Have a question about Micrium's embedded software? Ask our Expert, Matt Gordon

Dear Matt, I have a hardware platform based in the ATMEGA 2560 16AU. I wonder if the micrium uC_OS can be ported for that micro?

Regards

Cristian Barros

Cristian,

Yes, Micrium's engineers have already ported uC/OS-II to the ATmega2560.  You can download an example project that incorporates their port files (along with the full source code of the kernel) from the knode: http://www.element14.com/community/docs/DOC-37677/l/project--μcos-ii-and-μcos-view-for-atmel-avr-atmega2560.

Regards,

Matt

Hi Matt,

Does uC/OS-III support co-operative multitasking i.e. a task can run without interruption until it suspends itself?

Regards,

Peter.

Peter,

uC/OS-III is a preemptive kernel, so the possibility generally exists that one task might interrupt another.  However, application code ultimately decides whether or not preemption takes place.  If an application's ISRs never invoke kernel functions to ready tasks, then those ISRs will not result in preemption.  Likewise, if the kernel's own ISR, the tick interrupt handler, does not ready any tasks (which should happen if application code avoids using the kernel's time-delay and time-out services), then it will not cause tasks to preempt each other.  Cooperative behavior, then, can be brought about with uC/OS-III, but is not typical of applications that incorporate the kernel.  

Regards,

Matt

Hello,
I've found the following product from Micrium: BKX-TCPX-STF107-P-P1, but the description is very short.
I would like to make sure it contains Micrium TCP/IP stack (=software licence) and not only the book about uC/TCP-IP?
If yes - does it also include Micrium add-on to uC/TCP-IP called SNMP?
As per Micrium web page to use TCP/IP I also need Micrium uC/OS. Is it included in this product?

John,

From what I see, having the radio transmitter plug into the compact flash socket and transmit to a remote memory is kind of unique to eye-fi and a few others like Cisco / Linksys.   Wireless CompactFlash Card Adapter   data_sheet

You might have better luck if you can insert a wireless link before the compact flash socket.

Hi Matt, I am a newbie to RTOS and i have started with uCOS III.

          OSSemCreate(&MySem,                                                                                 // Creating Semaphore

                       "SerialPortSemaphore",

                                                            1,

                                                            &err);

I want to make my semaphore to enable the UART, but i dont know how. I have made another function that enables the UART and this function is called from the switch statement just after the OSSemPend(...).

Please help me with this, or just show me an example to create and use a semaphore.

Best Regards.

Typically, the purpose of a semaphore used with a UART is to signal the reception of data.  The semaphore post takes place in the UART's receive ISR, and the pend occurs in the code responsible for processing the data.  This setup is illustrated in the below example.  (I've omitted the semaphore creation code from this example, since it would simply involve the function call named above.)

void  UART_ISR (void)

{

    /* Clear interrupt flag */

    OSSemPost (&AppSemUART, OS_OPT_POST_1, &err);

}

void  UART_Task (void *p_arg)

{

    while (1) {

        OSSemPend(&AppSemUART, OS_CFG_TICK_RATE_HZ, OS_OPT_PEND_BLOCKING, 0, &err);

        /* Read from buffer and process data */

    }

}

Regards,

Matt

Not sure if this will help.  AN-1002 Mutual Exclusion Semaphores