Tx_FreeRTOS_Wrapper Application Description
This application provides an example of Azure RTOS ThreadX stack
usage, it shows how to develop an application using the FreeRTOS
adaptation layer for ThreadX.
The main entry function tx_application_define() is called by ThreadX
during kernel start, at this stage, the application creates 1 thread :
‘LED_Thread’ (Priority : 5).
The ‘LED_Thread’ toggles the ‘LED_GREEN’ every 500ms.
Expected success behavior
‘LED_GREEN’ toggles every 500ms.
Error behaviors
‘LED_GREEN’ is turrned off and the program enters an infinite
loop.
Assumptions if any
None
Known limitations
None
Notes
To optimize the application footprint, the following ThreadX
configuration options should be enabled in the tx_user.h file:
#define TX_DISABLE_PREEMPTION_THRESHOLD
#define TX_DISABLE_NOTIFY_CALLBACKS
#define TX_DISABLE_REDUNDANT_CLEARING
#define TX_DISABLE_STACK_FILLING
#define TX_NOT_INTERRUPTABLE
#define TX_TIMER_PROCESS_IN_ISR
#define TX_DISABLE_ERROR_CHECKING
ThreadX usage hints
- ThreadX uses the Systick as time base, thus it is mandatory that the
HAL uses a separate time base through the TIM IPs.
- ThreadX is configured with 100 ticks/sec by default, this should be
taken into account when using delays or timeouts at application. It is
always possible to reconfigure it in the “tx_user.h”, the
“TX_TIMER_TICKS_PER_SECOND” define,but this should be reflected in
“tx_initialize_low_level.s” file too.
- ThreadX is disabling all interrupts during kernel start-up to avoid
any unexpected behavior, therefore all system related calls (HAL, BSP)
should be done either at the beginning of the application or inside the
thread entry functions.
- ThreadX offers the “tx_application_define()” function, that is
automatically called by the tx_kernel_enter() API. It is highly
recommended to use it to create all applications ThreadX related
resources (threads, semaphores, memory pools…) but it should not in any
way contain a system API call (HAL or BSP).
- Using dynamic memory allocation requires to apply some changes to
the linker file. ThreadX needs to pass a pointer to the first free
memory location in RAM to the tx_application_define() function, using
the “first_unused_memory” argument. This require changes in the linker
files to expose this memory location.
- For EWARM add the following section into the .icf file:
place in RAM_region { last section FREE_MEM };
either define the RW_IRAM1 region in the ".sct" file
or modify the line below in "tx_initialize_low_level.S to match the memory region being used
LDR r1, =|Image$$RW_IRAM1$$ZI$$Limit|
- For STM32CubeIDE add the following section into the .ld file:
._threadx_heap :
{
. = ALIGN(8);
__RAM_segment_used_end__ = .;
. = . + 64K;
. = ALIGN(8);
} >RAM_D1 AT> RAM_D1
The simplest way to provide memory for ThreadX is to define a new section, see ._threadx_heap above.
In the example above the ThreadX heap size is set to 64KBytes.
The ._threadx_heap must be located between the .bss and the ._user_heap_stack sections in the linker script.
Caution: Make sure that ThreadX does not need more than the provided heap memory (64KBytes in this example).
Read more in STM32CubeIDE User Guide, chapter: "Linker script".
- The “tx_initialize_low_level.s” should be also modified to enable
the “USE_DYNAMIC_MEMORY_ALLOCATION” flag.
Keywords
RTOS, ThreadX, Threading, RTOS compatibility layers
Hardware and Software
environment
- This application runs on STM32C011F6Ux devices.
- This application has been tested with STMicroelectronics
STM32C0116-DISCO boards Revision MB1684 A-02 and can be easily tailored
to any other supported device and development board.
How to use it ?
In order to make the program work, you must do the following:
- Open your preferred toolchain
- Rebuild all files and load your image into target memory
- Run the application