Requirements of embedded systems

Requirements of embedded systems:


Reliability.



Most of the embedded systems are not accessible for human intervention, so these systems should work with out resetting or rebooting the system. This calls for very reliable hardware as well as software. If the embedded system comes to halt because of any error, then the system should reset itself without the need of human intervention.

Cost effectiveness:

If the embedded system is designed form consumer application or mass marketing, then the cost of the system should be kept as minimal as possible. This needs the selection of right hardware and software algorithms according the performance requirements.

Eg. CD player, ipod, mobile phones etc.
If the embedded systems are designed for very special purpose applications such as space probe, nuclear plants and for military applications etc, then cost may not be a factor of concern. There, the only criteria is performance.

Low power consumption :

Those embedded systems which are powered by battery should not consume more battery power, as it will drain the batteries. The hardware design engineers should take this account into consideration while selecting hardware. The software algorithm should be such that, the processor should be reverted to low power or sleep or idle mode according to the requirements.

Efficient use of processing power:

The developer should keep in mind the processing power and cost, while selecting a processor. Generally the processing power is specified in terms of Million Instructions Per Second (MIPS). The MIPS requirements should be calculated first and the choose the processor. With the availability of processors from many vendors with similar capabilities, the developer should keep in mind consideration such as the cost for IDE’s, support provided by the vendor and reliability.

Efficient use of memory.

Depending upon the functionality, the developer can calculate the program size and data size based on memory requirements. Most embedded system use RAM and Flash memory as memory elements. Now a days, the cost of memory is going down, but even a byte of memory can make a huge difference in case of designs intended for mass marketing

Approximate execution time :

The software developer needs to ascertain whether the embedded system is a hard real time or soft real time system. Though the software is usually written in assembly languages, but some computation-intensive portions of the code may need to be written in assembly language for desired real time performance.