in the board.h header file.
If CONFIG_ARCH_LEDs is defined, then NuttX will control the 3 LEDs on the
WaveShare Open1788K. The following definitions describe how NuttX controls
the LEDs:
LED1 LED2 LED3 LED4
LED_STARTED OFF OFF OFF OFF
LED_HEAPALLOCATE ON OFF OFF OFF
LED_IRQSENABLED OFF ON OFF OFF
LED_STACKCREATED ON ON OFF OFF
LED_INIRQ LED3 glows, on while in interupt
LED_SIGNAL LED3 glows, on while in signal handler
LED_ASSERTION LED3 glows, on while in assertion
LED_PANIC LED3 Flashes at 2Hz
LED_IDLE LED glows, ON while sleeping
Buttons
=======
The Open1788K supports several buttons:
USER1 : Connected to P4[26]
USER2 : Connected to P2[22]
USER3 : Connected to P0[10]
And a Joystick
JOY_A : Connected to P2[25]
JOY_B : Connected to P2[26]
JOY_C : Connected to P2[23]
JOY_D : Connected to P2[19]
JOY_CTR : Connected to P0[14]
These can be accessed using the definitions and interfaces defined in the
board.h header file.
FPU
===
FPU Configuration Options
-------------------------
There are two version of the FPU support built into the LPC17xx port.
1. Lazy Floating Point Register Save.
This is an untested implementation that saves and restores FPU registers
only on context switches. This means: (1) floating point registers are
not stored on each context switch and, hence, possibly better interrupt
performance. But, (2) since floating point registers are not saved,
you cannot use floating point operations within interrupt handlers.
This logic can be enabled by simply adding the following to your .config
file:
CONFIG_ARCH_FPU=y
2. Non-Lazy Floating Point Register Save
Mike Smith has contributed an extensive re-write of the ARMv7-M exception
handling logic. This includes verified support for the FPU. These changes
have not yet been incorporated into the mainline and are still considered
experimental. These FPU logic can be enabled with:
CONFIG_ARCH_FPU=y
CONFIG_ARMV7M_CMNVECTOR=y
You will probably also changes to the ld.script in if this option is selected.
This should work:
-ENTRY(_stext)
+ENTRY(__start) /* Treat __start as the anchor for dead code stripping */
+EXTERN(_vectors) /* Force the vectors to be included in the output */
CFLAGS
------
Only the Atollic toolchain has built-in support for the Cortex-M4 FPU. You will see
the following lines in each Make.defs file:
ifeq ($(CONFIG_STM32_ATOLLIC_LITE),y)
# Atollic toolchain under Windows
...
ifeq ($(CONFIG_ARCH_FPU),y)
ARCHCPUFLAGS = -mcpu=cortex-m4 -mthumb -march=armv7e-m -mfpu=fpv4-sp-d16 -mfloat-abi=hard
else
ARCHCPUFLAGS = -mcpu=cortex-m3 -mthumb -mfloat-abi=soft
endif
endif
If you are using a toolchain other than the Atollic toolchain, then to use the FPU
you will also have to modify the CFLAGS to enable compiler support for the ARMv7-M
FPU. As of this writing, there are not many GCC toolchains that will support the
ARMv7-M FPU.
As a minimum you will need to add CFLAG options to (1) enable hardware floating point
code generation, and to (2) select the FPU implementation. You might try the same
options as used with the Atollic toolchain in the Make.defs file:
ARCHCPUFLAGS = -mcpu=cortex-m4 -mthumb -march=armv7e-m -mfpu=fpv4-sp-d16 -mfloat-abi=hard
Configuration Changes
---------------------
Below are all of the configuration changes that I had to make to configs/stm3240g-eval/nsh2
in order to successfully build NuttX using the Atollic toolchain WITH FPU support:
-CONFIG_ARCH_FPU=n : Enable FPU support
+CONFIG_ARCH_FPU=y
-CONFIG_STM32_CODESOURCERYW=y : Disable the CodeSourcery toolchain
+CONFIG_STM32_CODESOURCERYW=n
-CONFIG_STM32_ATOLLIC_LITE=n : Enable *one* the Atollic toolchains
CONFIG_STM32_ATOLLIC_PRO=n
-CONFIG_STM32_ATOLLIC_LITE=y : The "Lite" version
CONFIG_STM32_ATOLLIC_PRO=n : The "Pro" version
-CONFIG_INTELHEX_BINARY=y : Suppress generation FLASH download formats
+CONFIG_INTELHEX_BINARY=n : (Only necessary with the "Lite" version)
-CONFIG_HAVE_CXX=y : Suppress generation of C++ code
+CONFIG_HAVE_CXX=n : (Only necessary with the "Lite" version)
See the section above on Toolchains, NOTE 2, for explanations for some of
the configuration settings. Some of the usual settings are just not supported
by the "Lite" version of the Atollic toolchain.
Using OpenOCD with the Olimex ARM-USB-OCD
=========================================
Building OpenOCD under Cygwin:
Refer to configs/olimex-lpc1766stk/README.txt
Installing OpenOCD in Ubuntu Linux:
sudo apt-get install openocd
Helper Scripts.
I have been using the Olimex ARM-USB-OCD debugger. OpenOCD
requires a configuration file. I keep the one I used last here:
configs/open1788/tools/open1788.cfg
However, the "correct" configuration script to use with OpenOCD may
change as the features of OpenOCD evolve. So you should at least
compare that open1788.cfg file with configuration files in
/usr/share/openocd/scripts. As of this writing, the configuration
files of interest were:
/usr/local/share/openocd/scripts/interface/openocd-usb.cfg
This is the configuration file for the Olimex ARM-USB-OCD
debugger. Select a different file if you are using some
other debugger supported by OpenOCD.
/usr/local/share/openocd/scripts/board/?
I don't see a board configuration file for the WaveShare
Open1788 board.
/usr/local/share/openocd/scripts/target/lpc1788.cfg
This is the configuration file for the the LPC1788 target.
It just sets up a few parameters then sources lpc17xx.cfg
/usr/local/share/openocd/scripts/target/lpc17xx.cfg
This is the generic LPC configuration for the LPC17xx
family. It is included by lpc1788.cfg.
NOTE: These files could also be located under /usr/share in some
installations. They could be most anywhwere if you are using a
windows version of OpenOCD.
configs/open1788/tools/open1788.cfg
This is simply openocd-usb.cfg, lpc1788.cfg, and lpc17xx.cfg
concatenated into one file for convenience. Don't use it
unless you have to.
There is also a script on the tools/ directory that I use to start
the OpenOCD daemon on my system called oocd.sh. That script will
probably require some modifications to work in another environment:
- Possibly the value of OPENOCD_PATH and TARGET_PATH
- It assumes that the correct script to use is the one at
configs/open1788/tools/open1788.cfg
Starting OpenOCD
Then you should be able to start the OpenOCD daemon as follows. This
assumes that you have already CD'ed to the NuttX build directory:
. ./setenv.sh
oocd.sh $PWD
The setenv.sh script is a convenience script that you may choose to
use or not. It simply sets up the PATH variable so that you can
automatically find oocd.sh. You could also do:
configs/open1788/tools/oocd.sh $PWD
Connecting GDB
Once the OpenOCD daemon has been started, you can connect to it via
GDB using the following GDB command:
arm-nuttx-elf-gdb
(gdb) target remote localhost:3333
NOTE: The name of your GDB program may differ. For example, with the
CodeSourcery toolchain, the ARM GDB would be called arm-none-eabi-gdb.
OpenOCD will support several special 'monitor' sub-commands. You can
use the 'monitor' (or simply 'mon') command to invoke these sub-
commands. These GDB commands will send comments to the OpenOCD monitor.
Here are a couple that you will need to use:
(gdb) monitor reset
(gdb) monitor halt
NOTES:
1. The MCU must be halted using 'monitor halt' prior to loading code.
2. 'monitor reset' will restart the processor after loading code.
3. The 'monitor' command can be abbreviated as just 'mon'.
After starting GDB, you can load the NuttX ELF file:
(gdb) mon halt
(gdb) load nuttx
NOTES:
1. NuttX should have been built so that it has debugging symbols
(by setting CONFIG_DEBUG_SYMBOLS=y in the .config file).
2. The MCU must be halted prior to loading code.
3. I find that there are often undetected write failures. I usually
load nuttx twice to assure good FLASH contents:
(gdb) mon halt
(gdb) load nuttx
(gdb) mon reset
(gdb) mon halt
(gdb) load nuttx
CONFIGURATION
=============
ostest
------
This configuration directory, performs a simple OS test using
apps/examples/ostest.
NOTES:
1. This configuration uses the mconf-based configuration tool. To
change this configuration using that tool, you should:
a. Build and install the kconfig-mconf tool. See nuttx/README.txt
and misc/tools/
b. Execute 'make menuconfig' in nuttx/ in order to start the
reconfiguration process.
2. Uses the older, OABI, buildroot toolchain. But that is easily
reconfigured:
CONFIG_ARMV7M_TOOLCHAIN_BUILDROOT=y : Buildroot toolchain
CONFIG_ARMV7M_OABI_TOOLCHAIN=y : Older, OABI toolchain
knsh
----
This is identical to the nsh configuration below except that NuttX
is built as a kernel-mode, monolithic module and the user applications
are built separately. It is recommends to use a special make command;
not just 'make' but make with the following two arguments:
make pass1 pass2
In the normal case (just 'make'), make will attempt to build both user-
and kernel-mode blobs more or less interleaved. This actual works!
However, for me it is very confusing so I prefer the above make command:
Make the user-space binaries first (pass1), then make the the kernel-space
binaries (pass2)
There are ordering dependencies so, for example, 'make -j 6' fails.
'make -j 6 pass1 pass2' does work fine, however.
NOTES:
1. This configuration uses the mconf-based configuration tool. To
change this configuration using that tool, you should:
a. Build and install the kconfig-mconf tool. See nuttx/README.txt
and misc/tools/
b. Execute 'make menuconfig' in nuttx/ in order to start the
reconfiguration process.
2. Uses the older, OABI, buildroot toolchain. But that is easily
reconfigured:
CONFIG_ARMV7M_TOOLCHAIN_BUILDROOT=y : Buildroot toolchain
CONFIG_ARMV7M_OABI_TOOLCHAIN=y : Older, OABI toolchain
3. At the end of the build, there will be several files in the top-level
NuttX build directory:
PASS1:
nuttx_user.elf - The pass1 user-space ELF file
nuttx_user.hex - The pass1 Intel HEX format file (selected in defconfig)
User.map - Symbols in the user-space ELF file
PASS2:
nuttx - The pass2 kernel-space ELF file
nuttx.hex - The pass2 Intel HEX file (selected in defconfig)
System.map - Symbols in the kernel-space ELF file
Loading these .elf files with OpenOCD is tricky. It appears to me
that when nuttx_user.elf is loaded, it destroys the the nuttx image
in FLASH. But loading the nuttx ELF does not harm the nuttx_user.elf
in FLASH. Conclusion: Always load nuttx_user.elf before nuttx.
Just to complicate matters, it is sometimes the case that you need
load objects twice to account for write failures. I have not yet
found a simple foolproof way to reliably get the code into FLASH.
nsh
---
Configures the NuttShell (nsh) located at examples/nsh. The
Configuration enables both the serial NSH interface.
NOTES:
1. This configuration uses the mconf-based configuration tool. To
change this configuration using that tool, you should:
a. Build and install the kconfig-mconf tool. See nuttx/README.txt
and misc/tools//README.txt.
b. Execute 'make menuconfig' in nuttx/ in order to start the
reconfiguration process.
2. Uses the older, OABI, buildroot toolchain. But that is easily
reconfigured:
CONFIG_ARMV7M_TOOLCHAIN_BUILDROOT=y : Buildroot toolchain
CONFIG_ARMV7M_OABI_TOOLCHAIN=y : Older, OABI toolchain
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