Master and multi Slaves problem UART

[khanh my]

Hello,

I' using CCS C example of code for UART communication between one Master and one Slave. It's work well.
However, i'm trying now with two Slaves, One Master and i have problem. 2 slave data transmission on the master was wrong
I do not know how to address the slave, Who has successfully share information
code master

#include <16f887.h>


#device *=16 ADC=10
#fuses hs,nowdt,noput,noprotect,nobrownout,nolvp,nocpd,nodebug
#use delay(clock=20000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)
#include <stdio.h>
#include <lcd_lib_4bit.c>

unsigned int8 doc, value,value2,doc2,a;

void hienthi_lcd (void);
void main()
{
   
   delay_us(1000);

   delay_us(1000);
   set_tris_d(0x00);
   set_tris_b(0xff);

   set_tris_c(0xff);   
   set_tris_a(0xff); 
   
   lcd_init();
   
   delay_ms(500);


   while(true)
   {
        
         doc=getchar();
         delay_ms(500);
         doc2=getchar();
         hienthi_lcd ();
   }
}

void hienthi_lcd (){
         lcd_putcmd(line_1);
         lcd_putchar("MASTER");
         lcd_putcmd(line_2);
         printf(lcd_putchar,"H0=%3u H1=%3u",doc,doc2);

}

Slave 1:

#include <16f887.h>
#device adc=10
#fuses hs,nowdt,noput,noprotect,nobrownout,nolvp,nocpd,nodebug
#use delay(clock=20000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)
#include <stdio.h>
#include <lcd_lib_4bit.c>
#define station1 0x00
#bit RB0=0x06.0
#bit RB1=0x06.1
#bit RB2=0x06.2
#bit RB3=0x06.3
unsigned int8 doc, value,a;
void doc_xuli_adc(void);
void hienthi_lcd (void);
void khoitaouart()
{
   setup_uart(9600);
}

void main()
{
   
   delay_us(1000);
   set_tris_d(0x00);
   set_tris_b(0xff);
   set_tris_c(0xff);   
   set_tris_a(0x01);  
   setup_adc_ports(san0);
   setup_adc(adc_clock_internal); 
   lcd_init();
   delay_ms(500);

   khoitaouart();
   while(true)
   {
         doc_xuli_adc();
        
         putc(doc);
         hienthi_lcd ();

   }
}
void doc_xuli_adc () {
   set_adc_channel(0);
   delay_us(10);
   a=read_adc ();
   doc=((float)a*4.88)/10;
}

void hienthi_lcd () {
         lcd_putcmd(line_1);
         lcd_putchar("SLAVE1");
         lcd_putcmd(line_2);
         printf(lcd_putchar,"H1=%3u",doc);
}

slave 2:

#include <16f887.h>
#device adc=10
#fuses hs,nowdt,noput,noprotect,nobrownout,nolvp,nocpd,nodebug
#use delay(clock=20000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)
#include <stdio.h>
#include <lcd_lib_4bit.c>
#define station1 0x01
#bit RB0=0x06.0
#bit RB1=0x06.1
#bit RB2=0x06.2
#bit RB3=0x06.3
unsigned int8 doc2, value,a2;
void doc_xuli_adc2(void);
void hienthi_lcd2 (void);
void khoitaouart2()
{
   setup_uart(9600);
}

void main()
{
   
   delay_us(1000);
   set_tris_d(0x00);
   set_tris_b(0xff);
   set_tris_c(0xff);   
   set_tris_a(0x01);  
   setup_adc_ports(san0);
   setup_adc(adc_clock_internal); 
   lcd_init();
   delay_ms(500);

   khoitaouart2();
   while(true)
   {
         doc_xuli_adc2();
        
         putc(doc2);
         hienthi_lcd2 ();

   }
}
void doc_xuli_adc2 () {
   set_adc_channel(0);
   delay_us(10);
   a2=read_adc ();
   doc2=((float)a2*4.88)/10;
}

void hienthi_lcd2 () {
         lcd_putcmd(line_1);
         lcd_putchar("SLAVE1");
         lcd_putcmd(line_2);
         printf(lcd_putchar,"H1=%3u",doc2);
}

 

[jayanth.devarayanadurga]

How does the devices know which is slave and which is master when you are using UART?