embed
=====
This example illustrates a simple C program, suitable for embedded
applications.
The main C program is contained in main.c. This has a main() function, which
calls subroutines to show the use of printf(), sprintf(), floating point
printf() and malloc(). This can be compiled/linked on its own and executed
in the semihosting environment (see build a below). Alternatively, the project
can be built as an embedded application with no semihosting (builds b & c).
This example can be built in three different ways, in increasing order of
complexity:
a. Non-embedded (semihosted), scatterloaded
b. Embedded, with ROM fixed at 0x0, scatterloaded
c. Embedded, ROM/RAM remapped, scatterloaded
For options b and c, all hard coded addresses are located in the scatterfile
To build the example, either:
- use the supplied batch files (build_a.bat, build_b.bat, build_c.bat), or
- use the supplied CodeWarrior project file (embed.mcp, with 3 targets:
Semihosted, EmbeddedScatter, EmbeddedScatterRemap), or
- create your own make files.
These create an ELF image (embed.axf) suitable for loading into an ARM
debugger. A Motorola32 ROM image (embed.m32) is also created, suitable
for loading into a target, for example, downloading into the flash memory
of an ARM Integrator board.
To convert it into an embeddable application, additional files are provided:
1. vectors.s contains exception vectors and exception handlers. Where there
is ROM fixed at 0x0 (build_b), these are hard-coded at 0x0.
Where ROM/RAM remapping occurs (build_c), these are copied from ROM to
RAM.
2. init.s performs ROM/RAM remapping (if required), initializes stack
pointers and interrupts for each mode, and finally branches to __main
in the C library (which eventually calls main()).
3. retarget.c implements a 'retarget' layer for low-level I/O. Typically,
this would contain your own target-dependent implementations of
fputc(), ferror(), etc. This example provides implementations of
fputc(), ferror(), _sys_exit(), _ttywrch() and
__user_initial_stackheap(). Here, semihosting SWIs are used to
display text onto the console of the host debugger. This mechanism is
portable across ARMulator, Angel and Multi-ICE.
Alternatively, to output characters from the serial port of an ARM
Integrator Board (see serial.c), use '#define USE_SERIAL_PORT' or
compile with '-DUSE_SERIAL_PORT'.
4. serial.c implements a simple (polled) RS232 serial driver for the ARM
Integrator Board. It outputs single characters on Serial
Port A at 38400 Baud, 8 bit, no parity, 1 stop bit. To monitor the
characters output, use a null-modem cable to connect Serial Port A to
an RS232 terminal or PC running a terminal emulator, e.g. HyperTerminal.
5. In addition the files stack.s and heap.s are used to create dummy variables
which are placed in memory by the scatter load file. These can then be used
to place the stack and heap respectively.
6. Finally uart.c instantiates a struction corresponding to the layout of
the uart registers. This structure is located in memory by the scatter load
file.
To ensure that no functions which use semihosting SWIs are linked in from the
C library, __use_no_semihosting_swi is used for the 2 'embeddable' builds.
The 3 different builds can be executed either on the ARMulator, or on real
hardware (e.g. Integrator board via Multi-ICE). To run the examples on real
hardware, please note:
i. For Semihosted (build_a) build targets, set $top_of_memory to a suitable
value via the debugger. The (unexpanded) Integrator CM has 256KB of SSRAM
fitted, so set $top_of_memory=0x40000. If additional SDRAM is fitted, set
$top_of_memory appropriately. It is not necessary to set $top_of_memory for
the other builds, because they implement __user_initial_stackheap().
ii. For EmbeddedScatter (build_b.bat) and EmbeddedScatterRemap (build_c.bat)
build targets, set $vector_catch=0 to prevent exceptions being caught, and to
free up a watchpoint unit in the EmbeddedICE Logic.
iii. EmbeddedScatterRemap (build_c.bat) is intended to be downloaded into Flash
(see below).
Building for Thumb
------------------
The supplied batch files (build_a.bat, build_b.bat, build_c.bat) and supplied
CodeWarrior project files build ARM-only versions of this code.
To build ARM/Thumb interworking versions of this example, where the bulk
of the C code is compiled for Thumb, change the invocations of 'armcc'
into 'tcc -apcs /interwork', so that e.g. build_c.bat becomes:
armasm -g vectors.s
armasm -g -PD "ROM_RAM_REMAP SETL {TRUE}" init.s
armasm -g stack.s
armasm -g heap.s
REM Use the following two lines to build without using the serial port.
tcc -apcs /interwork -c -g -O1 main.c -DEMBEDDED -DROM_RAM_REMAP
tcc -apcs /interwork -c -g -O1 retarget.c
REM Use the following two lines to build using the serial port.
REM tcc -apcs /interwork -c -g -O1 main.c -DEMBEDDED -DROM_RAM_REMAP -DUSE_SERIAL_PORT
REM tcc -apcs /interwork -c -g -O1 retarget.c -DUSE_SERIAL_PORT
tcc -apcs /interwork -c -g -O1 uart.c -I..\include
tcc -apcs /interwork -c -g -O1 serial.c -I..\include
armlink vectors.o init.o main.o retarget.o uart.o serial.o stack.o heap.o -scatter scat_c.scf -o embed.axf -entry 0x24000000 -info totals -info unused
fromelf embed.axf -bin -o embed.bin
fromelf embed.axf -m32 -o embed.m32
Downloading to Flash
--------------------
Follow the instrictions below to download the 'Embedded, scatterloaded'
examples 'build_b' and 'build_c' to the flash memory of an ARM Integrator
board, so that you can execute/debug the image at source level.
Use the debugger's File->Flash-download feature, which uses flash.li/.bi.
This requires a plain binary image to be built with:
fromelf embed.axf -bin -o embed.bin
See 'AXD and armsd Debuggers Guide', Appendix D, "Using the Flash Downloader".
Alternatively:
Follow the steps 1-8 below to download using the Integrator's Boot Loader:
These steps require a terminal emulator such as 'HyperTerminal'.
1. Connect the Integrator board to the host computer using a null modem
serial cable.
2. Invoke the terminal emulator and ensure it has the following settings:
- Baud rate 38400
- Data bits 8
- No parity
- Stop bits 1
- Flow control Xon/Xoff
3. Ensure switches 1 and 4 on the Integrator board are in the 'ON'
position and reset the board.
4. Enter 'l' to load flash image at the Boot Loader prompt in the terminal
window.
5. Transfer the 'embed.m32' file via the serial cable using the terminal
tools. In Hyperterminal this is done by selecting
'Transfer->Send Text File' from the menu and navigating to the
embed.m32 file.
6. Once the image has loaded (approx 25 seconds) terminate the flash
transfer by pressing Ctrl-C.
7. Ensure switch 1 is returned to the 'OFF' position.
8. The image is now present in flash and will be executed when the board
is reset. Output from the image will be sent to the terminal window
only if the image was built using the -USE_SERIAL_PORT option.
Otherwise output must be viewed using AXD with the image debug
symbols via a connection to the board such as Multi-Ice.
Memory Maps
-----------
The following diagrams illustrate the Memory Maps for this example, for each
different build:
build_a.bat:
0x08000000 (ARMulator) or
+----------+ 0x00040000 (Integrator board)
| stack |
| VV |
~ ~
| ^^ |
| heap |
+----------+ Image$$ZI$$Limit
| ZI data |
+----------+
| RW data |
+----------+
| |
| |
| program |
| (RO+RW) |
| |
| |
+----------+ 0x8000
build_b.bat
--- +----------+ 0x280800
ucos运行原理剖析系列博客文章之资源2 （431个子文件） 
libc.a 20KB libc.a 20KB libc.a 20KB libc.a 20KB Exp10.axf 239KB Exp10.axf 217KB winix.backup 12KB head.S.backup 3KB system.bin 37KB system.bin 30KB os_core.c 67KB os_flag.c 53KB os_task.c 49KB os_q.c 36KB os_mutex.c 29KB os_mbox.c 25KB os_sem.c 23KB vsprintf.c 18KB vsprintf.c 18KB os_mem.c 18KB os_time.c 11KB string.c 10KB string.c 10KB os_dbg.c 10KB serial-2410.c 9KB isr.c 8KB lib.c 7KB os_cpu_c.c 7KB retarget.c 6KB init.c 6KB mmu.c 5KB init.c 5KB sched.c 5KB UHAL.c 4KB mmu.c 4KB mmu.c 4KB init.c 4KB main.c 4KB init.c 3KB init.c 3KB init.c 3KB init.c 3KB Uart.c 3KB init.c 3KB muldi3.c 3KB muldi3.c 3KB init.c 3KB init.c 2KB cpu.c 2KB drivers.c 2KB OSAddTask.c 2KB ctype.c 1KB ctype.c 1KB main.c 990B interrupt.c 974B main.c 918B key_led.c 867B printf.c 867B printf.c 867B serial.c 706B serial.c 702B serial.c 702B main.c 688B serial.c 670B serial.c 621B serial.c 621B main.c 619B main.c 619B main.c 618B leds.c 558B interrupt.c 558B interrupt.c 558B interrupt.c 558B string.c 555B serial.c 514B main.c 468B main.c 468B leds.c 466B sdram.c 464B main.c 374B main.c 366B interrupt.c 188B interrupt.c 188B led_on_c.c 186B main.c 55B #string.c# 582B cat_sh 116B clock 3KB crt0 24B init.c~ 6KB mmu.c~ 5KB init.c~ 3KB serial.c~ 670B vsprintf.d 326B vsprintf.d 302B string.d 214B string.d 198B main.d 192B printf.d 148B printf.d 140B共 431 条
- 1
- 2
- 3
- 4
- 5
- 1
- 2
前往页