| 0,0 → 1,135 |
|---|
| #nolist |
| //#define PTT PIN_A2 // PTT control |
| //#define TXo PIN_C0 // To the transmitter modulator |
| #define PERIODAH delay_us(222) // Halfperiod H 222;78/1200 500;430/500 |
| #define TAILH delay_us(78) |
| #define PERIODAL delay_us(412) // Halfperiod L 412;345/1200 1000;880/500 |
| #define TAILL delay_us(345) |
| #byte STATUS = 3 // CPUs status register |
| |
| byte SendData[16] = {'A'<<1, 'L'<<1, 'L'<<1, ' '<<1, ' '<<1, ' '<<1, 0x60, |
| 'C'<<1, 'Z'<<1, '0'<<1, 'R'<<1, 'R'<<1, 'R'<<1, 0x61, |
| 0x03, 0xF0}; |
| |
| boolean bit; |
| int fcslo, fcshi; // variabloes for calculating FCS (CRC) |
| int stuff; // stuff counter for extra 0 |
| int flag_flag; // if it is sending flag (7E) |
| int fcs_flag; // if it is sending Frame Check Sequence |
| int i; // for for |
| |
| void flipout() //flips the state of output pin a_1 |
| { |
| stuff = 0; //since this is a 0, reset the stuff counter |
| if (bit) |
| { |
| bit=FALSE; //if the state of the pin was low, make it high. |
| } |
| else |
| { |
| bit=TRUE; //if the state of the pin was high make it low |
| } |
| } |
| |
| void fcsbit(byte tbyte) |
| { |
| #asm |
| BCF STATUS,0 |
| RRF fcshi,F // rotates the entire 16 bits |
| RRF fcslo,F // to the right |
| #endasm |
| if (((STATUS & 0x01)^(tbyte)) ==0x01) |
| { |
| fcshi = fcshi^0x84; |
| fcslo = fcslo^0x08; |
| } |
| } |
| |
| void SendBit () |
| { |
| if (bit) |
| { |
| output_high(TXo); |
| PERIODAH; |
| output_low(TXo); |
| PERIODAH; |
| output_high(TXo); |
| PERIODAH; |
| output_low(TXo); |
| TAILH; |
| } |
| else |
| { |
| output_high(TXo); |
| PERIODAL; |
| output_low(TXo); |
| TAILL; |
| }; |
| } |
| |
| void SendByte (byte inbyte) |
| { |
| int k, bt; |
| |
| for (k=0;k<8;k++) //do the following for each of the 8 bits in the byte |
| { |
| bt = inbyte & 0x01; //strip off the rightmost bit of the byte to be sent (inbyte) |
| if ((fcs_flag == FALSE) & (flag_flag == FALSE)) fcsbit(bt); //do FCS calc, but only if this |
| //is not a flag or fcs byte |
| if (bt == 0) |
| { |
| flipout(); |
| } // if this bit is a zero, flip the output state |
| else |
| { //otherwise if it is a 1, do the following: |
| if (flag_flag == FALSE) stuff++; //increment the count of consequtive 1's |
| if ((flag_flag == FALSE) & (stuff == 5)) |
| { //stuff an extra 0, if 5 1's in a row |
| SendBit(); |
| flipout(); //flip the output state to stuff a 0 |
| }//end of if |
| }//end of else |
| // delay_us(850); //introduces a delay that creates 1200 baud |
| SendBit(); |
| inbyte = inbyte>>1; //go to the next bit in the byte |
| }//end of for |
| }//end of SendByte |
| |
| void SendPacket(char *data) |
| { |
| bit=FALSE; |
| |
| fcslo=fcshi=0xFF; //The 2 FCS Bytes are initialized to FF |
| stuff = 0; //The variable stuff counts the number of 1's in a row. When it gets to 5 |
| // it is time to stuff a 0. |
| |
| // output_low(PTT); // Blinking LED |
| // delay_ms(1000); |
| // output_high(PTT); |
| |
| flag_flag = TRUE; //The variable flag is true if you are transmitted flags (7E's) false otherwise. |
| fcs_flag = FALSE; //The variable fcsflag is true if you are transmitting FCS bytes, false otherwise. |
| |
| for(i=0; i<10; i++) SendByte(0x7E); //Sends flag bytes. Adjust length for txdelay |
| //each flag takes approx 6.7 ms |
| flag_flag = FALSE; //done sending flags |
| |
| for(i=0; i<16; i++) SendByte(SendData[i]); //send the packet bytes |
| |
| for(i=0; 0 != *data; i++) |
| { |
| SendByte(*data); //send the packet bytes |
| data++; |
| }; |
| |
| fcs_flag = TRUE; //about to send the FCS bytes |
| fcslo =fcslo^0xff; //must XOR them with FF before sending |
| fcshi = fcshi^0xff; |
| SendByte(fcslo); //send the low byte of fcs |
| SendByte(fcshi); //send the high byte of fcs |
| fcs_flag = FALSE; //done sending FCS |
| flag_flag = TRUE; //about to send flags |
| SendByte(0x7e); // Send a flag to end packet |
| } |
| |
| #list |