/*
 * filename: udp.c
 *
 * siteplayer connected to an 8051 www.siteplayer.com
 * polls keypad, if different from the last one, then send udp to linux
 * this examples shows keypad, but can be hooked up to door/window
 * magnetic sensors, in Linux, data are entered to a database (MySQL)
 * together with date time stamp that can be retrieve and analyze
 * later on
 * use bit banging for serial UART 9600 because the 8051 UART is already
 * being use to send message to a PC.
 *
 */


#include \mc\8051reg.h

#define LCD *(char*)0x4200
#define CONTROL *(char*)0x0100
#define PORTC *(char*)0x0103
#define KEY *(char*)0x6000;

register unsigned char dummy_char, flag, current_key, temp_key, previous_key;

main()
{

   CONTROL = 0x0f;              /* all port of 8155 output */
   putstr("init...\n");

   current_key = 0;
   temp_key = 1;

   for(;;) {
     do {
       current_key = KEY;
       temp_key = current_key;
       short_delay();
       current_key = KEY;
     }
     while (current_key != temp_key);
       
     
     if (current_key != previous_key) {

       previous_key = current_key;      /* save current key */

       /* write 'A', current_key, 'B' to siteplayer */
       putstr("preparing data starting at address 0...\n");
       dummy_char = 0x92;
       send_serial();
       dummy_char = 0x00;       /* low byte of address */
       send_serial();
       dummy_char = 0x00;       /* high byte of address */
       send_serial();
       dummy_char = 0x41;       /* 'A' */
       send_serial();
       dummy_char = current_key;
       dummy_char &= 0x0f;      /* clear upper nibble */
       dummy_char += 0x30;      /* add hex thirty     */
       send_serial();
       dummy_char = 0x42;       /* 'B' */
       send_serial();

       /* clear area of siteplayer for ack from linux */
       putstr("clearing area of siteplayer for linux ack...\n");
       dummy_char = 0x92;
       send_serial();
       dummy_char = 0x03;       /* low byte of address */
       send_serial();
       dummy_char = 0x00;       /* high byte of address */
       send_serial();
       dummy_char = 0x00;   
       send_serial();
       dummy_char = 0x00;
       send_serial();
       dummy_char = 0x00;  
       send_serial();
 

       /* send udp to linux...\n");  */
       putstr("sending udp to linux...\n");
       dummy_char = 0x50;
       send_serial();
       short_delay();   /* give linux time */

       /* read ack from siteplayer */
       dummy_char = 0xC0;       /* read byte from siteplayer */
       send_serial();
       dummy_char = 0x03;       /* address */
       send_serial();
       get_serial();
       if (dummy_char == 0x41)
         putstr("Ack received...\n");
       else
         putstr("Ack not received...\n");

     }
   }
}

toggle_led() {
  dummy_char = 0x90;    /* send serial command          */
  send_serial();
  dummy_char = 0x14;    /* low byte address             */
  send_serial();
  dummy_char = 0xff;    /* high byte address            */
  send_serial();
  if (flag == 0) {
    dummy_char = 0x00;  /* turn on led                  */
    send_serial();
    flag = 1;
  }
  else {
    dummy_char = 0x01;  /* turn off led                 */
    send_serial();
    flag = 0;
  }
}

send_serial()
{
  asm {
        PUSH A          save accumulator
        PUSH 0          save R0
        PUSH 1          save R1

        MOV     A,dummy_char
putc    CLR     P1.2
        MOV     R0,#45
        DJNZ    R0,*
        MOV     R1,#8
putc1   RRC     A
        MOV     P1.2,C
        MOV     R0,#45
        DJNZ    R0,*
        DJNZ    R1,putc1
        SETB    P1.2
        RRC     A
        MOV     R0,#45
        DJNZ    R0,*

        POP 1
        POP 0
        POP A
        RET
  }  
}

get_serial()
{
  asm {
        PUSH A
        PUSH 0
        PUSH 1

getc    JB      P1.1,*
        MOV     R0,#22
        DJNZ    R0,*
        JB      P1.1,getc
        MOV     R1,#8
getc1   MOV     R0,#45
        DJNZ    R0,*
        MOV     C,P1.1
        RRC     A
        DJNZ    R1,getc1
        MOV     dummy_char,A

        POP 1
        POP 0
        POP A
        RET
  }
}

delay() {
  unsigned int j;
  for(j=0; j<20000; j++);
}

short_delay() {
  unsigned int j;
  for(j=0; j<300; j++);
}