Nt1310 Unit 10 Research Paper

Paper II - Section : II Embedded Systems INDEX No 1 2 3 4 5 6 7 8 9 10 Toggle Port LED Simulate Binary Counter at Port Generate delay using TIMER_0 Stepper Motor (clockwise/Anticlockwise) Generating square wave at port pin Generating Triangular wave at port pin Sine wave generation using look-up table Microcontrollers communicating over a serial link Read switch-status from i/p port and display at o/p port Using Input Capture Pin (ICP), measure pulse width & display at o/p port Topic Date 6-9-2010 9-9-2010 17-9-2010 24-9-2010 8-10-2010 15-10-2010 15-10-2010 29-10-2010 22-11-2010 24-11-2010 Page 02 03 04 06 07 09 10 11 13 15 Sign

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Practical – 01 Toggle Port LED Aim : Write a program in embedded C programming language to alternately ON/OFF
Components Used: i)AT90S8535 Micro controller ii)LED‟S iii)Ground Code: #include int timeCount = 0; interrupt[TIM0_OVF] void timer0_ovf_isr(void) { TCNT0 = 6; if(++timeCount == 1000) { PORTA =PORTA ^ 0x01; timeCount = 0; } } void main(void) { DDRA = 0x01; PORTA = 0x01; TCCR0 = 0x02; TIMSK = 0x01; #asm("sei"); while(1); } Description: A variable timecount is initialized to 0. In the main function the LSB of PORTA is chosen for output and it is set to 1. Then the TIMER COUNTER CONTROL REGISTER (TCCR0) is initialized in such a way that divide by 8 (CK/8)clock source is selected again the “timer interrupt mask is set to enable the timer0 counter. “#asm” is a assembly language instruction „sei‟ stands for set enable interrupts to enable all the interrupts. Finaly ainfinite while loop.Then the function with keword interrupt is created.This function will be called automatically when the timer0 overflow interrupt takes place. This function returns nothing, since it is not called by any function and you cant pass any thing to function for the same reason .The timer0 is initialized to 6 in this function .As we have chosen ck/8 system as mentioned above and the clock frequency is 4 Mhz that‟s why 4/8 Mhz so 500 Khz(0.5 Mhz) will be the effective frequency so for one tick of counter 1/0.5 micro sec are required(1/freq.= time) that equals to 2 micro secondes. A timer can