In this presentation we can learn about basic concept of Timer, types of timer, timer2, features, pre and post scaler - frequency divider clearly.

1. MICROCONTROLLER BASED SYSTEM DESIGN
“TIMER 2 CONCEPT”
V. KALAIRAJAN M.E;
ASSISTANT PROFESSOR,
ELECTRICAL AND ELECTRONICS ENGINEERING,
KONGUNADU COLLEGE OF ENGINERING AND TECHNOLOGY, TRICHY.
1KONGUNADU COLLEGE OF ENGINERING AND TECHNOLOGY, TRICHY TIMER2 CONCEPT

2. “TIMER 2 CONCEPT”
VIEWS:
 TIMER.
 TYPES OF TIMER.
 TIMER2 MODULE.
 PRESCALER - FREQUENCY DIVIDER.
 POSTSCALER - FREQUENCY DIVIDER.
 THE STRUCTURE OF THE OPTION_REG REGISTER.
 BLOCK DIAGRAM OF THE TIMER2 MODULE.
 PIC TIMER2 FORMULA.
KONGUNADU COLLEGE OF ENGINERING AND TECHNOLOGY, TRICHY TIMER2 CONCEPT 2

3. “TIMER 2 CONCEPT”
TIMER:
 Now a days, we plan and build systems that perform various
processes that depend on time.
 Simple example of this process is the digital wristwatch. The role
of this electronic system is to display time in a very precise
manner and change the display every second (for seconds), every
minute (for minutes) and so on.
 To perform the steps we've listed, the system must use a timer,
which needs to be very accurate in order to take necessary actions.
The clock is actually a core of any electronic system.
 Each module can generate an interrupt to indicate that an event has
occurred (i.e. timer overflow). The timer modules are:
 Timer0 Module
 Timer1 Module
 Timer2 Module
3KONGUNADU COLLEGE OF ENGINERING AND TECHNOLOGY, TRICHY TIMER2 CONCEPT

4. “TIMER 2 CONCEPT”
TIMER 2 MODULE:
The Timer2 module, timer/counter, has the following features:
 Two 8-bit registers (TMR2 and PR2).
 Readable and writable.
 A prescaler and a postscaler.
 Connected only to an internal clock - 4 MHz crystal.
 Interrupt on overflow.
PRESCALER - FREQUENCY DIVIDER:
 The prescaler allows Timer2 to increment at the following rates:
1:1, 1:4, 1:16.
POSTSCALER - FREQUENCY DIVIDER:
 The postscaler can be programmed from 1:1 to 1:16 (inclusive).
4KONGUNADU COLLEGE OF ENGINERING AND TECHNOLOGY, TRICHY TIMER2 CONCEPT

5. “TIMER 2 CONCEPT”
THE STRUCTURE OF THE OPTION_REG REGISTER:
 We perform all the necessary settings with T2CON Register The
structure of the T2CON register. The size of the register is 8 bits
INITIALIZING THE OPTION_REG REGISTER:
The following is an example how we can initialize the T2CON
register:
1. TMR2ON=1; // the timer is enable
2. T2CKPS0=0; // Prescaler – 1:1
3. T2CKPS1=0;
4. TOUTPS0=1; // Postscaler – 1:16
5. TOUTPS0=1;
6. TOUTPS0=1;
7. TOUTPS0=1;
Or you can set all the T2CON register at once as follows:
T2CON=0b01111100;
5
KONGUNADU COLLEGE OF ENGINERING AND TECHNOLOGY, TRICHY TIMER2 CONCEPT

6. “TIMER 2 CONCEPT”
BLOCK DIAGRAM OF THE TIMER2 MODULE:
6KONGUNADU COLLEGE OF ENGINERING AND TECHNOLOGY, TRICHY TIMER2 CONCEPT

7. “TIMER 2 CONCEPT”
 Timer2 is an 8-bit timer with a programmable prescaler and
postscaler, as well as an 8-bit period register (PR2).
 Timer2 can be used with the CCP1 module (in PWM mode) as
well as the Baud Rate Generator for the Synchronous Serial Port
(SSP).
 Timer2 is an 8-bit timer with a prescaler and a postscaler. It can be
used as the PWM time-base for PWM mode of the CCP
module(s).
 The TMR2 register is readable and writable, and is cleared on any
device reset.
7KONGUNADU COLLEGE OF ENGINERING AND TECHNOLOGY, TRICHY TIMER2 CONCEPT

8. “TIMER 2 CONCEPT”
PIC TIMER2 formula:
Fout - The output frequency after the division.
Tout - The Cycle Time after the division
4 - The division of the original clock (4 MHz) by 4, when
using internal crystal as clock (and not external oscillator).
Count - A numeric value to be placed to obtain the desired output
Frequency-fuot.
(PR2 – TMR2) - The number of times the counter will count.
8KONGUNADU COLLEGE OF ENGINERING AND TECHNOLOGY, TRICHY TIMER2 CONCEPT

9. “TIMER 0 CONCEPT”
CONCLUSION:
 In this above presentation we can learn about basic concept of
Timer, types of timer, timer2, features, pre and post scaler -
frequency divider clearly.
REFERENCES:
 Mazidi, M.A.,“PIC Microcontroller” Rollin Mckinlay, Danny
causey Printice Hall of India, 2007.
 Ravichandran,C., and Arulaalan,M., “Microcontroller Based
System Design”, Suchitra Publications, Ist edition,2016.
 Dr.Balamurugan.C.R., Periyaazhagar., “Microcontroller Based
System Design”, Megnus Publications, Ist edition,2016.
 Online wikipedia search.
9KONGUNADU COLLEGE OF ENGINERING AND TECHNOLOGY, TRICHY TIMER2 CONCEPT