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freertos_twi_master NULL pointer in queue

Posted by godi22 on February 23, 2019

Hello, I work with a Atmel/Microchip SAM4E µC and use TWI (I²C). Operating system is freeRTOS V10.0.1 Compiler: GNU Arm Embedded Toolchain 7-2018-q2

I replaced the twimaster (from ASF V3.44) init, read and write functions with the equivalent functions (without async) from the freertostwi_master file.

Now I have the problem, that the queue.c calls in the function xQueueGenericSend (line 731) the configASSERT makro, because QueueHandle_t xQueue is a NULL-Pointer.

If I add into the xQueueGenericSend function a return when the xQueue is NULL, it seems to be all correct. Because, I receive the same data with the Atmel twi_master software.

Unfortunately, I can not quite understand where the NULL pointer comes from, or why this occurs at all. It must have something to do with the semaphores.

Has anyone already had the same problem and solved, or an idea why it comes to the NULL pointer?

freertos_twi_master NULL pointer in queue

Posted by rtel on February 23, 2019

Those drivers are rather old and I don’t have them myself so can’t look directly. However I think because of changes in the way priority inherent works they are probably not compatible with FreeRTOS v10 (although that should not be the source of the null pointer).

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