andthinker

                          Priority control system and task scheduling in RTOS Implementing priority control system and task scheduling in RTOS Abstract: Real-time operating systems (RTOSs) are becoming increasingly seeming in all places, so controlling a wide variety of such popular and time critical devices and some effective testing techniques could improve the efficiency of these systems. In this paper we differentiate between normal OS and real-time OS. How real-time OS works comparing with our normal OS. In real-time OS we have different type of task scheduling and priority based controlling system where as in normal OS we don’t have this type of controlling and scheduling. And in RTOs we have special feature as like we can assign specific time for each task. Problem statement: Implement a framework for industrial control systems which help to avoid dead-lock occurrence and help us to assign specific ti...

Real time temperature controller system using Arduino Abstract              The documented application discusses common features of temperature control with Arduino and pid implementation. A temperature controller is a device that controls the temperature of a system or process.             It is basically done by measuring the current temperature (process variable), comparing that value against a desired temperature value (set point) and generating an output to change the system or process such that the current temperature matches to the desired temperature.  Introduction             The main objective is to implement or  Build low cost, compatible, portable and user friendly control  system intended for control temperature using the Arduino prototyping platform. Arduino has become a p...

ISR Usage (interrupt service routine) 1.understand how often the interrupt occurs 2.understand how much time it takes to service each interrupt 3.Make sure there is enough time to service all interrupts and to still get work done in the main loop there's only 1 sec of compute time per second to get everything done! -Keep ISRs short and simple.  (short = short time, not short code length) Do only what has to be done then RETI. Long ISRs may preclude others from being run Ask yourself, “Does this code really need to be here?” -Example:  alarm clock with 1Sec interrupts: -at interrupt, just increment the “seconds counter” and return -in the main code loop we can -do binary to BCD conversion  -lookup display code -write to display Effecting main program flow with ISRs ISRs are never called by the main routine.  Thus, -nothing can be passed to them (there is no “passer”) -they can return nothing (its not a real func...

ISR Interrupt Service Routine ISR Interrupt Service Routine is the software(program) service it will execute  when interrupt will generates.When interrupt signal comes to micro controller controller will stop the its current execution and it will go to the interrupt vector table and it will get the address of ISR Interrupt Service Routine and it will execute ISR Interrupt Service Routine program and it will return back to main program. AVR interrupt servicing  1. In response to the interrupt, the CPU finishes any pending instructions      and then ceases fetching further instructions.  Global Interrupt Enable      (GIE) bit is cleared. 2. Hardware pushes the program counter on the stack.   3. The CPU fetches the instruction from the interrupt vector table that      corresponds to the interrupt. This instruction is usually “jmp, address”.      The address is the address of the ISR. ...

Interrupts Interrupts are the signal to the microcontroller or processor to mark the event that requires immediate attention. An interrupt is “requesting" the processor to stop to perform the current program and to “make time” to execute a special code(interrupt code). Whenever any device needs its interrupt service, the device notifies the microcontroller by sending it an interrupt signal. Upon receiving an interrupt signal, the microcontroller program_counter will go to the Interrupt vector table in that it will fetch the ISR address (interrupt service routine) and it will execute the ISR program and it will return to the main program where it stopped and it will start executing main program . Interrupts An interrupt is an exception, a change of the normal progression, or interruption  in the normal flow of program execution.   An interrupt is essentially a hardware generated function call. Interrupts are caused by both internal and external...

Interrupts vs. Polling Polling:  In the Polling method, the microcontroller must "access by himself" the device and “ask” for the information it needs for processing. In fact, we see that in the Polling method the external devices are not independent systems; they depend on the microcontroller, and only the micro is entitled to obtain access to the information it needs Interrupts: Interrupts are the signal to the microcontroller or processor to mark the event that requires immediate attention. An interrupt is “requesting" the processor to stop to perform the current program and to “make time” to execute a special code(interrupt code). Whenever any device needs its interrupt service, the device notifies the microcontroller by sending it an interrupt signal. Upon receiving an interrupt signal, the microcontroller program_counter will go to the Interrupt vector table in that it will fetch the ISR address (interrupt service routine) and it will execute the ISR...

RTOS Real time operating system interview questions  RTOS 1. What is a Real-Time System? Ans:Real time system means is system which is having time critical application . System should accept and complete the task without buffer . RTOS Definition 1: A real-time system is one that must process information and produce a response within a specified time, else risk severe consequences, including failure. That is, in a system with a real-time constraint it is no good to have the correct action or the correct answer after a certain deadline: it is either by the deadline or it is useless! Definition 2 (modified from The Oxford Dictionary of Computing): Any system in which the time at which output is produced is significant. This is usually because the input corresponds to some event in the physical world, and the output has to relate to that same event. The lag from input time to output time must be sufficiently small for acceptable timeliness Definition 3 (Yo...