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.
| min, ROM/RAM | normal, ROM/RAM | full, ROM/RAM | Bytes per task*, RAM | |
|---|---|---|---|---|
| PIC10 (PIC12) |
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| Hi-tech PICC | 153 / 11 | 250 / 14 | 363 / 14 | 2 |
| PIC16 (PIC12) |
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| HT-PICC STD | 152 / 8 | 258 / 11 | 396 / 13 | 3 |
| HT-PICC PRO (PIC1xF1xxx) | 169 / 6 | 291 / 10 | 385 / 10 | 3 |
| microC PRO | 180 / 14 | 307 / 17 | 474 / 17 | 3 |
| CCS PICC | 254 / .. | 399 / .. | 573 / .. | 3 |
| PIC18 |
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| HT-PICC18 STD | 336 / 7 | 548 / 10 | 982 / 16 | 3 |
| MPLAB C18 | 598 / 7 | 862 / 10 | 1214 / 16 | 4 |
| microC PRO | 426 / 11 | 746 / 16 | 1136 / 17 | 3 |
| CCS PICC | 436 / .. | 696 / .. | 1046 / .. | 3 |
| PIC24 (dsPIC) |
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| MPLAB C30 | 846 / 10 | 1065 / 16 | 1305 / 16 | 20 |
| AVR |
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| WinAVR | 602 / 8 | 1030 / 13 | 1348 / 15 | 10 |
| IAR | 550 / 8 | 958 / 13 | 1108 / 15 | 5 |
| STM8 |
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| Cosmic | 462 / 8 | 729 / 13 | 974 / 15 | 5 |
| IAR | 664 / 8 | 1053 / 13 | 1388 / 15 | 13 |
| Raisonance | 434 / 8 | 709 / 13 | 918 / 15 | 5 |
* - see Note 4 below
Test modes:
- min (minimal services set)
- priorities are OFF
- allowed: binary semaphores, flags, messages
- 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
- 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:
- 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;
- all test were compiled with maximum optimization;
- in addition OSA requares RAM for task deskriptors;
- 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;
- memory usage can be reduced by disabling priority and by using one byte timers (see OSAcfg.h).
