/***************************************************************************
Copyright:          Manuel Steins 
known Problems:     none
Description:        512 Ch. DMX Empfang
MCU:                8051
CLK:                16MHz
Compiler:           SDCC
Parameter:
--code-loc 0x0000 --stack-auto --vc --iram-size 128         -8051-
--code-loc 0x0000 --stack-auto --vc --iram-size 256         -8052-
***************************************************************************/
 
#include "8051.h"
 
#define channels        8               // Kanäle
#define startadresse    2               // Startadresse
 
__idata volatile unsigned char dmx_data[channels];      // Array mit Werten
 
volatile unsigned int addr;
 
unsigned char a;                                // Testprog
__xdata __at 0x0000 unsigned char b;            // Testprog extern Ram 0x0000
 
 
//---------------------- UART Interrupt -----------------------------------
 
void serial0 (void) __interrupt 4{
    static signed int rx_count;                     // signed!!!
    static __bit dmx_valid;                         // Startbit 
    static __bit dmx_break;                         // Break 
    static unsigned char temp;
 
    temp =  SBUF;
    RI = 0;                                         // Interrupt Flag
 
    if (RB8 == 1){                                  // Brauchbare Daten empfangen
        if (dmx_break == 1){
            if (dmx_valid == 0){                    // 1. Byte nach break
                if (temp == 0x00){                  // Freigabe
                    dmx_valid = 1;
                }  
                else {                              // kein Startbit
                    dmx_break = 0;
                }               
            }
            else{
                rx_count++;
                if (rx_count == channels){           // alle Kanäle empfangen?
                    dmx_break = 0;                   // Pause
                }
                else if (rx_count >= 0){             // Startadresse erreicht?
                    dmx_data[rx_count] = temp;
                }
            }
        }
     }
    else{
        dmx_valid = 0;
        dmx_break = 1;
        rx_count = -addr;
    }    
}
 
//-------------------------- Main Programm -------------------------------
 
void main (void){
 
    PCON = 0x00;                                    // 64tclk 250 Baud 16MHz
    SCON = 0x98;                                    // Serial Port Mode 2 10011000
    IE |= 0x90;                                     // Enable RX I
    addr = startadresse;                            // Startadresse einlesen
 
    while(1){
        a  = ((0x80&dmx_data[0])>>7);
        a |= ((0x80&dmx_data[1])>>6); 
        a |= ((0x80&dmx_data[2])>>5); 
        a |= ((0x80&dmx_data[3])>>4); 
        a |= ((0x80&dmx_data[4])>>3); 
        a |= ((0x80&dmx_data[5])>>2);
        a |= ((0x80&dmx_data[6])>>1); 
        a |= ((0x80&dmx_data[7]));   
        b = a;
    }
}
 

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