Message queues are quite similar. In CMSIS-RTOS, all queues are registered by name, which can make for a richer debugging experience. Also, CMSIS-RTOS supports static allocation via attributes passed in as function parameters.
Any functions called from inside an ISR will automatically be forced to use the FromISR equivalent functions and finish the ISR with a call to portYIELD_FROM_ISR. This results in any blocking times being effectively set to 0. So, for example, if a queue doesn't have space available, a call to osMessageQueuePut will return immediately from inside an ISR, even if a blocking timeout is specified:
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CMSIS-RTOS name |
FreeRTOS functions called |
Notes |
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osMessageQueueDelete |
vQueueUnregisterQueue, vQueueDelete |
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osMessageQueueGet |
xQueueReceive |
The FromISR variant is automatically called and portYIELD_FROM_ISR is automatically called if inside an ISR. |
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osMessageQueueGetCapacity |
pxQueue->uxLength |
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osMessageQueueGetCount |
uxQueueMessagesWaiting, uxQueueMessagesWaitingFromISR |
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osMessageQueueGetMsgSize |
pxQueue->uxItemSize |
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osMessageQueueGetSpace |
uxQueueSpacesAvailable |
taskENTER_CRITICAL_FROM_ISR is automatically called if this function is executed from within an ISR. |
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osMessageQueueNew |
xQueueCreateStatic, xQueueCreate |
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osMessageQueuePut |
xQueueSendToBack, xQueueSendToBackFromISR |
The msg_prior parameter is ignored in the STM port. |
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osMessageQueueReset |
xQueueReset |
Queues are very similar between CMSIS-RTOS and FreeRTOS, but it is worth noting that CMSIS-RTOS doesn't have an equivalent of xQueueSendToFront, so it will not be possible to place items at the front of a queue using CMSIS-RTOS.