Questions tagged [rtos]

A Real Time Operating System - one used typically in industrial control systems. characterized by a predicable response time to interrupts and system requests. Designed in such a way that the developer can be sure of meeting timing requirements of industrial processes.

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35 views

Tasks inside Interrupt Handler

Is there any schedular that exists for STM32F103 in which the 'tasks' are run at the ISR() level while the Schedular() code runs in the main() thread?
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1answer
55 views

Implementation of RTOS in irrigation embedded application on stm32

I have designed a small project in which i have two sensor nodes(stm32) with each sensing temp, humidity and soil moisture and actuating the relay based on some threshold of moisture value. These ...
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122 views

Is mbed OS suitable for hard real time systems [closed]

I have been developing embedded stm applications bare metal along with ST Hal for a few years and would still consider my self a beginner as the process of learning in a bare metal environment can be ...
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1answer
51 views

STM32 - SPI - RTOS problem [closed]

I'm working on a project that uses a 2.8" arduino LCD. The LCD uses an ILI9341 driver. Now I'm testing this library: https://github.com/martnak/STM32-ILI9341 with an STM32F4-Discovery board (STM32F407)...
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1answer
53 views

Timer Interrupt Setup in ThreadX

We're trying to set up ThreadX for the first time and we're trying to understand all the timer settings that. Although there are basically two constants that we need to set, they are not really clear ...
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441 views

Using stop mode in freeRTOS on a STM32L0 and waking up using EXTI interrupt

I want to make a low power device, running freeRTOS. There are 3 threads, which I planned to suspend normally into stop mode and resume execution depending on an EXTI interrupts. I intended doing so ...
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1answer
114 views

What is a RTOS, is it embedded or do I need to install? (MSP430) [closed]

First of all, I have the basic knowledge in low-level programming of microprocessors but I don't have the in-depth details which I need. I have never worked with RTOS before in my previous class. Now ...
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2answers
88 views

Commercial Availability of Bare Metal Automation Controllers [closed]

When I think of commercial automation controllers, I typically see 2 levels of system complexity. First, at a lower level, PLC's programmable with ladder logic, structured text or another 61131-3 ...
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2k views

UART interrupt handling using FreeRTOS

I have two threads: 1. ReadFromUART(): It reads from UART (RX), parses the message and put a command on the messageQueue 2. CommandHandler(): If a message is present in the messageQueue, It execute ...
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1answer
249 views

C++ RTOS Options [closed]

What are some off the open source, popular choices for a C++ compatible RTOS (besides mbed)? I've heard that FreeRTOS doesn't provide official support for C++ compilation and it's a nightmare getting ...
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2answers
257 views

FreeRTOS - Potential issues with Periodic Tasks

Suppose Task 1 has the highest priority of all tasks, and is run periodically using vTaskDelayUntil(). Task 2 has a lower priority, but is also required to run periodically in strict time intervals. ...
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1answer
169 views

How do Free-RTOS and mbed OS handle ethernet?

Do Free-RTOS and mbed OS poll for incoming data to be received (or use interrupts?)? If so, is there a risk that data to be received while the processor is handling another task (e.g. running a ...
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2answers
255 views

RTOS Over UART protocol

I am developing an UART protocol to ensure communication between two boards (Master board and Slave board). Slave board includes many sensors and actuators and Master board shall command this board by ...
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2answers
1k views

Control an UART protocol with FreeRTOS or Interrupts [closed]

I am trying to develop an UART protocol to allow communication between two boards Master_Board and Slave_Board. Master_Board shall send commands over UART to Slave_Board and the latter shall answer. ...
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3answers
293 views

What are the details about link files and startup code one needs to know to write an Operating System for a uC? [closed]

I know some people will say I don't need to write an OS because there are lots of options out there. But I'm not interested in using an OS to solve an specific problem. I want to write one by myself ...
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62 views

Getting error while opeing “.cfg” file with the XGCONF tool

I got some strange errors in ccs. I'm using a cc2640r2f IC and downloaded there simple_periphal_oad_on_chip from resource explorer. Whenever I open the .cfg file with the XGCONF tool I get an error ...
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2answers
1k views

Do microcontrollers support threading?

It has been a while since I took "Embedded Systems" course where we studied "Super-Loops", "RTOS", Semaphores, Multitasking (cooperative vs premptive) so sorry for this question. We have an an ...
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1answer
332 views

Basic RTOS concept. Tasks communication

I am learning to use a RTOS, CMSIS RTOS in this case, so my question is basic. I want to know what is the best way to share information between two tasks. What I am trying to do is basically a ...
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2answers
646 views

Best choice in ARM Cortex series for running RTOS A-,R- or M? [closed]

I am learning about ARM Cortex based systems. I understand that most of the Cortex series can support running an OS. When it comes to real time operating systems implementation on an embedded system, ...
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1answer
494 views

Reasons to use RTOS [duplicate]

Can someone explain in what situations is RTOS used? What are pros and cons of RTOS relative to simple MCU applications with no OS?
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0answers
75 views

Handling RFID time response functions in C

I'm developing an embedded app, writen in C, using a M16C/28 uC from Renesas. The app manages two simple task: RFID for detection and reading MIFARE tags. ( Using HW: Mf500 from NXP ). The uC ...
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1answer
232 views

RTOS and OS working side by side in cooperative work

I would like to use use a RTOS and OS side by side to implement a cooperative work. The RTOS would perform time critical (real-time) task and the OS will perform the other non-critical ...
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1answer
123 views

What are the rules that function should pass in order to be used in RTOS

I use ATSAM4LC2A ARM microcontroller that drives 3xUSART, GPIOs, DMA. timers with the use of interrupts and all the remaining logic of my application.. The project is functional but with out a RTOS ...
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1answer
95 views

ARM compatibility between vendors, with and without RTOS (FreeRTOS) [duplicate]

I would like to know how much compatibility can I expect between ARM MCUs from different vendors. For example, let's say I write a firmware using C language for a Cortex M0 using its CAN peripheral. ...
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2answers
181 views

VxWorks on TI Launchpad Boards

I am trying to find out if VxWorks will be able to run on something similar to the TI EK-TM4C123GXL board (http://www.ti.com/ww/en/launchpad/launchpads-connected-ek-tm4c123gxl.html). It looks like ...
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2answers
212 views

Micrium Rtos - OSTimeDly not working

I have initialized the Micrium Rtos and there is no error when I compile the project but there is a OSTimeDly function in my code that is not working. I should notify that when I give the first ...
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2answers
82 views

Device Driver function behavior on interrupt

Suppose an embedded system is running FreeRTOS and an application program makes calls to a device driver interface (let us assume I2C). What exactly happens when this is interrupted by an external ...
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1answer
4k views

How does the TCP/IP stack interact with Wifi components?

I'm trying to transition beyond Arduino and I'm trying to learn how to use an RTOS (like FreeRTOS) to connect to the web via Wifi. It seems that FreeRTOS and ZentriOS and other RTOS supply TCP/IP ...
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1answer
619 views

Hardfault exception on stm32f7 arm microprocessor at RTX thread creation

I'm running a simple RTX thread program as follows. The problem is when it's running on STM32F7 DISCOVERY BOARDv through debug interface, it seems right after running the ...
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1answer
9k views

Minimum Requirements of a microcontroller to run embedded Linux? [closed]

I am looking for the cheapest microcontroller to run embedded Linux. what should I be looking at, which class of microcontrollers or microprocessors is compatible? is there a minimum system ...
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0answers
114 views

When should one use a RTOS (real-time OS) over a simple infinite while loop in an embedded system? [duplicate]

The Arduino uses a simple infinite while loop. It works fine for me so far. What are some situations when a more complex RTOS is needed?
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1answer
284 views

Why event flag related functions does not work correctly outside of tasks in keil rtx?

As you know event flags are very useful (e.g. let task running),but unfortunately their control functions (os_evt_clr/set/wait) does not work outside of tasks bodies correctly(e.g. in interrupt ...
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4answers
821 views

Real time operating systems

I have been asked this question: “Do you think the system will need deterministic time or real time responses?” The problem I have is distinguishing the difference between the two. I know that a real ...
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4answers
580 views

How to handle polling method in micro controllers.?

I am using PIC32MX795F512L Micro Controller. I need to develop an application where 4 led's connected to pins of controller will blink continuously at a rate of 1sec and there are 15 inputs ...
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5answers
2k views

How come RTOSs are considered deterministic?

On a pc (an OS of course) any C program becomes indeterministic in terms of timing. For instance a loop takes between 1.2 and 1.3 seconds depending on "how fast I am moving another window". It is ...
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1answer
900 views

RTOS: Micrium uCOS vs Mentor Graphics Nucleus

We're working on a wearable IoT device, and I'm hoping for some guidance on the common commercially available RTOS, such as what's the difference between the two. As of current I'm leaning toward ...
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1answer
2k views

differences between privileged mode and unprivileged mode in the RTX RTOS

As i said in the title what's differences between privileged mode and unprivileged mode in the RTX RTOS? And why in privileged mode threads has allowed full access to the cortex M processor?
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2answers
418 views

Free RTOS For PIC24fJ128GA202? [closed]

I was working on PIC24fJ128GA202 microcontroller for 2 months, Since my application getting more complicated i decided to program on multitasking in pic microcontroller it is much complicated to do ...
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6answers
5k views

Multitasking on PIC microcontrollers

Multitasking is important these days. I wonder how we can achieve it in microcontrollers and embedded programming. I am designing a system which is based on a PIC microcontroller. I have designed its ...
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1answer
1k views

What is the difference between CMSIS RTOS and Keil RTX?

I have read the articles about them separately, but there are no information about the relation between them. What I understood is that there is CMSIS RTOS that ARM created and Keil extended it to ...
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1answer
123 views

Scheduling the transmision of CAN frames in an RTOS

I'm planning to use my STM32 board to send CAN frames. I implemented a simple scheduler that contains 10 tasks; one task will be responsible for sending frames. To do the job I declared a structure ...
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1answer
2k views

External RAM with ARM Cortex M-3

I'm planning to start with uclinux with my ARM cortex M-3 based MCU . Uclinux's requirements include ~4MB of RAM (SRAM - DRAM - .. whatever) and flash (SD card - NAND Flash - ... whatever). My MCU ...
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1answer
2k views

How to flush an RTOS queue and prevent further posting on a device disconnect event?

In the following code SendMessage() is the API called by the user to send a message over USB Task() is the thread created in <...
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1answer
202 views

Events in FreeRTOS 7.1.1

I'm looking for method how to inform one task in firmware about change somewhere else (Using FreeRTOS 7.1.1). I need to receive information about changes, but I wouldn't want check value in cycle - ...
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0answers
579 views

SD Card Buffer in FreeRTOS [closed]

One of my tasks in a project is responsible for gathering information about values measured from sensors and write information in a .txt file on an SD card. What would be the best way to do this? ...
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3answers
7k views

Queues in FreeRTOS

I have multiple tasks that all write to a screen. Obviously without controlling who can write to the screen when I'll have problems. I thought the easiest way to do this was with queueing. I have a ...
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1answer
65 views

Calculating processor utilisation

I'm using a Cortex M3 processor on an LPC1769 board. For this particular situation, all processes occur within interrupts. Therefore, within the main "loop" there isn't actually anything to be ...
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1answer
415 views

Measuring time using an STM32F407VGT6 microcontroller

I'm using a custom board for charging and testing batteries. Its 'brain' is an STM32F407VGT6 microcontroller. I'm developing in Ubuntu (14.04.2 LTS), using ChibiStudio (ChibiOS/RT 3.0 development ...
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3answers
2k views

interrupt using Timer0 on PIC18f

Im looking for a little help and advice on my code. Im using C18 in the MPLab environment, PIC18f4520 with Fosc @ 4MHz, and usnig timer0 in 16 bit mode to count to overflow, set the overflow bit and ...
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2answers
498 views

Does priority inheritance cure priority inversion?

In the Mutex description page of the FreeRTOS website the following sentence can be find: Priority inheritance does not cure priority inversion From what I know I thought that priority inheritance ...