Teephone Exchange and ATMEGA8

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djc

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Hi,

I have a hardware.It operates as exchange.I have no schematic, direct hardware.It has one controller ATMEGA8, 4 74HC589, 4 74HC595,one CD4515 and one cross point switch IC 8816. Regarding connections (SCK),pin 11 from 74HC589 is connected to micro controller PIN 17.(RCK),PIN 12 from 74HC589 is connected to micro controller PIN 18.(SLOAD), PIN 13 from 74HC589 is connected to PIN 19 of micro controller.Serial input pin of 74HC589 i.e. PIN 14 has no connection. (OE)PIN is connected to CD4515 line decoder.First latch clock i.e RCK pin is made high to low, then SLOAD pin is made low to high and then SCK pin is made high to low 8 times to get 8 output bits serially.
There are 4 such 74HC589 and 4 such 74HC595. Each of the output enable pin i.e (OE) pin of 74HC589 and 74HC595 are connected to CD4515 line decoder output. Now there are A,B,C,D as 4 inputs on CD4515 which are connected to micro controller's PIN 2,3,5 and 6. CD4515 decoder inhibit pin is connected to Micro controller's PORTD_2. I have made it logical '0' as mentioned in datasheet.
Now by using various combinations on A,B,C,D input of CD4515 various outputs could be selected as selected output will give logical '0' and will enable particular 74HC589 or particular 74HC595. Now switches are connected on all 4 74hc589 on first 4 parallel inputs i.e. a,b,c,d and opto coupler on rest of the parallel inputs. And LED's and Relays are connected to 74HC595 parallel outputs.
Initially i had to detect the key press, which are connected on 74hc589.When key is pressed output of 589 is logical '0'. Which i detected. Now when key is pressed once led should glow and when pressed 2nd time LED should be OFF. Issue i am facing is if key is continuously pressed then LED is continuously ON and OFF i.e. blinking.My code is as below,
Code:
#include <mega8.h>
#include <delay.h>

#define A  PORTD.1           //right
#define B  PORTD.0
#define D  PORTD.3
#define C  PORTD.4
#define decoder_inhibit  PORTD.2
#define par_sck  PORTB.3
#define par_rck  PORTB.4
#define par_out  PINB.0
#define par_sload  PORTB.5
#define ser_shcp  PORTB.4
#define ser_stcp  PORTB.3
#define ser_ds  PORTB.2
#define test  PORTD.5
//#define test_1  PORTD.7
#define delay_1 20
#define delay_2 30

unsigned char key_status[9],binaryNumber[10];
//bit i_5=1,i_6=1,i_7=1,i_8=1;
int i=0,j=0,a=0,m=0,key_1=0,key_2=0,key_3=0,key_4=0,key_status_1=0,key_status_2=0,key_status_3=0,key_status_4=0;
unsigned int final_1,final_2,final_3,final_4,m_1,m_2,m_3,m_4,m_5,m_6,m_7,m_8,m_9,m_10,m_11,m_12;
unsigned int key_5,key_6,key_7,key_8,key_status_5,key_status_6,key_status_7,key_status_8;
unsigned int key_9,key_10,key_11,key_12,key_status_9,key_status_10,key_status_11,key_status_12;
unsigned int key_13,key_14,key_15,key_16,key_status_13,key_status_14,key_status_15,key_status_16;
bit IC_1=0,IC_2,IC_3,IC_4;
void LED_display(unsigned int data)                      //Function to convert decimal to binary
{
//                            
    i=1;
            for(k=0;k<=8;k++){
                             binaryNumber[i++]= data % 2;
                             data = data / 2;
                             //Data_DS = binaryNumber[i];
                             }

                             for(j = i-1;j> 0;j--){
                             ser_ds = binaryNumber[j];
                             ser_shcp = 1;
                             //delay_us(1);
                             ser_shcp = 0;
                             //delay_us(1);
                             }
                 ser_stcp = 1;
                 //delay_us(1);
                 ser_stcp = 0;
                 delay_us(1000);

}
void main(void)
{


PORTB=0x00;
DDRB=0xFE;

// Port C initialization

PORTC=0x00;
DDRC=0x00;

// Port D initialization

PORTD=0x00;
DDRD=0xFF;



while (1)
      {
      // Place your code here
      j=0,i=0;   
            
                     A = 0;               //1st parallel IC
                     B = 0;
                     C = 1;
                     D = 0;
                     par_rck = 1;
                     delay_us(2);
                     par_rck = 0;
                     
                     par_sload = 0;
                     delay_us(2);
                     par_sload = 1;
                                       
                                        
                                          
                                        par_sck = 1;              //G   Q6
                                        //delay_ms(2);
                                        #asm("nop")            
                                        par_sck = 0;                                     

                                        par_sck = 1;               //F   Q5
                                        //delay_ms(2);
                                        #asm("nop")
                                        par_sck = 0;
                                                                                
                                        par_sck = 1;                //E   Q4
                                        //delay_ms(2);
                                        #asm("nop")
                                        par_sck = 0;                                      
                                        
                                        par_sck = 1;                //D    Q3 
                                        //delay_ms(2);
                                        #asm("nop")
                                        par_sck = 0;
                                        if(par_out==1){
                                        //key_status[4]=1;
                                        }
                                        else{
                                        //key_status[4]=0;
                                        delay_us(1);
                                        key_4++;
                                        }

                                        if(key_4==1){
                                        m_4=0;
                                        
                                        while(m_4<=delay_1){
                                        key_status_4=1;
                                        m_4++;
                                         
                                         }
                                        }
                                        
                                        if(key_4==2){
                                        m_4=0;                                        
                                        while(m_4<=delay_2){
                                            key_status_4=0;
                                            m_4++;                                            
                                          }
                                         key_4=0;
                                        }                                       

                                        par_sck = 1;                //C    Q2 
                                        //delay_ms(2);
                                        #asm("nop")
                                        par_sck = 0;                                      
                                        if(par_out==1){
                                        key_status[5]=1;
                                        }
                                        else{
                                        key_status[5]=0;
                                        delay_us(1);
                                        key_3++;
                                        }

                                        if(key_3==1){
                                        
                                        m_3=0;
                                       
                                        while(m_3<=delay_1){
                                          key_status_3=1;
                                          m_3++;                                          
                                         }
                                        }
                                        
                                        if(key_3==2){
                                        m_3=0;
                                        while(m_3<=delay_2){
                                            key_status_3=0;
                                            m_3++;                                            
                                         }   
                                        key_3=0;
                                        }
                                        
                                        par_sck = 1;                 //B   Q1
                                        //delay_ms(2);
                                        #asm("nop")
                                        par_sck = 0;                                      
                                        if(par_out==1){
                                        key_status[6]=1;
                                        }
                                        else{
                                        //key_status[6]=0;
                                        delay_us(1);
                                        key_2++;
                                        }
                              
                                        if(key_2==1){
                                        m_2=0;                                        
                                        while(m_2<=delay_1){
                                            key_status_2=1;
                                            m_2++;
                                            }
                                        }
                                        
                                        if(key_2==2){
                                        m_2=0;
                                        delay_ms(1);
                                        while(m_2<=delay_2){    
                                            key_status_2=0;
                                            m_2++;                                            
                                         }
                                        key_2=0;
                                        }
                                      
                                        par_sck = 1;                  //A   Q0
                                        //delay_ms(2);
                                        #asm("nop")
                                        par_sck = 0;
                                        if(par_out==1){
                                        key_status[7]=1;
                                        }
                                        else {
                                         key_1++;m_1++;                                     
                                        }
                                        if(key_1==50 ){
                                        
                                        key_status_1=1;;
                                        m_1=0;
                                        key_1=0;
                                        }
                                        
                                        
                                         
                                        
                                       if(key_1==1){
                                        m_1=0;
                                        while(m_1<=delay_1){    
                                            key_status_1=1;
                                            m_1++;
                                            }
                                        }
                                        
                                        if(key_1==2){
                                        m_1=0;
                                        while(m_1<=delay_2){
                                            key_status_1=0;
                                            m_1++;
                                            }
                                        key_1=0;
                                        }
                                        final_1   =   (128*0+64*0+32*0+16*0+8*key_status_4+4*key_status_3+2*key_status_2+1*key_status_1);
                     
                                        A = 1;
                                        B = 0;
                                        C = 1;
                                        D = 0;
                                        IC_1=1;
                                        LED_display(final_1);
               }
}

Here it is not sure that when key is released what will be its status, whether it will be ON or OFF. While loop doesn't work as when key is pressed it doesn't come out of that loop. Can somebody please guide.
 

Hello djc,

submit the schematic for a clear understanding of the connection.

from your description it seems that you are getting continuous input, so the led turns ON and OFF continuously.

may be you have to change the HW logic to configure the latch so that it will give the input only once

Regards
 

Thanx sau_sol,

But i don't have schematic. Thanks for your concern.
 

Hi all,
Can anybody please tell me how to operate the clocks of 74HC589. Because for 8 parallel inputs when i am giving 8 clocks i am missing first bit. I am making load clock low to high and then SCK clock high to low every time and collecting the input. Here is my code.
Code:
void clock_function()
{

                       
//                     par_rck = 1;
//                     #asm("nop")
                     par_rck = 0;    //atmega8 pin18
                     
                     par_sload = 0; //atmega8 pin19
                     #asm("nop")
                     par_sload = 1;
                                       
                                       
                                          
                                        par_sck = 1;      //atmega8 pin17        //G   Q7
                                        #asm("nop")     
//                                        if(par_out==1){
//                                        key_status[7]=1;
//                                        }
//                                        else{
//                                        relay_44=0;
//                                        }                                       
                                        par_sck = 0;  
                                        
                                                                                
                                        par_sck = 1;                //E  Q6
                                        #asm("nop")                                        
//                                        if(par_out==1){
//                                        key_status[6]=1;
//                                        }
//                                        else{
//                                        relay_33=1;
//                                        }                                      
                                        par_sck = 0;
                                        
                                        par_sck = 1;                //E  Q5
                                        #asm("nop")                                        
//                                        if(par_out==1){
//                                        key_status[5]=1;
//                                        }
//                                        else{
//                                        relay_22=1;
//                                        }   
                                        par_sck = 0; 
                                        
                                        par_sck = 1;                //E  Q4
                                        #asm("nop")                                         
//                                        if(par_out==1){
//                                        key_status[4]=1;
//                                        }
//                                        else{
                                        //relay_11=1;
//                                        }       
                                        par_sck = 0;
                                        
                                        par_sck = 1;                //D  Q3 
                                        #asm("nop")
                                        if(par_out==1){
                                        key_status[4]=1;
                                        }
                                        else{
                                        key_4++;
                                        }

                                        if((key_4==200)&& (key_status_44==0)){             
                                        key_status_44=1;
                                        //relay_44=1;
                                        }
                                        if((key_4==400)&& (key_status_44==1)){
                                        key_status_44=0;
                                        //relay_44=0;
                                        key_4=0;
                                        }
                                        par_sck = 0;
                                        
                                        par_sck = 1;                //C    Q2 
                                        #asm("nop")                                                                            
                                        if(par_out==1){
                                        key_status[5]=1;
                                        }
                                        else{
                                        key_3++;
                                        }
                                        if((key_3==200)&& (key_status_33==0)){
                                        key_status_33=1;
                                        //relay_33=1;
                                        }
                                        if((key_3==400) && (key_status_33==1)){
                                        key_status_33=0;
                                        //relay_33=0;
                                        key_3=0;
                                        }
                                        par_sck = 0;  
                   
                                        
                                        par_sck = 1;                 //B   Q1
                                        #asm("nop")                                     
                                        if(par_out==1){
                                        key_status[6]=1;
                                        }
                                        else{
                                        key_2++;
                                        }
                                        if((key_2==200) && (key_status_22==0)){
                                        key_status_22=1;
                                        //relay_22=1;
                                        }
                                        if((key_2==400)&& (key_status_22==1)){
                                        key_status_22=0;
                                        //relay_22=0;
                                        key_2=0;
                                        }
                                        par_sck = 0; 
                        
                                        par_sck = 1;                  //A   Q0
                                        #asm("nop")
                                        if(par_out==1){
                                        key_status[7]=1;
                                        }
                                        else {
                                         key_1++;                                     
                                        }
                                        if((key_1==200)&& (key_status_11==0)){
                                        key_status_11=1;
                                        //relay_11=1;
                                        }
                                         
                                        if((key_1==400)&& (key_status_11==1)){
                                        key_status_11=0;
                                        //relay_11=0;
                                        key_1=0;
                                        }
                                        par_sck = 0;


}
 

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