rds_link2.c

RDS应用实例

//-------------------------------------------------------------------------
// RDS Decoding
// COPYRIGHT (C) 2003, Enbia Technology Inc.
// Target: 8031
// AUTHOR: STEVEN LUO
//
// Revision History:
// 2003/2/16 - Original Version
//-------------------------------------------------------------------------
#include <reg51.h>
#include <types.h>
#include <intrins.h>
#include <bin.h>

//#define DEBUG

// Gloables ------------------ //
WORD PICode;				//
BYTE GroupType;				//
BYTE PTY;					//
BOOL bTP;					// TP
BOOL bMS;					// M/S
BOOL bTA;					// TA

BOOL bRDSOk = 0;			// set when group 0 ready
BOOL bTextOk = 0;			// set when group 2 ok, Text ready, need 16 groups

extern WORD aRDS_Text[32];	// radio text 
extern WORD aPS[4];			// Service name, 8 chars


// Locals ------------------- //
static WORD aRDS_Block[4];	// Groupe = 4 blocks
static WORD rdsdata[2];		// byte 1, byte 2
							// 0 0 0 0 0 0 c9 c8 c7 c6 c5 c4 c3 c2 c1 c0
static WORD crc;
static BYTE pscnt;
static BYTE textcnt;

#ifdef DEBUG
	sbit PIN_RDS_DATA = P3^1;	// using 89c51
	sbit PIN_TEST = P3^7;		
#else
	sbit PIN_RDS_DATA = P3^7;	// using 89c2051
	sbit PIN_TEST = P1^7;		
#endif

//-------------------------------------------------------------------------
// RDS Callback
//-------------------------------------------------------------------------
void RDS_BLOCK_Auto_Update(void){			
BYTE chr_addr;
static BOOL bTextAB = 0;

	PICode = aRDS_Block[0];					
	GroupType = (aRDS_Block[1] >> 11) & 0x1f;	
	PTY = (aRDS_Block[1] >> 5) & 0x1f;		

	switch (GroupType){						
		case 0:	// Group 0A					
		case 1: // Group 0B					
			bTP = aRDS_Block[1] & 0x0400;		// bit 10
			bTA = aRDS_Block[1] & 0x0010;		// bit 4
			bMS = aRDS_Block[1] & 0x0008;		// bit 3			

			chr_addr = aRDS_Block[1] & 0x03;
			if (chr_addr == 0) pscnt = 0; else pscnt ++;
			if (chr_addr == pscnt) aPS[chr_addr] = aRDS_Block[3]; else bRDSOk = 0;
			if (pscnt == 3) bRDSOk = 1;
			break;

 		case 4:	// Group 2A
			// if TextAB changed, should update
			if (bTextAB != (aRDS_Block[1] & 0x10)){		// Text AB : bit 5 in block 1
				bTextAB = (aRDS_Block[1] & 0x10);
				textcnt = 0; 
			}

			chr_addr = aRDS_Block[1] & 0x0f;

			if (chr_addr == 0) textcnt = 0; else textcnt ++;
			if (chr_addr == textcnt) {
				aRDS_Text[chr_addr] = aRDS_Block[2]; aRDS_Text[chr_addr + 1] = aRDS_Block[3]; 
				// if "0x0d" found, the text finish.
				if (((aRDS_Text[chr_addr] & 0x00ff) == 0x000d) || ((aRDS_Text[chr_addr] & 0xff00) == 0x0d00) || ((aRDS_Text[chr_addr+1] & 0x00ff) == 0x000d) ||	((aRDS_Text[chr_addr+1] & 0xff00) == 0x0d00)){
					bTextOk = 1; textcnt = 0; 
				}
	  		}
			else { 
				bTextOk = 0;
			}
			if (textcnt >= 16) {bTextOk = 1; textcnt = 0;}
			break;		

		case 5: // Group 2B					
			chr_addr = aRDS_Block[1] & 0x0f;
			if (chr_addr == 0) textcnt = 0; else textcnt ++;
			if (chr_addr == textcnt) {
				aRDS_Text[chr_addr] = aRDS_Block[2]; 
				// if "0x0d" found, the text finish.
				if (((aRDS_Text[chr_addr] & 0x00ff) == 0x000d) || ((aRDS_Text[chr_addr] & 0xff00) == 0x0d00)){
					bTextOk = 1; textcnt = 0; 
				}
		  	}
			else { 
				bTextOk = 0;
			}
			if (textcnt >= 16) {bTextOk = 1; textcnt = 0;}
			break;		

		default: 
			break;						
	}	
}


// --------------------------------------------------------------
// RDS_CRCCheck
// --------------------------------------------------------------
void RDS_CRCCheck(void){
bit bCFlag;
BYTE TempH, TempL;

	TempH = rdsdata[0] / 0x100;
	TempL = rdsdata[0] % 256;

	//C9
	ACC = TempH & 0x7c;
	bCFlag = P;
	ACC = TempL & 0x3e;
	bCFlag ^= P;
	if(bCFlag)crc = 0x200;

	//C8
	ACC = TempH & 0x3e;
	bCFlag = P;
	ACC = TempL & 0x1f;
	bCFlag ^= P;
	if(bCFlag) crc |= 0x100;

	//C7
	ACC = TempH & 0x63;
	bCFlag = P;
	ACC = TempL & 0x31;
	bCFlag ^= P;
	if(bCFlag) crc |= 0x80;

	//C6
	ACC = TempH&0xcd;
	bCFlag = P;
	ACC = TempL & 0xa6;
	bCFlag ^= P;
	if(bCFlag)crc |= 0x40;

	//C5
	ACC = TempH & 0xe6;
	bCFlag = P;
	ACC = TempL & 0xd3;
	bCFlag ^= P;
	if(bCFlag)crc |= 0x20;

	//C4
	ACC = TempH & 0x8f;
	bCFlag = P;
	ACC = TempL & 0x57;
	bCFlag ^= P;
	if(bCFlag) crc |= 0x10;

	//C3
	ACC = TempH & 0x3b;
	bCFlag = P;
	ACC = TempL & 0x95;
	bCFlag ^= P;
	if(bCFlag)crc |= 0x08;

	//C2
	ACC = TempH & 0xe1;
	bCFlag = P;
	ACC = TempL & 0xf4;
	bCFlag ^= P;
	if(bCFlag)crc |= 0x04;

	//C1
	ACC = TempH & 0xf0;
	bCFlag = P;
	ACC = TempL & 0xfa;
	bCFlag ^= P;
	if(bCFlag) crc |= 0x02;

	//C0
	ACC = TempH & 0xf8;
	bCFlag = P;
	ACC = TempL & 0x7d;
	bCFlag ^= P;
	if(bCFlag) crc |= 0x01;
}

// -------------------------------------------------- //
#define OFFSET_A			0x00fc			// 0x00fc
#define OFFSET_B			0x0198			// 0x0198
#define OFFSET_C			0x0168			// 0x0168
#define OFFSET_C2			0x0350			// 0x0350
#define OFFSET_D			0x01b4			// 0x01b4
// --------------------------------------------------------------
// Interrupt Handle Routines
// --------------------------------------------------------------
// ISREX0:EXTERNAL INTERRUPT 0 SERVICE ROUTINE 
static void ISREX0() interrupt 0{
static BYTE seq = 0;
static BOOL bSynch = 0;
static BYTE bitcnt;

	PIN_TEST = 1;

	rdsdata[0] <<= 1; if (rdsdata[1] & 0x0200) rdsdata[0] |= 0x0001;
	rdsdata[1] <<= 1;
	if (PIN_RDS_DATA) rdsdata[1] |= 0x0001; else rdsdata[1] &= 0x03fe;
	
	rdsdata[1] &= 0x03ff;
	
	bitcnt ++; 	

	if (!bSynch){
		crc = 0;
		RDS_CRCCheck();		// Input = rdsdata[0], output = crc;
		crc ^= rdsdata[1];

		if (crc == OFFSET_A){
			seq = 1; bSynch = 1; bitcnt = 0; aRDS_Block[0] = rdsdata[0];  
		}
	}
	else if (bitcnt == 26){
		bitcnt = 0;

		crc = 0;
		RDS_CRCCheck();		// Input = rdsdata[0], output = crc;
		crc ^= rdsdata[1];

		// -------------------------- Syn Checking ----------------------- //
		if ((crc == OFFSET_A) && (seq == 0)){
			seq = 1; aRDS_Block[0] = rdsdata[0];  
		}
		else if ((crc == OFFSET_B) && (seq == 1)){
			seq = 2; aRDS_Block[1] = rdsdata[0]; 
		}
		else if ((crc == OFFSET_C) && (seq == 2)){
			seq = 3; aRDS_Block[2] = rdsdata[0]; 
		}
		else if ((crc == OFFSET_C2) && (seq == 2)){
			seq = 3; aRDS_Block[2] = rdsdata[0]; 
		}
		else if ((crc == OFFSET_D) && (seq == 3)){
			seq = 0; aRDS_Block[3] = rdsdata[0]; 
			RDS_BLOCK_Auto_Update();
		}
		else {	// Lost sychronization
			bSynch = 0; bRDSOk = 0; bTextOk = 0;
		}
	}					

	PIN_TEST = 0;
}