89C51 Assembly Code for Programmable Delay Timer With 16x2 LCD and 4x4 Keypad

dear all

i'm trying to make a programmable delay timer that which can make the delay even from 1 sec to 1 hour for my one of the project where its must.

but the problem is that i should be able to run the program of it as well as in parallel it should get displayed in lcd display.

components used
89c51
16/2 lcd display
4*4 matrix keyboard

required time will be entered through key board, after the delay time given there will be an output thats all.

ports i used here

port 0==lcd display in 8bit mode
port 1==8bit dac 0808
port 2== matrix keyboard
port3== few leds & feedback signals

i'll be thankful if you could help me in assembly, because i don't know C. so i'm doing all these stuffs only with assy. laungauge

please help me to solve this one as earlier as possible

regards
rathinavel (rathinavel0904@gmail.com) 08970981017

Do you have to use 89c51 ?

make a function as delay
void delay()
{
delay(FFFF);
}
whatevere time delay u required .. change in thAT ffff

Comutronics.blogspot.com/

You can extend the code explained on this page for any amount of time...
http://www.electroons.com/8051/electroons/timer_overflow.html

[code lang="c"]

#include
sbit switch = P2^0;
sbit LED = P1^3; // Will lit up only when PB2 is pressed
sbit LED1 = P1^0; // To get toggle every second


volatile unsigned int wait=0;

void timer0(void) interrupt 1
{
wait++;
if(wait>10000) // check if one second is elapsed
{
LED1=~LED1;
wait=0;
}
}

void main(void)
{
switch=1; // P2_0 as input
TMOD=0x02; // Timer0 Mode 2 -> 8 bit auto reload
TH0=0xF6; // Each interrupt generate after a 10msec intervel.
IE=0x82; // Timer0 Overflow Interrupt Enable
TR0=1; // Timer0 ON while(1)
{
if(switch==0)
{
LED=0; // Lit LED
}
else
{
LED=1; // LED Off
} }
}
[/code]

just an FYI: There's a "code" feature on the tool bar above the comment box. It's the last one on the right and it makes your code look like this:

[code lang="c"]
sbit switch = P2^0;

void main(void)
{
switch=1; // P2_0 as input
if(switch==0)
{
LED=0; // Lit LED
}
else
{
LED=1; // LED Off
}
}
[/code]

Much easier to read

Brilliant code where is the lcd code then?? aaah ! Not quite as simples as you thought What port , latching the data, reading back from the lcd and of course , is the lcd in serial or parallel mode What bus arxgitecture areb you using 1 wire bus I2C ??

I think you need to start off with an algorithm and flow chhart myself not to worry some very interesting answers none of which are 100% correct

Hardware diagram
Flow chart
Code

Say no more

yes, because i'm not aware about the other controllers, since i'm a beginner.

dear sir,

in actual i'm doing my program in the (asm). because i have not learnt the c and c++ ,

but there is a good news for u i just reached in this for 30 min. then after i'm struggling to do. please help me.

sorry to say this i don't know how to upload the asm codes via code file attachment

Latina

First of all 89C51 is not an easy device to work with from a beginners point of view

I would choose something like a pic micro device far easier to work with or even Atmel is simpler

Secondly
ASM is not for beginners you can do this in ASM but its extremely difficult and again requires tons and tons of practice

Three
LCD routines can be either 8 bit mode 4 bit mode, serial mode or even one of the other bus protocols
This in itself is a complete lecture on its own and requires that you understand what driver chip for the LCD is

Using each driver chip my friend has its own set of commands HD4470 Compatible is the most common but may not be what you intend to use

See here for more details
http://joshuagalloway.com/lcd.html

Four

If you are going to require a timer which is 1 hour delay you will be looking at timer interrupts and hardware interrupts which are r far easier on PIC devices than they are 89C51

Five

You need to a least draw a circuit diagram and build the actual hardware first before you even think about programming other wise you are going to get so lost you wont even know what day it is never mind hours, seconds or displaying on an LCD , or detecting switches being actuated , debounce routines etc “Very important !!”

Five

Microchip offer a cut down version of C programmer for the Micro chip IDE Source boost also offer a C compiler or on my website are instructions for setting up IDE and downloading C package free for which you can compile free on Atmel range of cpu’s Plus my good friend lots of links to how to make your own programmer

http://www.harrington.force9.co.uk/Projects/Atmel/atmelindex.htm

Six

Having built your hardware you need to construct a flow chart otherwise your code and algorithms wont work and again you will get so lost you will end up tearing your hair out trying to figure out what font to use instruction time what character, where on the LCD you want to print that character to name but a few tiny small problems that your going to have straight away

1. So My Advice is start from scratch
2. Present a circuit
3. Use an easy device and then find out how to output to ports convert dec to ascii and then think about how your project is going to turn out and what system you will be using

Seven
If you choose serial addressing of the LCD then of course that also requires knowledge of bit banging RS232 baud rates and obviously how to receive RS232 Very difficult in assembler

See Mike pedro’s page

http://www.rentron.com/pic.htm

Eight

Finally once done with the above ask question then people can help you

Best of luck

Mark

IS IT POSSIBLE TO TAKE DELAY OF 50 MINUTES DELAY FROM THIS PLEASE TELL ME SIR