Application Programming
There are several language options available for writing application programs for EsduinoXtreme. One can use Assembler, C, or BASIC, or a combination of these. This section lists descriptions and hardware specific setup instructions for the various options available. The choice of what to use is left to the user. Generally, though, it will be based on application requirements, budget, and what the programmer is familiar with or willing to learn.
Keep in mind that there is a difference between a programming language and an Integrated Development Environment (IDE). An IDE combines several functions of the development process into one program. It can be designed to work with a specific language, like C or Forth. However the language does not define the IDE functionality. An IDE can include an editor, assembler, compiler, simulator, debugger, serial monitor interface or BDM pod interface, or some subset of these capabilities. It will depend upon the IDE. So review what each can do before choosing one to work with. An IDE can be useful because it can combine several development steps into one, or allow blending of the functions. (e.g. source-level debugging, or using both assembly and the featured language.)
To assist you in getting a better idea of what is available, here is a table of the major development platforms that are available, and that can be used to develop software for EsduinoXtreme:
| Language | Assembler | IDE | Terminal Program |
BDM Com | Other | |
| CodeWarrior Special | C | S12 | x | x |
free 32K limit for C unlimited assembler |
|
| CodeWarrior Pro | C | S12 | x | x |
commercial product | |
| HSW12 | Assembler | S12 | x | x | Linux |
|
| AsmIDE | Assembler | S12 | x | x | Windows | |
| MiniIDE | Assembler | asm12 | x | x | Windows |
|
| SBASIC | BASIC | as12 | DOS-based |
|||
| GCC-Syncode | C | as12 | Windows | |||
| GCC-Eclipse | C | as12 | Windows |
|||
| Imagecraft C | C | as12 | x |
x | some |
commercial product |
| Cosmic C | C | S12X | x | x | commercial product |
All of these will work with an assembler, and allow assembly code to be embedded within the language. The main difference will be in whch assembler is used. There are several S12 assemblers available that can be used to write software: Code Warrior from Freescale, Cosmic Software's cas12x (part of their C programming environment), and Dirk Heisswolf's HSW12. Each of these come with their own IDE programs as well.
What follows are brief descriptions, and instructions where needed, for each of these development tools.
CodeWarrior
CodeWarrior is considered the industry standard, and is available in different suites from Freescale. Each suite has different capabilities and prices. The least expensive of these is the Evaluation version, which is available for free. Its main limitation is that it only allows C programs to compile to a maximum size of 32 KB. The assembler is not bound by this limitation though. On the other end of the suites is the Professional version, which has no limitations. CodeWarrior includes an IDE and a simulator. You can find out more by visiting the Freescale site for CodeWarrior at:
Here is the link to download the Special Edition of the software. The link will download an executable to run that does the actual installation. You will also need to download and install the relevant Service Pack to support the S12GA240 MCU used on EsduinoXtreme, and the ReadMeFirst document. Please be aware that the file sizes are over 300 MB, so it is best to use the fastest network connection possible. Alternatively, you may order a CD from Freescale to obtain the software.
Here are some other links for documentation to help get CodeWarrior up and running. This is a comprehensive, and therefore complex, package. Plan to spend some time learning how to use it.
CodeWarrior Documentation List
Quick Start Instructions
Compiler Documentation
CodeWarrior Development Tools Learning Center
While CodeWarrior can be used to generate s19 files, it does not support direct interface through the on-chip serial monitor. uBug12 can perform that function by enabling you load the generated files into your board. However, if you'd like to use CodeWarrior for seamless loading and interactive debugging, you will need a BDM pod that is compatible with CodeWarrior. CodeWarrior is not guaranteed to work with all BDM pods, so be sure to see the list of compatible BDM pods in the Freescale documentation. The Technological Arts USBDMLT, which is a low-cost implementation of the open-source USBDM project, works very well and has the advantage of providing power to your board via the host USB port.
Dirk Heisswolf's HSW12
This S12X/XGATE assembler is part of Dirk Heisswolf's HSW12 IDE. This is a freeware IDE and assembler available on the web. (The site is listed in the instructions that follow.) The main difference between this development platform and others is that it is designed to be run on Linux systems. The IDE is also designed to work with a BDM pod when loading and debugging programs. However the assembler itself can easily be made to run on Windows computers, with the additional installation of a Perl interpreter, which is also freely available.
Here are the instructions to install Dirk Heisswolf's assembler on a Windows computer:
- Get the free ActiveState Perl executive installed. To do this, first go to the URL: http://www.activestate.com
- Under Community Tools, click on ActivePerl.
- On the next page that appears, click on the ActivePerl Download Now button.
- Choose to Save the file.
- After it is saved, then double click on the file to run it.
- You have to agree to the license to proceed.
- Standard settings work fine. Just click on Next each time it shows.
- The Perl interpreter is now installed on your computer.
- Get Dirk's freeware S12X assembler installed. To do this, go to his web site at: http://hotwolf.github.io/HSW12/hsw12asm.html
- Click on the Download link.
- Click on Save when prompted, and choose where to save the file.
- Once this file is saved, you will have to uncompress the archive. However, if you used IE to get the file, the file you get is also an archive! (If you use Firefox, you don't get this extra complication.)
- To uncompress this file, first rename it so it has a ‘.zip’ extension.
- Now decompress the zip archive.
- Take the folder that is created, called 'hsw12', and move it to the root directory of the C: drive.
To run the assembler, a DOS command window will have to be used. This can be done by going on your Windows system to the Start button, and clicking on Run under that. The command to run is 'cmd'. This will bring up a DOS window to type commands in. Here is an example of the command to run to use the assembler:
c:\Perl\bin\Perl.exe /hsw12/perl/hsw12asm.pl /MyProgram/Fconfig.asm -s19 -L /hsw12/perl
Note that there are no spaces used in the pathnames or filenames. If that was the case, that component would have to be enclosed in quotes. Complete pathnames have to be specified too for it to work. Therefore the command format used is cumbersome to type. To help make this process easier, an IDE like AsmIDE can be configured to do the command for us.
When using the HSW12 assembler, you will need to keep the following points in mind:
- The assembler likes code fields separated by the Tab character rather than by a space. This seems to be more an effect of using the ActiveState Perl interpreter than Dirk's assembler. Under certain circumstances, the assembler will flag a line as an error when the first character is a space rather than a tab, or when a space separate fields like label and instruction. I haven't spent time noting the exact circumstances of the effect. I just use tabs regardless now, and have not had a problem.
- Arithmetic expressions may have different rules of precedence than other assemblers. You need to specify parentheses for everything to make sure expressions get evaluated correctly. Evaluation seems to be right to left, whereas other assemblers may be left to right. The assembler is made to have the following precendence order: -/~, &, |, ^, >>, <<, *, /, %, +, -
- Comments after an instruction need to be prefixed by a semicolon, or they are considered part of the instruction. This also means that regardless of where a semicolon is in a line, it starts the comment section. Therefore the semicolon can't be part of of an instruction parameter like FCS ";CODE", where the programmer assumes the semicolon is supposed to be part of a string.
- If you need to use Indexed-indirect Program Counter Relative addressing, you will have to use the format [TARGET] for the instruction target address. Dirk does do offsets relative to the PC register, but uses this format to implement the PCR option seen in some other processor assemblers. So to do an indirect jump to an address held in memory location TARGET, the code will be: JMP [TARGET] ;Instruction is generated with offset relative to the PC register
- S2 records generated need to be checked carefully to make sure they are created to go into the correct place in memory. Using the ORG instruction can be tricky, and will produce bad results if not done correctly. Please read DIrk's comments on this thoroughly.
- The BRA instruction will change automatically to an LBRA instruction if the target address gets too far away. This is generally a good thing, but it does add two extra bytes to the code. So be aware of it if you end up needing to count bytes used by a routine. You can force the assembler not to switch to LBRA by prefixing the target address with the left angle bracket character "<".
- By default, the assembler assumes direct page addressing for addresses starting in $00xx. If you change the contents of the Direct Page register, you can let the assembler know about it with the SETDP directive. You can force direct addressing by prefixing the target address with the left angle bracket character "".
Once you have an S-record generated, you can program it into your module using the appropriate method for the hardware variant you are using (e.g. uBug12 for the Serial Monitor, or any compatible BDM pod).
AsmIDE
AsmIDE is not an assembler, but an IDE that comes with the default as12 assembler, and is capable of being adapted to using Dirk's HSW12 assembler, if desired. The install package for this IDE is available from several sites. The URLs are:
http://hcs12text.com/files/asmide340.zip
http://mamoru.tbreesama.googlepages.com/asmide340.zip
http://mamoru.tbreesama.googlepages.com/asmide-src.zip (This provides the source.)
To set this up to use the HSW12 assembler, you will first need to install the assembler and Perl interpreter as per the instructions previously provided in the HSW12 section. Next, download the AsmIDE zip file and extract the files into a directory created to contain them. You will find in your directory an executable called AsmIDE.exe.
Start the AsmIDE.exe program so that it can be configured. Once the application window appears:
- Go on the Menu bar to View > Options. This will bring up a dialog box that sets the IDE options.
- Select the Assembler tab at the top.
- You will need to change one of the default CPU settings. Under 'Currently Selected Chip family' select 6808. The recommended tab to pick is '6808 Options', as this is hardly used now.
- For 'Full pathname of Assembler', enter: c:\Perl\bin\Perl.exe
- For 'Full pathname of helpfile..', enter: C:\hsw12\doc\hsw12.html
- The last text box on the dialog is for assembler switches. This should have: hsw12asm.pl % -L /hsw12/perl/ -s19
- You will need to have your source code located where the Perl assembler is, at: C:\hsw12\perl
Now you can use the IDE to create assembler source files. They can be assembled by going to Build > Assemble on the IDE. This will generate a file of S-records that can be loaded into EsduinoXtreme.
MiniIDE
This is another IDE that comes with the asm12 assembler as its default. It is located at URL:
SBASIC
The SBASIC language is a 'no line numbers' variation of BASIC, with a compiler that runs on Windows computers. It uses the as12 assembler to generate object code,. You will need to download as12 and install it to use SBASIC. The URL for obtaining both SBASIC and the as12 code is:
http://www.seanet.com/~karllunt/sbasic.htm
Or if you prefer, here at the direct links:
SBASIC ZIP archive
as12 ZIP archive
Once this is extracted to its own directory, you will find within it the SBASIC compiler, called sbasic.exe. SBASIC is a compiler that runs via a command line. Use Start/Accessories/CommandPrompt in WIndows to open a DOS Command Prompt window. Typing the command without any parameters generates the following message, providing a summary of it's usage:
SBasic compiler (version 2.7) for the 68HC11/68HC12
usage: sbasic infile [options]
where infile is the name of an SBasic source file.
Input files have a .bas extension by default.
Output will be written to stdout.
Options are: /cxxxx /vxxxx /sxxxx /b /mxxxx /i
where xxxx is an address given as four hex digits.
/cxxxx sets first address of executable code
/vxxxx sets start of variables
/sxxxx sets top of return stack
/b generates branch opcodes, not jump opcodes
/mxxxx sets target MCU (6811 or 6812)
/i does not generate interrupt vector table
There are several sample programs included in the archive with SBASIC, along with a manual that explains its use in greater detail. You can pipe the output to a file that can be used by the assembler:
sbasic infile >outfile
You must specify options to have the program generate code that will work on the S12, as the default values will not work. Read the manual for more information on the options for variable location, stack, etc. that must be configured.
Once SBASIC generates an assembly file, you will need to use as12 to parse that file. It in turn will generate an S-record file that you can program into your target board. To start the as12 assembler, enter the following command at the prompt:
as12 file.ext
where file.ext is the path, name, and extension of the file you want to assemble, in this case the output saved from the sbasic command. The as12 assembler will assemble the file, sending the listing output to the console and writing the S19 object output to a file named m.out. You will want to then rename the m.out file to something ending in .s19 to load into the target system with uBug12 or a BDM pod.
Please note that SBASIC and as12 by themselves do not do any hardware setup. It is up to you to write the code to set up the MCU hardware.
SynCode and Eclipse GCC
The URL for these is:
Imagecraft C
Imagecraft C for CPU12 is a commercial product that supports HC(S)12 microcontrollers. It includes support for the NoICE12 debugger. You can download and use it for free during a 45 day trial period. There are special-priced versions for students and non-commercial users. The URL is:
Cosmic C Cross Development Environment
Cosmic C is a commercial product that includes the Cosmic S12 assembler and C compiler. They also have a full featured BDM source code debugger available, and full S12 simulator. Their IDE is called IDEA. It is available in versions for both Windows and Linux based computers. The URL is:
http://www.cosmic-software.com/s12x_des.php
