Hi,

looking at the embedded source code there has been done a lot of work. I'm interested in trying fpc on Cortex-M3 and M4, mostly from ST.

While trying to get an overview of the sources I found the declarations are pulled into a processor specific file by external declarations. But where does it come from, does the linker pull in the cmsis object files or something?

If so, how? There has to be a pointer to those files I couldn't find either.

Second question is:
Does the embedded target support hard floting point on STM32F4?

TIA,
Marc

CMSIS is a lot of things. What exact part of it are you asking about here?

FPC's embedded target has a bunch of controller units that are pulled in depending on the -Wp argument. These define exactly what you see in the units in the rtl/embedded/arm directory. In most cases just the physical registers, the interrupt vectors(and sometimes the IRQ levels), and some startup code. The mapping between the files and the controller names can be seen in the huge table in compiler/arm/cpuinfo.pas.

There are no object or source files for other parts of CMSIS, so things like the CMSIS-DSP and all cortex-m intrinsics don't work right now.

The cortexm3 and cortexm4 units that you can include in your uses clause will model some of the missing functionality but very far from all.

Floating point support is very untested. Most of it should work, but there might be some bugs. You can enable it by compiling your RTL and application with -CfFPv4_S16. If you decide to test it please write on the bugtracker if you run into problems.

Best Regards,
Jeppe

Jeppe Johansen wrote

CMSIS is a lot of things. What exact part of it are you asking about here?

In that file for example from line 887 on:

http://svn.freepascal.org/cgi-bin/viewvc.cgi/trunk/rtl/embedded/arm/stm32f407xx.pp?revision=32386&view=markup

there are lots of 'external'ly declared procedures. Where can I find them?

Have seen that, the wiki explains it.

Your older implementation of STM32F103 found on your website has declarations and implementations of the most important parts. The "new style" sources included in fpc/rtl haven't. Or at least I can't find them.

Floating point support is very untested. Most of it should work, but there might be some bugs. You can enable it by compiling your RTL and application with -CfFPv4_S16. If you decide to test it please write on the bugtracker if you run into problems.

I think I'll have to wait a while, that not the right toy for starting up. ;)

Thanks a lot!
Marc

Answering myself here:

Hmm, that's only a list of interrupt procedures. After the declaration there are some assembler seetings to have default values - OK, now I think I understand. It's up to the user to let them be set to default or redefine and implement the IRQ procedure.

No, it hasn't. I have read too many source files today. So there is only the declaration stuff for accessing the internals of the SoC, timers, peripherals and the like, OK.

Marc

Yes, you understand it correctly :)
The FPC RTL only exposes the hardware, not the firmware stack on top.

It might not be documented well anywhere but the weak linking with set defaults basically means you can declare interrupt handlers like this:

procedure MySystickHandler; [public, alias: 'SysTick_interrupt'];
begin
    // Code
end;

For STM32 there's the stm32f103fw file on my site. There's also a version on Anton Rieckert's github page which is split up a bit nicer. Not sure what the status or compatibility is.
Otherwise I can plug my project of converting the STM32F7 codebase here: https://github.com/Laksen/fp-stm32f7xx_hal

If anyone other know of any nice embedded projects/links be sure to chime in :)

I know some people have been working with Silicon Labs and Freescale codebases too. So there's a lot going on around.

Best Regards,
Jeppe

Chiming in ;-)

There are two more options:

https://github.com/yunkot/pxl

There are units available for higher level access to STM32F4, Teensy and some Freescale Devices. Very usable for devices that have >64k of Flash, a number of displays and sensors are supported out of the box.

When your board has Arduino compatible headers the code is very portable between the different devices.

https://github.com/yunkot/pxl/tree/PXL-cleanups

As there are some limitations with classes and memory usage in FreePascal there's a work-in-progress alternative available named MBF that uses record helpers.

Syntax and usage is 99% the same as with the PXL Library mentioned above but the memory footprint is much lower (typically 6-8k of flash for simple apps). Teensy/Freescale code is already there, I have not yet committed the STM32 and LPC8xx code as I wanted to commit them when they both on same feature level as the existing code. Also more examples will come with the new commit.

If you are interested in testing let me know...

Michael

I see. And there is no example in your testing code for stmf103fx.pas.

Since this should be documented somewhere:
Is that working for all embedded controller types? It should, the declarations look pretty much the same.

I'm willing to collect some informations for starters and make a wiki page out of it, but I'll have to ask a lot of questions first. ;)

On the wiki there is a lot of stuff, but what is missing a bit is a general getting started page for newbies.

My current targets are a f4-discovery board and maybe some simple f103 controllers not choosen yet. Besides that AVR would be nice to have. When that works maybe I'll be trying some SAM7S64 or S256 boards, too. In principle all of them would be handled identically, besides their intergrated peripherals.

So again:
The process of getting started would be the same on every simple controller? Simple means having no OS, only bare silicon.

What I know is:
- get biunutils
- build cross compiler
But that's all. Mostly simple testing programs are given, but not many explanations on declaring IRQ-handlers, loading up a binary, etc.

I like the technique of generating linker script and having memory address specifications and more build in the compiler. When using C and fiddling with Makefiles, linker scripts, not working code and so on can be very frustrating. And I like Pacal. ;)

What tools do you use to load the binary up to the embedded target?

Marc

Currently there is no support for embedded targets in the Lazarus Debugger so you will need to load/debug your code with the help of other tools.

For the Discovery board the easiest way to deploy binaries and to debug is to install openocd:

openocd -f board/stm32f4discovery.cfg

should connect you to the board, you can then use gdb (or cgdb or ddd) to upload and debug your code:

arm-none-eabi-gdb $BIN --eval-command="target extended :3333" --eval-command="set gdb_memory_map disable" --eval-command="monitor halt" --eval-command="set mem inaccessible-by-default off" --eval-command="load"

When you want to get a little more serious with the embedded target I'd highly recommend to buy a Segger J-Link Edu for about $50, it has support for almost any embedded controller on the market, for openocd the selection is a little more limited.

But the main advantage is that it comes with a very good gui based debugger, the JLinkDebugger allows you to load CMSIS svd files to directly browse all controller registers and it makes the whole debugging process a lot more convenient.

By the way, with fpc trunc compiler you can target your board directly:

ppcrossarm -WpDISCOVERYF407VG (see ppcrossarm -i for other Discovery boards)

You should also refrain from using optimizations > -O1 as there are some issues with the compiler that make your compiled binary unusable.

Michael

I have built the crosscompiler and the rtl for the STM32F429xx controller. Basic functions seem to work.

By default, the rtl is compiled with optimization -O2. Should the rtl be better compiled with optimization -O1 too, if there are issues with the compiler? Or is the rtl not affected?

What is recommended by the developers? Where bug reports accepted, if I use optimization -O2?

Regards, Bernd.

Good point, Jeppe, what do you think on compiling rtl on arm-embedded with -O1 ?

Michael

(Glad to hear that basic functionality works...)

By the way, I have done a patch for Lazarus so that debugging with ST-Link/JLink/Texane works, send me an e-mail when you want to test this.

Michael

Michael Ring wrote

(Glad to hear that basic functionality works...)

I finished my first (small) project with the STM32F429ZI controller and everything went smooth :-) Even with optimization level -O2.

Thanks everyone, who is involved in the ARM compiler/rtl development.

Regards, Bernd.

Did you use the stmf103fw.pas translation from Jeppe or make you own unit for supporting the 429?

My target would be f407, although the project in mind has to be done using an Atmel SAM7 now, programmed in C... :|

Marc Santhoff wrote

Did you use the stmf103fw.pas translation from Jeppe or make you own unit for supporting the 429?

I needed only a few peripherals (GPIO, USART, RCC and embedded FLASH). I wrote this stuff by myself.

My target would be f407, although the project in mind has to be done using an Atmel SAM7 now, programmed in C... :|

I used the AT91SAM7S256 controller 5 years ago (with fpc 2.3.1 btw). If I had to use ATMEL, I would look at the SAM3S or SAM4S family. They should replace the SAM7 which is now over 10 years old. But since ATMEL has been bought by Microchip, I would avoid them.

Regards, Bernd.

OK.

I know, I know. But it is a low volume device and the chips are in stock. Plus there is the complete compiler and support/HAL-library stuff already done.