Discussion in "Project Help" started by    chhabiraj    Feb 4, 2009.
Wed Feb 04 2009, 04:52 AM
I am making project XY recorder using Micro controllerAT89C52.

This my first project .

I don`t know how to decide the value of resistor and capacitor at RESET Pin.

so help me Please.
Wed Feb 04 2009, 02:37 PM

resistor: 8K2, 1/4 watt (8.2K)
capacitor: 10uF,16V

hope you know how the above components are connected to the reset pin.

Wed Feb 04 2009, 03:13 PM
in case if u dont knw plz refer to the image below.....

the LED is optional....

Tags 8051 reset circuit8051 tutorials8051 projects
Tue Feb 10 2009, 12:16 PM
thanx... for your help.

My controller chip is to run at +5 V ..

so that capacitor charging time should be less than the time required by the controller to scan the reset Pin..

Depending on that basic How can I determine the value of resistor and capacitor?
Tue Feb 10 2009, 12:50 PM
sir, as far as i know the values are fixed for all applications..... like they are standard values..... their values donot differ from application to application
Tue Feb 10 2009, 07:40 PM
10uF and 8.2K is generally used, but logic behind this selection is as follows..

Whenpoweris turned on, the circuitholdsthe RSTpin highfor an amountof time that dependson the capacitor valueand the rate at whichit charges.To ensurea valid reset the RSTpin must be held high longenough to allow the oscillator to stsrt up plus two machine cycles.

On power up, VCCshould rise within approximately ten milliseconds.The oscillator start-up time will dependon the oscillatorfrequency.Fora 10MHzcrystal, the start-up timeis typically1rns.For a 1MHzcrystal, the start-up time is typically 10ms.

Inter 8051 Manual

Hope this answered your query I suggest any new student to read Intel Manual for learning 8051.

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Thu Nov 21 2019, 12:30 PM
how to interface 8051 microcontroller with NRF24L01+ module
Sat Oct 12 2019, 10:23 PM
Log in.. then post your code in the 8051 forum
Sat Oct 12 2019, 10:18 AM
Bhadra Sajikumar
i am doing a countdown timer with 8051 for my project, unfortunately our professor had to take a leave of absence before he could teach us most of it.. can someone explain the .asm code of it for me?
Mon Sep 23 2019, 07:37 AM
I am doing a project for my schools wireless security system with cameras,sensors and spot lights using 8051 micro controller, could you help me out with the design and its source code.
Wed Sep 18 2019, 08:48 PM
Caryn Kover
Thank you for your time,
Mon Aug 05 2019, 07:09 PM
@Ismail ..post in forum, give details
Mon Aug 05 2019, 04:33 PM
Ismail balghmi
Hello. Please I won't download
Wed Jul 24 2019, 12:47 AM
@BUSTER123 Please post in the forum
Tue Jul 23 2019, 06:13 PM
hello! newbie here. i am kind of a guy who hates using ready - made existing libraries, so this helped a lot as i was trying to control and write to a character lcd display. however, i can't figure out how to set the cursor position. for example, i want to set it to the 5th column in the first row, so position 5. so according to the table, i am sending 10000101 on the 8 data lines of the lcd (register select pulled low). the cursor does not move there however. and i cant move the cursor left or right too. is it something wrong that i am doing? thank you.
Thu Jul 11 2019, 07:55 PM
@ramos https://www.theengineeringprojects.com/2017/09/l298-motor-driver-library-proteus.html



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