Timer2 in pic16f877a

Timer2 in pic16f877a

5 Pin Count 40 Timers are common features of most microcontroller. The TMR1 register pair (TMR1H:TMR1L) increments from 0000h to FFFFh and rolls over to 0000h. I've tested it using a logic analyzer and Saleae Logic and it really shows that RB2 and RB3 are blinking at the same time. Ele pode ser usado como a base de tempo de PWM para o modo de PWM do módulo CCP. CPU does not know when these  Jun 20, 2014 By using this internal timer which is inbuilt in pic16f877 IC, we can do lots of Now we need to know what are those timer0,timer1 and timer2? The exact values are chip-dependent; e. here is my question: 1)for timer0 i have set intcon<5> to 1 and clear option_reg&lt;5&gt;. Do you get stuck doing PIC timer calculations,juggling between datasheet, calculator and your design requirements? If so then you need some tools to automate the process. PIC16F877 Timer Modules tutorials - Timer0. It takes the form… The General Purpose Android/Arduino Control App. Section 13 . Clone via HTTPS Clone with Git or checkout with SVN using the repository’s web address. . Real Pic Simulator is the fastest software microcontroller simulator targeting the Timer0; Timer1; Timer2; EEPROM read/write and FLASH read; Interrupt-on-  Der Timer2 kann ausschließlich durch den internen PIC-Takt getaktet werden. If the frequency of the oscillator changed, the PWM frequency will also change. Each allows to make additional division of the frequency clock source. In this example the PIC16F877A microcontroller runs with 4MHz crystal oscillator. The servo motor is widely used in model hobbyist such as airplane R/C model for moving the rudder, ailerons, elevators and acceleration control or in the car R/C model for steering and acceleration control. h>. 14 Hz - Period  #include<pic. External, PORTB IOC, Timer0 and Timer1 interrupts with CCS. The fraction of the period for which the signal is on is known as the duty cycle. I understood that timer increments a value in its register according to a prescaler until overflow occurs in which case i PIC Timers with Blinking LED 12 minute read In this post I’ll explain how to operate timers with the PIC microcontroller and give you some examples how they may be used. By continuing to use Pastebin, you agree to our use of cookies as described in the Cookies Policy. TMR2 is a 16-bit Timer2 register which is used to hold the count. It can be used as the El temporizador Timer0 tiene una amplia gama de aplicaciones en la práctica. The Arduino UNO’s ATMega328p has 3 timers at its disposal: Timer0, Timer1 and Timer2. This fact necessarily means that both CCP1 & CCP2 will be restricted to generate PWM signals with the exact same frequency. Of course you have to tell the PIC you want interrupt jump to happen using the  Chapter 2 Microcontrollers and the PIC16F877 … . pic-microcontrollers- programming-in-basic-chapter-03-image-. HIGHLIGHTS. I'm debugging my code but I can't find the reason why RB2 and RB3 are blinking at the same time. e. It has a wide variety of applications such as Digital to Analog Converter (DAC), DC Motor Speed Control, Sine Wave Inverters, Brightness control etc. In this tutorial we are going to discuss the PWM module of PIC16F877A. • PIC16F877A Timer2, CCP • PIC16Fxx reference manual . This is a collection of basic PIC assembly examples for the 16F microcontroller family. but i can't direct the program to go to the interupt PIC16F877A Timer0 module and interrupt PIC16F877A Timer2 module and interrupt The Timer1 module is a 16-bit timer/counter consisting of two 8-bit registers (TMR1H and TMR1L) which are readable and writable. T2CKPS1, T2CKPS0- Timer2 Clock Prescaler bits (selección del rango del divisor del preescalador del Timer2) determina el valor del divisor de frecuencias segun la siguiente tabla: Timer2 is an 8-bit timer with a prescaler, a postscaler, and a period register. PIC16F877A has 3 timer modules, Timer0,Timer1 and Timer2. The calculators below set the Registers for PIC Timers. 000 downloads. the timer0 shows some counting after each cycle. pfodDevice™ and pfodApp™ are trade marks of Forward Computing and Control Pty. The PIC 16F88 has 3 built in timers. No vídeo de hoje vamos começar a estudar o TIMER2, entendendo seu prescaler, postscaler e registrador de comparação PR2. C source, you don't need to worry about the processor includes. Interrupción timer2 AVR, mediante la interrupción timer2 AVR se puede detener el programa Programación de Microcontroladores PIC, AVR, ARDUINO  3 time blocks: Timer0 for 8-bit timer/counter; Timer1 for 16-bit timer/counter; and Timer2: 8-bit The peripheral features include: Two Capture, Compare, PWM  Mar 19, 2005 There are three timers on the PIC16F877: Timer0, Timer1 and Timer2 (there is also a watchdog timer, but it is not typically used to drive  Jun 21, 2018 This project is based on microcontroller PIC16F877A and consists of a of the notes and the CCPR1L the work cycle to 50%; Timer2 module. In case an The Timer2 increments from 00h until it matches PR2 and then resets to 00h on the next increment cycle. They are names as Timer0, Timer1 and Timer2. tw The Timer1 module is a 16-bit timer/counter within most PIC ® MCU devices. Text: Appendix A. Pic16f877a microcontroller is used in the project. Using the prescaler and postscaler at their maximum settings, the overflow time is the same as a 16-bit timer. Below table provides the details of the three Timers. The following steps should be taken when configuring the CCP module for PWM operation: 1. First we learn about the basics of PIC16F877A from the datasheet. PIC Timer calculation. There are two sources that the Timer0 can increase the count. An external 20 Mhz crystal is used as clock source. 2. That would be a good use of your time. Chào các bạn trong bài sẽ hướng dẫn về timer của PIC16F877A. Blog Entry Basic Servo Motor Controlling with Microchip PIC Microcontroller February 17, 2009 by rwb, under Robotics. Apart of this configuration, please could you guide me on how to use only two terminals of the port in such that the first output terminal High (Delay) for about says, 5 sec and off permanently while the other output becomes High permanently after the first terminal goes off. GitHub Gist: instantly share code, notes, and snippets. It can be used as the PWM time base for the PWM mode of the CCP module(s). My PWM works well only if I disable/not initialise Timer0 and Timer1. ru. Section 8. - magkopian/pic-assembly-examples Blood-pressure meter, ups. Lots of us here use XC8 (and MikroC to a lesser extent). thanks to daniel le guern! the rpm meter we will be making is a contact less type, i. The microcontroller PIC16F877A runs with 8MHz crystal oscillator. This article explains how to set up and use the PWM module on almost HC-SR04 Ultrasonic Sensor is one of the best solution for non-contact distance measurement functions and can be easily interfaced with PIC Microcontroller. now we will see one by one. DS39582B-page 3 PIC16F87XA Timer1 can trigger an interrupt when it overflows from FFFFh to 0000h. Before getting into these timers, it is important to understand the concept of Prescalar and Postscaler in a microcontroller. The MCC will automatically generate the code to load the proper registers and  Some PIC® MCU devices only have a Timer2. , for the PIC16F877A values area a . Timer and counter with PIC18F4550. The TImer2 module is an 8-bit timer/counter with the following features: 8-bit timer/counter Readable and writable Software programmable prescaler/PostScaler upto 1:16 Interrupt on overflow from FFh to 00h Timer2 Registers. #include<htc. The 'Include in Source' checkboxes determine whether that Timer will be included in the sample application code shown below the calculators. Timer2. PIC16F877A Timer 1 interrupt: PIC16F887 Timer modules and interrupts. The circuit, when used with any appliance, will maintain the voltage at around 220V even if the input mains voltage varies between 180V and 250V. The device has three readable and writeable hardware timers that can increment automatically each instruction cycle (if no prescaler is used). Timer2 module. Simple example of this  Timer2 is an 8-bit timer which operates in a specific way. • Timer 2 timer only with prescale and postscale. Even same program showing different result. Disable the PWM pin (CCPx) output drivers as an input by setting the associated TRIS bit. I am doing a project on pic16f877A to control dc motor speed control. Distributed by: www. Timer0, Timer1 and Timer2 are essentially counters that increment based on the clock cycle and the timer prescaler. Its intelligence lies in the program on PIC16F877A—a low-cost microcontroller that is readily available. SERVO MOTOR CONTROL USING PIC16F877A (with 20MHz Crystal Oscillator) SERVO MOTOR CONTROL USING PIC16F877A SERVO MOTOR Servo motors are used to control many things as it offers very precise rotation o Here is the circuit of an automatic voltage stabilizer that can be adapted to any power rating. Timer2 is an 8-bit timer with a prescaler and a postscaler. com 1-800-831-4242. Effects of a Reset When the PIC16F877A is reset, the Timer2 and CCP modules are forced off. PIC16F877a has three timers. cgu. PIC16F876, and PIC16F877) covered by this data sheet. The output of Timer 2 can be selected by the SSP module as a baud clock using   This page will help you to configure the PIC TIMER2 and PWM modules, you will also get a ready-to-use C source code (for MikroC compiler). The PIC16F877A PIC MCU has three Timer Modules. Each PIC module, can be controlled by bit switches in various registers. 535 pulses in a single cycle, i. The Timer 0 and Timer 2 are 8-bit Timers and Timer 1 is a 16-bit Timer. The below table shows the registers associated with PIC16f877A Timer0 module. It can be used  The steps include setting up the I/O, Timer 2 and PWM module to make it run. Is this the problem of China Product? Problem # 2: If I use One Digital input and others Analog, then the PIC16F877A will measure/calculate either the Analog one or the Digital one. Problem # 1: The ADC of PIC16F877A is calculating sometimes like 8bit, sometimes like 10bit. . When you create your . • Timer 1 timer/counter with prescale. High-Performance, Enhanced PIC Flash Microcontroller in 40-pin PDIP The PIC16F877A CMOS FLASH-based 8-bit microcontroller is upward compatible with the PIC16C5x, PIC12Cxxx and PIC16C7x devices. 8 Timer 2 … systems programming with the Microchip PIC16F877 microcontroller. Program Memory Type Flash Program Memory (KB) 14 CPU Speed (MIPS) 5 RAM Bytes 368 Data EEPROM (bytes) 256 Digital Communication Peripherals 1-UART, 1-A/E/USART, 1-SPI, 1-I2C1-MSSP(SPI/I2C) Capture/Compare/PWM Peripherals 2 CCP Timers 2 x 8-bit, 1 x 16-bit ADC 8 ch, 10-bit Comparators 2 Temperature Range (C) -40 to 125 Operating Voltage Range (V) 2 to 5. Dazu wird der PIC-Takt zunächst durch 4 geteilt, um den  PIC Timers. - Iniciar el temporizador Timer2 al poner a uno el bit TMR2ON del registro T2CON. for minutes and hours. hi! i'm a beginner in pic16f877a. Chào các bạn trong bài đăng trước mình đã hướng dẫn các bạn về timer0 và trong bài đăng này mình sẽ tiếp tục hướng dẫn các ban về timer1 của PIC16F877A. edu. Timer2 in PIC16F877 is an 8-bit timer with a prescaler and postscaler. • Timer2: 8-bit timer/counter with 8-bit period register, prescaler and postscaler PIC16F877A 2003 Microchip Technology Inc. // do timer1 stuff here. TIMER2 MODULE . 1 - Habilita el funcionamiento del Timer2. Es muy conveniente y fácil de utilizar en programas o subrutinas para generar pulsos de duración arbitraria, en medir tiempo o en contar los pulsos externos Timer2 is an 8-bit timer with a prescaler and a postscaler. 13. PIC16F877A Timer2 interrupt example: This is a simple example which uses Timer2 interrupt to make an LED connected to RB0 blinking at a frequency of 1Hz. Merhaba bugünkü blog konumda Bilgisayar Mühendisliği dersi olan Mikroişlemciler konularından bahsetmeye , yaptığımız uygulama proje ve ödevleri buradan sizlere iletmeye gayret göstereceğim. Me). Xc8 compiler and MPLABx is used for code compilation. The TMR2 register is readable and writable and is cleared on any device Reset. This section of the manual contains the following major  The third and last timer module of the PIC 16F88 is the Timer2 module. PRESCALAR and POSTSCALAR: - Configurar e iniciar el temporizador Timer2: - Poner a cero el bit de bandera de interrupción TMR2IF en el registro PIR1. There are three memory blocks in each of these PIC-. The Timer2 module has an 8-bit register for the counts, the TMR2 register. We provide Technical support and Videos related to different microcontroller and microprocessor like 8085, Arduino, PIC, AVR, ARM, Rasberry PI, etc. This tutorial series aims to provide introduction to PIC18 MCU's Timers. Free Download PIC Timer 0 Module VIDEO LINK Pic16f877a has three indepenndent timer which can be used as timer,Counters or for PWM generation. All timers can cause an interrupt on overflow, and then restart from zero. The 40 pins make it easier to use the peripherals as the functions are spread out over the pins. DS31013A page 13-1. First we will see how to configure the PWM registers to generate signals of required PWM, At the end we will see how to use the ExploreEmdedded PWM library. please send me a possible firmware for this device (timer)to ru6jw@rambler. Because the timer is built into an 8-bit device, the 16-bit timer register is broken into two 8-bit registers and increments similar to an 8-bit timer with 8-bit prescaler. PWM using PIC16F877A: PWM signals can be generated in our PIC Microcontroller by using the CCP (Compare Capture PWM) module. El timer2 PIC solo puede ser utilizado como temporizador no como contador, consta de 8 bits por lo que sus valores pueden aumentar desde 0 a 255, se comentará sobre el timer2 PIC para el PIC16F877A, del que se puede ver y descargar su hoja de datos desde aquí, lo que se comente aquí para el timer2 de este microcontrolador es muy similar para Pulse Width Modulation is the one of the simple and most commonly used technique to produce analog voltages from digital signals. PIC16F877A introduction and features May 20, 2019 August 10, 2015 by Microcontrollers Lab The PIC microcontroller PIC16f877a is one of the most renowned microcontrollers in the industry. Microcontroller Core Features:• * High performance RISC CPU • Only 35 single word instructions to learn • All single cycle instructions except for program branches which are two cycle • Operating speed: DC - 20 MHz clock input DC - 200 ns instruction cycle PIC Microcontrollers PIC16F877a • Timer2: 8-bit timer/counter with 8-bit period register, pre-scaler and post-scaler – A 10-bit ADC with 8 inputs I'm not an experienced programmer and not sure exactly where you want to use your delays in, but I had tried to make a lengthy delay with pic18f4550 but it didnt work, i. Similar to Timer0, these registers can be read or written to at any point. I am using Timer2 for PWM tone generation, and Timer0 and Timer 1 for other interrupt purposes. Timer0 (8-bit timer) Timer1 (16-bit timer) Timer2 (8-bit timer) All Timers can act as a timer or counter or PWM Generation. PWM Timer2 Utilization. Dear friend, I made ??a device in your circuit “Programmable digital timer switch using a PIC microcontroller,” but it does not work in timer mode – on the LSD screen displays your email address. This is an 8-bit counter, which means that it can count from 0 to 255, and then it will loop back to 0. 0 - Deshabilita el funcionamiento del Timer2. Three timer modules of PIC 16F877 are Timer-0, Timer-1 and Timer-2,Timer operation in various modes, Block Diagram. //Timer2 Registers Prescaler= 1 - TMR2 PostScaler = 1 - PR2 = 255 - Freq = 7843. Timer 1 và 0 là 2 loại timer mà chúng ta rất hay sử dụng vì vậy các bạn phải nắm chất về 2 bộ timer này nha. Timer1 module is a 16-bit timer/counter, which means that it consists of two registers (TMR1L and TMR1H). It is used to adjust the period of the PWM signal of the previously mentioned CCP1 module. Help with Timer2 (PIC16F877A) The objectives and my code are attached. In this tutorial we will learn to generate PWM, Pulse Width Modulated waves using CCP module of PIC 16F877A Microcontroller using MPLAB XC8 compiler. void t2delay();. for(i=0;i<675;i++). On PIC16F877, Timer0 is an 8-bit counter whereas Timer1 and Timer2 are 16-bit counters. For getting started, I would recommend XC8. However, it can not generate this very low frequency like 50Hz due to some limitations that I will describe here. However, please I’m one of your readers, concerns this timer. The content and copyrights of the attached material are the property of its owner. I am working for the first time with pic microcontrollers . If , . Many times, we plan and build systems that perform various processes that depend on time Microchip PIC16 / PIC18 PWM Mode. Timer Calculator is a lightweight software which creates timer interrupts code for mikroC™, mikroBasic™ and mikroPascal™. T imer com PIC 16F877A Trata-se de um Timer/Temporizador que pode ser usado para desligar/ligar alguma carga depois de um certo temp Below is a test program in which i uploaded the above settings. In my project i am generating pwm signals and to generate pwm pic uses timer2 . Timer-1 of pic16f877a is used to generate 1 second delay. Timer4 and Timer6 are just duplicates of the Timer2 peripheral. Thanks so much for this hints you have given us. I assume that you’ve a basic information about the timers. Appendix B shows screen captures of the PWM (16XCLK) and data bit timings from the PIC16F877A, PIC16F877A is placed in sleep, Timer2 will not increment and the state of the module will not change. When Timer1 rolls over, the Timer1 Interrupt Flag (TMR1IF) bit of the Peripheral Interrupt 1 Register (PIR1) is set. Arduino timer interrupt programming is possible for each timer, besides providing timing and pulse counting. Suppose the controller is running at 8MHz. TIMER2 15-1 Generating PWM with PIC16F877A PIC Development Board. Timer2 is the PWM time-base when the CCP module(s) is used in the PWM mode. Latter articles will discuss more advance topics such as Compare Mode, PWM and Captures. PIC16F877 Timer Modules tutorials - Timer2. Además este módulo cuenta con un registro de periodo PR2 que marca el valor máximo que puede alcanzar la cuenta del registro TMR2. It is capable of counting up to 65. TIMER2 é um temporizador de 8 bits com um divisor( prescaler ) e um postscaler. Timer2 will start, make the output high, and after 156 clock cycles it will generate an interupt and raise the pin again from whatever state it’s in. • Timer 0 timer/counter with prescale. • Watch Dog Timer . We use cookies for various purposes including analytics. Figure 13-1 shows a block diagram of Timer2. This code  Timer2: 8-bit timer/counter with 8-bit period . PIC16F877 Tutorial on Timer modules. The post divider of timer 2, when used in PWM mode, is irrelevant 10-bit A/D converter module. Timer2 According to the PIC16F877A datasheet, The Timer2 module (timer/counter) has the following features: • 8-bit timer/counter • Readable and writable • 2-bit software programmable prescaler (3-options) • 4-bit software programmable postscaler (16-options) • Internal or external clock select • Interrupt on overflow from FFh to 00h Setting up a PIC timer to the correct frequency can be a tricky business for the uninitiated Software Engineer (i. Pick from over 1000 presets or set the desired parameters manually and hit “Calculate”. Những cấu trúc tiếng Nhật đơn giản tiện lợi よく使われる日本語中級文法 V1(辞書形)+ とおりに、V2 V1(た形)+ とおりに、V2 N の とおりに、V2 Dùng khi đưa ra chỉ thị đối với Khối PWM gồm có 2 mạch so sánh: mạch so sánh 8 bit với mạch so sánh 10 bit. com/timers-pic-microcontroller-delay/ how to use timers of pic microcontroller and generate delay with timer PIC16F877A have 40 pin by 33 path of I/O. Sólo unos pocos programas no lo utilizan de alguna forma. Các bạn chú ý đây là 1 trong các module của PIC16F877A và nó cũng rất quan trọng và được sử dụng rất nhiều nên các bạn phải chú ý để nắm rõ về nó. Veja como configurar a interrupção no timer 2 e entenda o postscaler http://microcontrollerslab. {. This means that it can count up to 255. The first one is the Timer0 module. May 4, 2017 Interrupts stops the CPU program from normal execution and ask it to serve first what appear as a interrupt. To start using a timer we should understand some of the fancy terms like 8-bit/16-bit timer, Prescaler, Timer interrupts and Focs. //if (RE1 == 1) RE1 = 0; // toggle RE1 for scope measurement. Once we understand the Timer 0 it will be easy to work on Timer 1 and Timer 2 as well. 1. The Register values will appear to the right of the settings. The CCPx modules (CCP1 & CCP2) in PWM Mode both are utilizing the Timer2 module as a hardware resource for controlling the timing features of the PWM output signal. - Ajustar el valor de división de frecuencia del temporizador Timer2 por los bits T2CKPS1 y T2CKPS0 del registro T2CON. M. This PIC16F877A microcontroller tutorial answers the question, ” How to use timer0 of PIC16F877A and how to handle its interrupts? “ Using PIC16 simulator (Proteus) you can verify this PIC timer0 code and change it according to your needs. In PIC18F4550, only Timer2 can be used for PWM generation. Ltd. This module is originated to work along with the PWM module of the PIC. Posted Sep 4 2013 by waihung in Microchip PIC with 5 Comments. Pulses generated by the quartz  1997 Microchip Technology Inc. i am trying to make use of timer function (with no external crystal). Basically, a timer is a clock that controls an event sequence at a fixed amount of time. By adding more of this type of timer, a device can  PIC Timer Calculator and Source Code Generator Prescaler. Jameco. Now, on to the final CCS command which sets the time we want the PWM to be high within the period. PIC Timer 0 Module VIDEO LINK Pic16f877a has three indepenndent timer which can be used as timer,Counters or for PWM generation. In this tutorial we will be using the Timer 0 for our application. Many times, we plan and build systems that perform various processes that depend on time. The resolution of our PWM signal is 10-bit, that is for a value of 0 there will be a duty cycle of 0% and for a value of 1024 (2^10) there be a duty cycle of 100%. 3. Jameco Part Number 247038 PIC PWM Calculator and Code Generator. An application can monitor these counters to determine how much time has elapsed. timer0 in pic16f877a. g. Jun 22, 2009 By the way I am already using TIMER2 and TIMER1 for PWM. M PIC Timer0 Code Generator and Calculator shows a Python script which generates PIC Timer0 Source Code in C from parameters calculated in an Excel Spreadsheet which is also shown. THEORY . This calculator will save you from insomnia and headaches ! This page will help you to configure the PIC TIMER2 and PWM modules, you will also get a ready-to-use C source code (for MikroC compiler). In general, timers come very useful for all kinds of applications where precise timing is important, such as digital clocks, stopwatches, alarm clocks or PWM. Generating 50Hz PWM Using PIC16F877A: Hello,For generating PWM signals using PIC microcontroller, we can use the CCP module in it and everything will be easy. I'm currently learning PIC assembly and I have come to the topic of timers. • Prescaler and Postscaler - Timer2 is an 8-bit timer with a prescaler and a postscaler. What should I do for all these timers work together. Servo Motor Control by Using Microcontroller PIC16F877A: PIC16F877A is an easy micro controller for the beginners Here in project: 1) How PIC switches servo motor forward and back ward When we push one switch it goes to positive 90 degree , on second switch it moves backward to negative 90 degree a. I don't know why. void main() T2CON|=(1<<2); //timer2 on. To see how to use PIC16F877A ADC module see the following topic: PIC16F877A ADC example with CCS PIC C compiler PIC16F877A ADC + PWM example CCS C code: A Free PIC Timer 2 calculator - tclet (like a java applet) using the prescaler, postscaler and period register it calculates frequency and period for Timer 2. It’s the most wanted tool on Libstock, with over 63. before the counting starts from zero. Both Timer0 and Timer2 are 8-bit timers (can count from 0 to 255) while Timer1 is a 16-bit timer (0 to 65535). Timer1 can increment up to a value of 65535 before it overflows back to zero. as mentioned above, arduino primo levi if this is a man download pins 9, 10 and 11 can generate pwm signals pic16f877a timer1 interrupt where pin 9 and pin 10 are related with timer1 module (oc1a and oc1b) and pin 11 is related with timer2 module (oc2a) construction of remote El Timer 2 es un temporizador de 8 bits que tiene la particularidad de tener un preescalador y un post-escalador. Posts about PIC16F877A timer written by admin. Aug 27, 2013 Timer2 interrupts here about every 100us if (TMR2IF) {. It converts the analogical signal of the joystick into different digital samples with a resolution of 4,8876 mV/bit. Mạch so sánh 8 bit sẽ so sánh giá trị đếm của timer2 với giá trị của thanh ghi PR2 (period register), giá trị trong timer2 tăng từ giá trị đặt trước cho đến khi bằng giá trị của PR2 thì mạch so sánh sẽ set flip flop RS làm ngõ ra CCPx lên mức 1. Timer2: 8-bit timer - While burning the code in PIC microcontroller their is an acknowledgement received for each code word written in PIC's memory. OK, I Understand PIC18 Timer Progggramming HiHsiao-LChLung Chan Dept Electrical Engineering Chang Gung University, Taiwan chanhl@mail cgu edu twchanhl@mail. thanking you in advanced. Jul 25, 2017 Microchip PIC Family Reference Manuals - Compiled This page is a compiled collection of links to PIC Family Reference . Simple example of this process is the digital wristwatch. There are 3 Timers in PIC16F877A, with timer0 and timer2 as 8-bit timers and timer1 as a 16-bit timer. O registo TMR2 é legível e gravável, e é eliminada em qualquer redefinição do dispositivo. An led is connected at output of port-b pin#4. Pic - Pic18f4550 Pwm. Best regards Wasiliy. This is all that we need for the timer2 because the postscale can stay at 1. while(!TMR2IF);. ErnieM i'm using PIC16F877A and i go through datasheet but could not find any help regarding calculating initial values for Timer2 I know how to calculate initial values for Timer0 but as Timer2 has two scalars (pre/post), kindly advise how can i achieve 1ms delay. So I was pretty happy when I came across this great on-line tool whereby you just type in your oscillator frequency and desired interrupt rate and it generates the setup code for you! PIC Timer Interrupt. In case of PIC16F877 the code word is written one by one and hence their is an acknowledgement required for each code word written and hence the speed of writing is reduced. Description Pulse width modulation (PWM) is a technique of controlling the amount of power delivered to an electronic load using an on-off digital signal. If the TMR2 value is 255 (0xFF) and it is increased once more, it will become 0 (0x00) and the TMR2 interrupt shall be raised. PWM_Freq 1 // 1Khz PWM frequency #define TMR2_PRE 16 //Timer2 Prescale #define PR2_Val   PIC micro controller Interrupts- External Interrupts-Interrupt Programming–Loop time subroutine - Timers-Timer Programming– Front Timer 2 Over Flow. timer2 in pic16f877a