Convention Changes

There are a number of convention changes from µC/OS-II to µC/OS-III. The most notable is the use of CPU-specific data types. The table below shows the differences between the data types used in both kernels.

µC/OS-II vs. µC/OS-III basic Data Types

µC/OS-II (`os_cpu.h`)	µC/CPU (`cpu.h`)	Note
`BOOLEAN`	`CPU_BOOLEAN`
`INT8S`	`CPU_INT08S`
`INT8U`	`CPU_INT08U`
`INT16S`	`CPU_INT16S`
`INT16U`	`CPU_INT16U`
`INT32S`	`CPU_INT32S`
`INT32U`	`CPU_INT32U`
`OS_STK`	`CPU_STK`	(1)
`OS_CPU_SR` µC/OS-II (`os_cfg.h`)	`CPU_SR` µC/CPU (`cpu.h`)	(2)
`OS_STK_GROWTH`	`CPU_CFG_STK_GROWTH`	(3)

(1) A task stack in µC/OS-II is declared as an OS_STK , which is now replaced by a CPU specific data type CPU_STK . These two data types are equivalent, except that defining the width of the CPU stack in µC/CPU makes more sense.

(2) It also makes sense to declare the CPU’s status register in µC/CPU.

(3) Stack growth (high-to-low or low-to-high memory) is declared in µC/CPU since stack growth is a CPU feature and not an OS one.

Another convention change is the use of the acronym “ CFG ” which stands for configuration. Now, all #define configuration constants and variables have the “ CFG ” or “ Cfg ” acronym in them as shown in the table below. This table shows the configuration constants that have been moved from os_cfg.h to os_cfg_app.h . This is done because µC/OS-III is configurable at the application level instead of just at compile time as with µC/OS-II.

µC/OS-III uses "CFG" in configuration

µC/OS-II (os_cfg.h)	µC/OS-III (os_cfg_app.h)	Note
	`OS_CFG_MSG_POOL_SIZE`
	`OS_CFG_ISR_STK_SIZE`
	`OS_CFG_TASK_STK_LIMIT_PCT_EMPTY`
`OS_TASK_IDLE_STK_SIZE`	`OS_CFG_IDLE_TASK_STK_SIZE`

	`OS_CFG_STAT_TASK_PRIO`
	`OS_CFG_STAT_TASK_RATE_HZ`
`OS_TASK_STAT_STK_SIZE`	`OS_CFG_STAT_TASK_STK_SIZE`
`OS_TICKS_PER_SEC`	`OS_CFG_TICK_RATE_HZ`	(1)
	`OS_CFG_TICK_TASK_PRIO`
	`OS_CFG_TICK_TASK_STK_SIZE`
	`OS_CFG_TMR_TASK_PRIO`
`OS_TMR_CFG_TICKS_PER_SEC`	`OS_CFG_TMR_TASK_RATE_HZ`
`OS_TASK_TMR_STK_SIZE`	`OS_CFG_TMR_TASK_STK_SIZE`

(1) The very useful OS_TICKS_PER_SEC in µC/OS-II was renamed to OS_CFG_TICK_RATE_HZ in µC/OS-III. The “ HZ ” indicates that this #define represents Hertz (i.e., ticks per second).

The table belowshows additional configuration constants added to os_cfg.h , while several µC/OS-II constants were either removed or renamed.

µC/OS-III uses "CFG" in configuration

µC/OS-II (os_cfg.h)	µC/OS-III (os_cfg.h)	Note
`OS_APP_HOOKS_EN`	`OS_CFG_APP_HOOKS_EN`
`OS_ARG_CHK_EN`	`OS_CFG_ARG_CHK_EN`
	`OS_CFG_CALLED_FROM_ISR_CHK_EN`
`OS_DEBUG_EN`	`OS_CFG_DBG_EN`	(1)
`OS_EVENT_MULTI_EN`
`OS_EVENT_NAME_EN`		(2)

`OS_MAX_EVENTS`		(3)
`OS_MAX_FLAGS`		(3)
`OS_MAX_MEM_PART`		(3)
`OS_MAX_QS`		(3)
`OS_MAX_TASKS`		(3)
	`OS_CFG_OBJ_TYPE_CHK_EN`
`OS_LOWEST_PRIO`	`OS_CFG_PRIO_MAX`
	`OS_CFG_SCHED_LOCK_TIME_MEAS_EN`
	`OS_CFG_SCHED_ROUND_ROBIN_EN`
	`OS_CFG_STK_SIZE_MIN`
`OS_FLAG_EN`	`OS_CFG_FLAG_EN`
`OS_FLAG_ACCEPT_EN`		(6)
`OS_FLAG_DEL_EN`	`OS_CFG_FLAG_DEL_EN`
`OS_FLAG_WAIT_CLR_EN`	`OS_CFG_FLAG_MODE_CLR_EN`
`OS_FLAG_NAME_EN`		(2)
`OS_FLAG_NBITS`		(4)
`OS_FLAG_QUERY_EN`		(5)
	`OS_CFG_PEND_ABORT_EN`
`OS_MBOX_EN`
`OS_MBOX_ACCEPT_EN`		(6)
`OS_MBOX_DEL_EN`
`OS_MBOX_PEND_ABORT_EN`
`OS_MBOX_POST_EN`
`OS_MBOX_POST_OPT_EN`
`OS_MBOX_QUERY_EN`		(5)
`OS_MEM_EN`	`OS_CFG_MEM_EN`
`OS_MEM_NAME_EN`		(2)
`OS_MEM_QUERY_EN`		(5)
`OS_MUTEX_EN`	`OS_CFG_MUTEX_EN`
`OS_MUTEX_ACCEPT_EN`		(6)
`OS_MUTEX_DEL_EN`	`OS_CFG_MUTEX_DEL_EN`
	`OS_CFG_MUTEX_PEND_ABORT_EN`
`OS_MUTEX_QUERY_EN`		(5)
`OS_Q_EN`	`OS_CFG_Q_EN`
`OS_Q_ACCEPT_EN`		(6)
`OS_Q_DEL_EN`	`OS_CFG_Q_DEL_EN`
`OS_Q_FLUSH_EN`	`OS_CFG_Q_FLUSH_EN`
	`OS_CFG_Q_PEND_ABORT_EN`
`OS_Q_POST_EN`		(7)
`OS_Q_POST_FRONT_EN`		(7)
`OS_Q_POST_OPT_EN`		(7)
`OS_Q_QUERY_EN`		(5)
`OS_SCHED_LOCK_EN`
`OS_SEM_EN`	`OS_CFG_SEM_EN`
`OS_SEM_ACCEPT_EN`		(6)
`OS_SEM_DEL_EN`	`OS_CFG_SEM_DEL_EN`
`OS_SEM_PEND_ABORT_EN`	`OS_CFG_SEM_PEND_ABORT_EN`
`OS_SEM_QUERY_EN`		(5)
`OS_SEM_SET_EN`	`OS_CFG_SEM_SET_EN`
`OS_TASK_STAT_EN`	`OS_CFG_STAT_TASK_EN`
`OS_TASK_STK_CHK_EN`	`OS_CFG_STAT_TASK_STK_CHK_EN`
`OS_TASK_CHANGE_PRIO_EN`	`OS_CFG_TASK_CHANGE_PRIO_EN`
`OS_TASK_CREATE_EN`
`OS_TASK_CREATE_EXT_EN`
`OS_TASK_DEL_EN`	`OS_CFG_TASK_DEL_EN`
`OS_TASK_NAME_EN`		(2)
	`OS_CFG_TASK_Q_EN`
	`OS_CFG_TASK_Q_PEND_ABORT_EN`
`OS_TASK_QUERY_EN`		(5)
`OS_TASK_PROFILE_EN`	`OS_CFG_TASK_PROFILE_EN`
	`OS_CFG_TASK_REG_TBL_SIZE`
	`OS_CFG_TASK_SEM_PEND_ABORT_EN`
`OS_TASK_SUSPEND_EN`	`OS_CFG_TASK_SUSPEND_EN`
`OS_TASK_SW_HOOK_EN`
`OS_TICK_STEP_EN`		(8)
`OS_TIME_DLY_HMSM_EN`	`OS_CFG_TIME_DLY_HMSM_EN`
`OS_TIME_DLY_RESUME_EN`	`OS_CFG_TIME_DLY_RESUME_EN`
`OS_TIME_GET_SET_EN`
`OS_TIME_TICK_HOOK_EN`
`OS_TMR_EN`	`OS_CFG_TMR_EN`
`OS_TMR_CFG_NAME_EN`		(2)
`OS_TMR_DEL_EN`	`OS_CFG_TMR_DEL_EN`

(1) DEBUG is replaced with DBG.

(2) In µC/OS-II, all kernel objects can be assigned ASCII names after creation. In µC/OS-III, ASCII names are assigned when the object is created.