freeRTOS and ATmega16

Kernel
1

nobody wrote on Thursday, November 11, 2004:

I’m trying to use freeRTOS with ATmega!^ could you please tell me what changes should i do in order to work wiht freeRTOS that refers on ATmega323?

2

rtel wrote on Thursday, November 11, 2004:

See the "To use a microcontroller other than an AVR ATMega323" section of the AVR port documentation.

The part about the tick timer having a different configuration is relevant to the Mega16.

The Mega16 has half the memory of the 323, which means it cannot run all the tasks in th demo application.  If you wish to use an OS maybe external RAM would be preferable as the 16 only has 1K.

Regards.

3

nobody wrote on Thursday, November 11, 2004:

If i dont want to use an external RAM,what changes should i do in the source code in order to use ATmega16

4

rtel wrote on Friday, November 12, 2004:

Assuming you have already looked at the "To use a microcontroller other than an AVR ATMega323" section of http://www.freertos.org/a00098.html  - and followed the instructions there - then in addition to use a part with only 1K of RAM you will have to create less tasks.

To just run the flash tasks (assuming you have an STK500):

1) Remove the lines in demo/ATMega323/main.c that create tasks, other than the flash tasks…so delete the lines :

vStartIntegerMathTasks( tskIDLE_PRIORITY );
vAltStartComTestTasks( mainCOM_TEST_PRIORITY, mainCOM_TEST_BAUD_RATE, mainCOM_TEST_LED );
vStartPolledQueueTasks( mainQUEUE_POLL_PRIORITY );
and
sTaskCreate( vErrorChecks, "Check", portMINIMAL_STACK_SIZE, NULL, mainCHECK_TASK_PRIORITY, NULL );

I tried this in the AVRStudio simulator with portTOTAL_HEAP_SIZE set to 700.

As stated previously, I think the timer setup is slightly different on the 16 than the 323 - so this will require modification in port.c.

5

nobody wrote on Friday, November 12, 2004:

Thank you i 'll try this. ( I use STK500)

Nick Pol.

6

nobody wrote on Sunday, November 14, 2004:

when i try to simulate the hex file it appears this message

Objectfile does not exist: D:\Documents and Settings\nikos\FreeRTOSV2.5.2\Demo\ATMega323\coff\rtosdemo.hex

does anyone know what is the problem?

thanks N. Pol

7

nobody wrote on Sunday, November 14, 2004:

Run buildclean.bat, then buildcof.bat and check that the build completes successfully.

Then start AVR studio and open rtosdemo.cof (i.e. not hex) from the created coff directory.