A Real Time Operating System for the PIC – Epilog

 

Since writing these articles I have been tidying up the code and using it further for my own applications so I thought it would be a good idea to build a fresh version of the code and highlight some of the changes I have made since the first article was published.

 

Relative Addressing Option

 

Firstly, thanks to a little gem of advice from Tim I have reduced code size and more importantly reduced the overhead of the BRTOS considerably.  The complier has a directive SMALL_MICRO_MODEL = On/Off  When On, this directive instructs the compiler to use relative addressing for loops and branches etc rather than absolute addressing.  You have to be careful where you use it as if your loop is too long or you have a jump or branch outside the range of the relative address it will not work.  Whilst the compiler does not check for an out of range address the assembler does and it will report back the problem.

 

Try removing these directives and see what a difference it makes.

 

Note. Now you have the optimiser, the compiler will do it all for you OPTIMISER_LEVEL = 2 (Tim)

 

Serial Receive timer (RxTMR)

 

The RxTMR used to run as a 1 Hz task continuously, it now is only added when serial data is being received and is removed either on timeout or when a record has been processed.

 

Serial Out under Interrupts is now a Macro

 

I have changed the subroutine which copies the data string to the Serial Output buffer into a Macro command.  This makes it a little more like using the native HSerOut command although it only applies to data strings at present.  To use the Macro you simply write HISerOut StringArray where StringArray is the variable name of the string array you want to send to the serial port.

 

Adding Macros to the IDE Parameter Hints

 

To make it a really professional job you can add parameter hints for your macro’s.  These are contained in a text file called USER.MCD.  I have added hints for all the Macros used in BRTOS.  To install them copy the attached USER.MCD to your ProtonIDE directory, then restart the IDE.  (Note – if you have already produced macro’s of your own and have created your own USER.MCD either add this file to your file or swap it after saving your original).

 

Menu Operation

 

I have changed the way the menu code works slightly to make it more uniform.  The change involves including the default display (i.e. menu off) mode within the menu structure.  The menus behave exactly the same as they always did but now you return to the default display via the same jump table as all the other menu entries.

 

Optimisation

 

I have broken the day of week calculation in the RTC file down into separate elements.  Whilst this makes the Basic code longer it reduces the code produced by over 100 bytes.  In fact I have been through much of the other code and wherever possible tried to reduce each line to simple commands reducing the Inline commands to a minimum.  Its amazing how much code you can save doing this.

 

ADDImmd, ADDTask, REMTask, REPTask, POSTask macros have been optimized.  They do not now pass the parameter via the stack but now place them directly in the required variables.  This saves pushing and popping Byte and Word variables every time they are called.

 

Bugs

 

I have corrected a bug in Task Manager.  If you changed the task list from within a task and the task rate of the task you changed was different from the current active task any tasks at the same rate of the current task would not get executed.  It sounds very subtle but extremely confusing if you stumble across it.  I could have just left it and put a restriction on not changing tasks from within a task but it only required a Push and a Pop to solve it.

 

BRTOS Task Monitor

 

I have attempted to make the comms more rugged so that it will recover from more error situations rather than leaving you stranded.  It is still not perfect but as this is a tool for development I think it is adequate under most situations.

 

I have also changed the way the Options dialog works when setting up network addresses and port numbers – hopefully it’s a little more intuitive.

 

Finally sorted the situation where task monitor was started by the IDE and the IDE closed before Task Monitor was closed.

 

 

 

Attached Files

 

The attached files comprise the whole package:

 

BRTOS_Clock_Demo.zip is the Proton source for all BRTOS as described.

 

BRTOS_Task_Monitor_VB_Install.zip is the installation program for the VB DLLs required – it does not include the application just the support files.

 

BRTOS_Task_Manager_PluginInstall.exe will install the BRTOS Task Monitor application in the IDE plug in directory under JGBTools.

 

Run the VB install first to install the VB support components then run the Plugin Install program.

 

To see the task monitor, run the IDE, click on the Plugin icon and select JGBTools, BRTOS Task Monitor.

 

user.mcd replace this file to get highlighting and context help on the macros unless you are using the file already in which case copy the contents in your existing copy.

 

 

Have fun

 

JohnB