FreeDOS provides a convenient, reliable and royalty free boot system, along with file and console IO. The usual 16bit DOS restrictions apply, a little wasteful on a Pentium system!
See the FAQ "Will FreeRTOS run under Windows" for information on how this port can be tested from a Windows DOS box.
FreeDOS
provides a convenient, reliable and royalty free boot system, along with file and console IO. The usual 16bit DOS
restrictions apply, a little wasteful on a Pentium system!
If your chosen target single board computer includes a network adapter then freely available packet drivers can be used to map a drive from your host system onto your target. The application under development can then be executed and debugged from the mapped drive - removing the requirement to download the application after each compilation.
The PC compatible architecture allows the use of the Open Watcom development tools both directly on the target single board computer should space allow, or via the remote debugging utilities. Although not open source, the Borland development tools have also proved reliable.
From V4.0.0 the PC demo has been updated to demonstrate the use of co-routines. See the co-routine documentation page for more information.
See also the FAQ My application does not run, what could be wrong?
The FreeRTOS download contains the source code for all the FreeRTOS ports.
See the Source Code Organization section for a description of the downloaded files and information on creating a new project.
The PC target project files (Open Watcom and Borland) are contained in the Demo/PC directory.
The demo application utilises the standard parallel port to control 8 LEDs. Omitting these LEDs will not cause the RTOS demo application to fail, but will remove some visual feedback that everything is working as expected.
The RTOS kernel does not maintain the context of the floating point registers. When using Open Watcom, the NO87 environment variable must be defined to force the use of floating point emulation.
The Borland floating point emulation is not re-entrant - but tricks for making it so are quite well documented.
The LEDs connected to the parallel port are under control of the 'flash' co-routines. Each will flash at a constant but different frequency as described in the demo application documentation. Each LED is controlled by a different co-routine.
A check task is included that monitors all the real time tasks and co-routines. An error occurring in any task or co-routine will wake the 'Check' task and cause an error message to be output to the display. In addition, every five seconds the 'Check' task examines all the tasks in the system to ensure they are executing without error then outputs a status message. An 'OK' status message indicates that no errors have been detected. This mechanism can be checked by removing the loopback connector from the serial port (described above), and in doing so deliberately generating an error.
Each port #defines 'BaseType_t' to equal the most efficient data type for that processor. This port defines BaseType_t to be of type short.