OSA : Memory usage

These tables allow you to predict average ROM and RAM usage so that you can choose an appropriate microcontroller for your project.

* - see Note 4 below

Test modes:

1. min (minimal services set)
   • priorities are OFF
   • allowed: binary semaphores, flags, messages
2. normal (most usual services set)
   • priorities are ON
   • task timers are enabled
   • allowed: binary semaphores, flags, messages
   • waiting with exit on timeout services are enabled
3. full (full services set, except user timers)
   • priorities are ON
   • task timers are enabled
   • allowed: binary semaphores, counting semaphores, flags, messages, queues
   • waiting with exit on timeout services are enabled
   • critical sections enabled

(All modes support services for switching context, waiting for events, controlling tasks, enabling/disabling interrupts)

Notes:

1. ROM results:
   • size of ROM shown in machine words for PIC10, PIC12 and PIC16 and in bytes for other;
   • for MCC18 initialization code is included;
   • for MCC30 initialization code is included;
2. all test were compiled with maximum optimization;
3. in addition OSA requares RAM for task deskriptors;
4. there is a base size of descriptor in table. It can be greater if:
   • task timer used (OS_ENABLE_TTIMER) - by OS_TTIMER_SIZE bytes (default 2);
   • chips with ROM > 64K requires another 2 bytes per task for saving higher addresses;
   • when using OS_PRIORITY_EXTENDED mode, each task requires another 2 bytes;
5. memory usage can be reduced by disabling priority and by using one byte timers (see OSAcfg.h).