rc5.rar_8051 decoder program_RC5_RC5 PIC c++_decoder rc5_rc5 c++

/* A simple RC5 decoder the demodulator diode is connected to P3.2 (INT0) and T0 is used to recieve the RC5 bits The reload values are based on a 12 MHZ XTAL and on a programmable remote control (EasyTip1 code 718) This remote control uses a slightly differnd timming so for standart timming the reload values have to be adjusted I wrote this because I had to emulate a SAA3049 which is discontinued more infos and some asm code at: http://www.ustr.net/infrared/infrared1.shtml */ #include "AT892051.h" #define UINT8 unsigned char #define UINT16 unsigned int #define UINT32 unsigned long #define INT8 signed char #define INT16 signed int #define INT32 signed long #define HighB(value) ((value >> 8) & 0xFF) #define LowB(value) (value & 0xFF) #define RELOAD -440 // Timming for EasyTip1 Code718 #define FIRST_RELOAD -870 // and XTAL = 12 MHZ #define _TOGGLE 0x80 // Toggle Bit #define _START2 0x40 #define _START1 0x20 typedef struct _BYTE { UINT8 b3; /*msb */ UINT8 b2; UINT8 b1; UINT8 b0; /*lsb */ }BYTES; typedef union _LONGINT { UINT32 l; BYTES b; }LONGUNION; // global vars bit bRC5valid; // 1 after RC5 code was recieved UINT8 command; // command and subaddress UINT8 subaddress; UINT8 slopecount; // counter for RC5 slopes LONGUNION shiftreg; // shiftregister for raw RC5 data //**************************************************************** // Interrrupt for reciever diode // this IRQ starts the meassurement Timer //**************************************************************** void RC5StartIrq(void) interrupt IE0_VECTOR { EX0=0; // disable the IRQ slopecount=27; // we need 27 slopes TH0=HighB(RELOAD); // first reload TL0=LowB(RELOAD); TR0=1; // start messurement Timer TF0=0; ET0=1; // Timer0 Irq } // ************************************************************** // Timerinterrupt, // after 27 slopes the shiftreg contains the RC5 value // und bRC5Valid goes to 1 // ************************************************************** void TimingIrq(void) interrupt TF0_VECTOR using 1 { bit bLevel; bLevel= P3_2; // read level while (slopecount) // max 27 slopes { TR0=0; // T0 stopp TH0=HighB(FIRST_RELOAD); // new reload value TL0=LowB (FIRST_RELOAD); TR0=1; // T0 start if (bLevel) // add the level to the shift value { shiftreg.b.b0=shiftreg.b.b0 | 1; } shiftreg.l = shiftreg.l << 1; slopecount--; return; } TR0=0; // T0 stop ET0=0; // Timer Irq off bRC5valid=1; // } //******************************************************* // decodes the recieved value // and sets command and subbaddress // returns 1 if no error occures // else 0 //******************************************************* bit DecodeRC5Code(void) { UINT8 i; UINT8 b; command=0; subaddress=0; shiftreg.l = shiftreg.l >> 1; for (i=0; i < 6 ; i ++) // first 6 Bit command { b=shiftreg.b.b0 & 0x03; if (b==0x02) command = command | 0x40; else if (b==0x01) command = command & ~0x40; else return 0; command = command >> 1; shiftreg.l = shiftreg.l >> 2; } for (i=0;i < 5;i++) // then 5 Bit subaddress { b=shiftreg.b.b0 & 0x03; if (b ==0x02) subaddress = subaddress | 0x20; else if (b==0x01) subaddress = subaddress & ~0x20; else return 0; subaddress = subaddress >> 1; shiftreg.l = shiftreg.l >> 2; } b=shiftreg.b.b0 & 0x03; if (b==0x02) // Toggle Bit command = command | _TOGGLE; else if (b==0x01) command = command & ~_TOGGLE; else return 0; shiftreg.l = shiftreg.l >> 2; b=shiftreg.b.b0 & 0x03; // Startbit 2 if (b==0x02) command = command & ~_START2; // inverted to command else if (b==0x01) // for extented RC5 (7 Bit Commands) command = command | _START2; else return 0; shiftreg.l = shiftreg.l >> 2; b=shiftreg.b.b0 & 0x03; // Startbit 1 if (b==0x02) subaddress = subaddress | _START1; else if (b==0x01) subaddress = subaddress & ~_START1; else return 0; return 1; // return valid } //******************************************************* // ext.Int0 in slope mode //******************************************************* void InitEx0Irq(void) { EX0=1; IT0=1; IE0=0; } //******************************************************* // both timer in 16 Bit mode // T0 is vor RC5 bittime //******************************************************* void InitTimer(void) { TMOD = 0x11; } void main(void) { InitTimer(); InitEx0Irq(); // ReciverInterupt shiftreg.l=0x02; // startvalue EA=1; while (1) { if (bRC5valid) // if we got a code { bRC5valid=0; if (DecodeRC5Code()) // then test the shiftreg { // here command + subaddress // has a valid RC5 code } shiftreg.l=0x02; // restart the reciever IE0=0; EX0=1; } } }