# Dual Core usage from BufferCreateStaticWithCallback

**URL:** <https://forums.freertos.org/t/dual-core-usage-from-buffercreatestaticwithcallback/16320>\
**Category:** Kernel\
**Created:** [December 5, 2022, 9:35am UTC](https://forums.freertos.org/t/dual-core-usage-from-buffercreatestaticwithcallback/16320 "2022-12-05T09:35:21Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![dookei](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/dookei/32/2927_2.png) [@dookei](https://forums.freertos.org/u/dookei)\
**Post date:** [December 5, 2022, 9:35am UTC](https://forums.freertos.org/t/dual-core-usage-from-buffercreatestaticwithcallback/16320/1 "2022-12-05T09:35:21Z")

</div>

Hi there,  
this is follow up question from the [STM32H Dual Core AMP Demo - #12 by dookei](https://forums.freertos.org/t/stm32h-dual-core-amp-demo/16159/12) .(topic was already closed)  
It relateds to the usage from the xMessageBufferCreateStaticWithCallback in dual core systems.

I used this as guide :[FreeRTOS xMessageBufferCreateStatic() API documentation](https://freertos.org/xMessageBufferCreateStatic.html)

For the AMP implementation when using **xMessageBufferCreateStaticWithCallback**  
I can only define and implement the callbacks for the core that is transmitting the message. Right?

So on the core that is transmitting the message I have

```auto
xMessageBufferWithCallback = xMessageBufferCreateStaticWithCallback( 
                                     sizeof( ucMessageBufferWithCallbackStorage ),
                                     ucMessageBufferWithCallbackStorage,
                                     &xMessageBufferWithCallbackStruct,
                                     vSendCompletedCallback,
                                     vReceiveCompletedCallback );

```

and then the call for the vSendCompletedCallback that is going to generate the interrupt on the partner core.

```auto
void vSendCompletedCallback( MessageBufferHandle_t xUpdatedBuffer, BaseType_t xIsInsideISR, BaseType_t * const pxHigherPriorityTaskWoken )
{
	/* Writes the handle of the data message buffer to which data was written to the control message buffer*/
	while( xMessageBufferSend( xControlMsgBuff_Tx, &xUpdatedBuffer, sizeof( xUpdatedBuffer ), mbaDONT_BLOCK ) != sizeof( xUpdatedBuffer ) )
	{
		/* Nothing to do here. */
	}
	GENERATE_EXTI(EXTI_LINE_TX_DISP_SEND_COMP); /* Generate interrupt on the other core */
}

void vReceiveCompletedCallback( MessageBufferHandle_t xMessageBuffer, BaseType_t xIsInsideISR, BaseType_t * const pxHigherPriorityTaskWoken )
{
 // do nothing this will be implemented by the ISR 
}

/* Interrupt generated by the partner core when the message was read from the buffer */
void IPC_COM_ISR_Tx( void )
{
	BaseType_t xHigherPriorityTaskWoken = pdFALSE;
	//TODO configASSERT( xM7AMPTask );
	CLEARFLAG_EXTI(EXTI_LINE_TX_DISP_REC_COMP);
	xMessageBufferReceiveCompletedFromISR( xDataMsgBuff_Tx, &xHigherPriorityTaskWoken ); 
	/* Normal FreeRTOS "yield from interrupt" semantics, where
	xHigherPriorityTaskWoken is initialized to pdFALSE and will then get set to
	pdTRUE if the interrupt unblocks a task that has a priority above that of
	the currently executing task. */
	portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
}

```

That means that the core that is receiving the message (and not creating the message buffer) wont have a call back since we didnt created the message buffer. Or am I missing something here ( I must 🙄)

On the receiving core I have ISR that is going to notify that a message was sent to the buffer and is available to be received.

void IPC\_COM\_ISR\_Rx(void) // interrupt generated from the partner Core to indicate a message wa sent to the buffer.

```auto
void IPC_COM_ISR_Rx(void) // interrupt generated from the partner Core to indicate a message wa sent to the buffer 
{
	MessageBufferHandle_t xUpdatedMessageBuffer;
	BaseType_t xHigherPriorityTaskWoken = pdFALSE;

		/* xControlMessageBuffer contains the handle of the message buffer that contains data. */
		if( xMessageBufferReceiveFromISR( xControlMsgBuff_Rx, &xUpdatedMessageBuffer, sizeof( xUpdatedMessageBuffer ), &xHigherPriorityTaskWoken )
				== sizeof( xUpdatedMessageBuffer ) ){
				/* Call the API function that sends a notification to any task that is
	    	blocked on the xUpdatedMessageBuffer message buffer waiting for data to
	    	arrive. */
			xMessageBufferSendCompletedFromISR( xUpdatedMessageBuffer, &xHigherPriorityTaskWoken );
		}
	/* Did sending to the queue unblock a higher priority task? */
	if( xHigherPriorityTaskWoken ){
		portYIELD_FROM_ISR( xHigherPriorityTaskWoken );
	}
}

```

After that the blocked task will read the message buffer and (I assume) execute the default implementation from **sbRECEIVE\_COMPLETED( pxStreamBuffer )**. Or am I missunderstanding something ?

```auto
		xReceivedBytes = xMessageBufferReceive(
									xDataMsgBuff_Rx, /* Handle of message buffer. */
									&xReceivedMsg, /* Buffer into which received data is placed. */
								    sizeof( Message_IPC ),	/* Size of the receive buffer. */
									IPC_COM_WAIT_RX ); /* Time to wait for data to arrive. */
		

```

I would appreciate if anyone could shed some light in this topic.

Cheers

---

<div class="post-metadata">

**Author:** ![aggarg](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/aggarg/32/4245_2.png) [@aggarg](https://forums.freertos.org/u/aggarg)\
**Post date:** [December 8, 2022, 8:05am UTC](https://forums.freertos.org/t/dual-core-usage-from-buffercreatestaticwithcallback/16320/2 "2022-12-08T08:05:55Z")

</div>

Did you try [this suggestion](https://forums.freertos.org/t/stm32h-dual-core-amp-demo/16159/15)?

PS - Since you have opened this new issue, lets continue the discussion here.

---

<div class="post-metadata">

**Author:** ![dookei](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/dookei/32/2927_2.png) [@dookei](https://forums.freertos.org/u/dookei)\
**Post date:** [December 8, 2022, 11:05am UTC](https://forums.freertos.org/t/dual-core-usage-from-buffercreatestaticwithcallback/16320/3 "2022-12-08T11:05:41Z")

</div>

Hi @aggarg not yet I will most defenitely test it… I might have a solution for the problem in case it does not work.  
PS: I might need some time to reply …hollidays are coming in and I might be 2/3 weeks offline. Please leave the topic open for that time. Thanks

---

<div class="post-metadata">

**Author:** ![kstribrn](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/kstribrn/32/2085_2.png) [@kstribrn](https://forums.freertos.org/u/kstribrn)\
**Post date:** [December 8, 2022, 5:26pm UTC](https://forums.freertos.org/t/dual-core-usage-from-buffercreatestaticwithcallback/16320/4 "2022-12-08T17:26:06Z")

</div>

@dookei We can definitely leave this open for you. If it does get closed (by accident), don’t hesitate to reopen this with a comment.

---

<div class="post-metadata">

**Author:** ![dookei](https://d3iykfbgfh8zhg.cloudfront.net/user_avatar/forums.freertos.org/dookei/32/2927_2.png) [@dookei](https://forums.freertos.org/u/dookei)\
**Post date:** [January 16, 2023, 4:20pm UTC](https://forums.freertos.org/t/dual-core-usage-from-buffercreatestaticwithcallback/16320/5 "2023-01-16T16:20:56Z")

</div>

Hi @aggarg ,  
YES the solution you provided works. Would it be possible to integrate this in future FreeRTOS releases?  
This way would support multi core systems.  
Many thanks !