Before we start to work with a micro controller it is mandatory to understand what the available features of the micro controller are. Whenever we go for the development of a project we used to think on the very practical aspects such as:
The product to be in a low cost.
Size of the system to be small.
Efficiency of the system to be high.
Power consumption to be very low
Lets have a look of the available features of the AT89S52 micro controller in which we are going to work out
8 Kilo Bytes of In-System programmable Flash Memory.
Operating voltage level between 4Volts and 5.5Volts.
4 General Purpose Input Output ports (8 Bits)
32 Numbers of Programmable IO lines
Full duplex UART serial channel.
Eight Sources of Interrupts.
Three numbers of Timer/Counter.
When we start to write our Embedded C codes for this controller we should not forget that we are Bounded to memory which is 8KB of the total ISP flash memory which is available within the controller. Since this controller is having internal Timers/Counters there is no requirement for the external timing or counting device. Our controller also supports communication protocols like UART, SPI. We can perform the full duplex communication system in Universal Asynchronous Receiver Transmitter protocol. The AT89S52 micro controller is available with the special function registers.
Interrupt Registers available with the controller is one of the very important feature of the controller which grabs the attention of the controller and also helps in saving the time wasted in waiting for the occurrence of a required case condition. Various available interrupts of 8051 will be discussed on the further posts.
Three Timers available with 8051 has various features. Those various features like timer with prescaling bits, 16 bit timers, 8 bit timers with auto reload, split timers can be made available by setting the modes of operation of the Timer registers available. For more features of the controller manufacturer’s page.
Other than the available features of the controller by the manufacturer we can implement the single controller to numerous of applications by connecting the appropriate peripheral device.
A peripheral device can be any device which can assist the controller in completing the operation. For example the timers of 8051 can make use of the internal gate signals for its operation. The gate pulse can also be provided externally by setting the values of the special function registers with the help of any pulse producing circuitry. The very commonly known Integrated circuit 555 can be used.
Various interfacing devices can be connected to the micro controller according to the application we are building for such as , led, lcd, seven segmentdisplays, temperature, pressure, moisture, lpg detection, IR, TSOP sensors, servo, stepper, bldc motors,etc.,.
For example let us consider one of the application which we encounter in our day to day life, A petrol bunk station. Here we can build it with 8051 controllers along with the interfacing devices like the displays to show the values to the customers and the operator, interfacing switches for entering the values of the quantity or the price which the customer wants to refill, motors for pumping, smart card system(for security and fully automated stations) etc.,.
If you want to become a good Embedded engineer you can read this article Career in Embedded Systems
In the further sessions lets discuss about the interfacing of the various input and output devices with our 8051 controller.