/* 2014 Roving Dynamics Ltd. Title: RFID Combiner and Printer Control board Rev: 1.0 (Dec 2015) Target MPU = PIC18F2xK22: () CLK = 11.0952Mhz (Use 4xPLL to internally click this up to 44Mhz for better timing) * Description * ----------- * Our HMI PC is located 25M from 2 x RFID readers and a printer, RS232 can only do <10M reliably so we need * to use RS-485. Because we need 4 serial ports and the PIC only has 2 we run 2 soft UART ports to * read the RFID data via an interrupt. The RFID data is only a 10 char string but we also need to * know which one was activated so before we send the string back to the PC we prefix it with an * A or a B (or whatever) data sent from the PC will go directly to the printer port as RS232 however * if we send a prefixed Command string we can optionally make the system switch on/off 4 relays, sound * a buzzer or resend the last RFID strings */ #include #define uint8 unsigned char #define uint16 unsigned short #pragma config FOSC = HSHP // Ext XTAL Running at 11.0592Mhz (reason: common xtal and gives exact 9600 baud rate) #pragma config PLLCFG = ON // PLL x 4 = 44.23Mhz (required for finer timing in interrupt) #pragma config CCP3MX = PORTB5 // check if req #pragma config PBADEN = OFF // ADC OFF (Port B is digital) #pragma config WDTPS = 8192 // Watchdog timer reset timeout = 8 seconds #pragma config WDTEN = ON // Watchdog timer on, will reset chip if I dont reset it within timeout #pragma config STVREN = ON // Stack overflow reset ON (Any stack probs then do a reset. Better safe than sorry!) #pragma config BOREN = ON // Turn on Brown-out reset so the device resets on any power problem // Pin I/O's (changes here will also require change to TRIS in program startup duhh!) #define LED_PC(state) LATCbits.LATC0 = !state // Output (LED Lights when low - hence inverted)) #define LED_PTR(state) LATAbits.LATA4 = !state // Output (LED Lights when low - hence inverted) #define LED_RFID1(state) LATCbits.LATC2 = !state // Output (LED Lights when low - hence inverted) #define LED_RFID2(state) LATCbits.LATC1 = !state // Output (LED Lights when low - hence inverted) #define OC1(state) LATAbits.LATA0 = !state // Output - OC1 relay1 gate #define OC2(state) LATAbits.LATA1 = !state // Output - OC2 relay2 gate #define OC3(state) LATAbits.LATA2 = !state // Output - OC3 relay3 gate #define OC4(state) LATAbits.LATA3 = !state // Output - OC4 relay4 gate #define TX_CTRL(state) LATCbits.LATC4 = state // Output - RD485 - 1 = transmit / 0=receive #define BUZZER(state) LATBbits.LATB4 = state // Output - to buzzer #define RFID1SER !PORTBbits.RB1 // Input - soft UART serial input from RFID 1 #define RFID2SER !PORTBbits.RB2 // Input - soft UART serial input from RFID 2 // use volatile prefix in interrupt variables and/or where you dont want compiler optimising anything. // 9600 bit timings (in units of 7.787uS - value determined by cpu clock and timer 1/3 prescaller) // for soft uart, ie mid-point for sampling bit 1 comes 154us after start bit (this is approximately 20 x 7.787) const uint8 Baud9600[] = {21,38,57,75,93,112,129,147,162}; // we dont time stop bit volatile uint8 PCCommBuf[32]; // serial buffer from UART1 volatile uint8 PTRCommBuf[32]; // serial buffer from UART2 volatile uint8 RFID1CommBuf[16]; // serial buffer from soft UART connected to RFID reader1 volatile uint8 RFID2CommBuf[16]; // serial buffer from soft UART connected to RFID reader2 volatile uint8 PCBufPtr = 0; // volatile uint8 PTRBufPtr = 0; // volatile uint8 RFID1BufPtr = 0; // volatile uint8 RFID2BufPtr = 0; // volatile uint8 SampleBit1 = 0; volatile uint8 SampleBit2 = 0; volatile uint8 t40 = 0; volatile uint16 beeper = 0; // volatile uint16 tone; // enum tHM { ReceiveDataFromPC, SendPrinterDataToPC, SendRFID1DataToPC, SendRFID2DataToPC } HostMode; // state of the main loop // ALL interrupts come here! Keep interrupt code very tight n super fast as only 23uS to process! // so NO loops and NO external proc/function calls! void interrupt high_priority isr(void) { OC1(1); if (INTCON3bits.INT1IF && INTCON3bits.INT1E) // External Interrupt 1: comm detected RFID1. DONT acknowledge flag until stop bit received { LED_RFID1(1); INTCON3bits.INT1E = 0; // disable external int1 until finished processing char and we are ready for next char from RFID1 SampleBit1=0; // going to read in 10 bits, 1 start, 8 data and 1 stop each bit read will inc this byte TMR0L=32; // sync tmr0 interrupt so we dont get one immediately after INTCONbits.TMR0IF = 0; // stop it interrupting if already has TMR1H=0; TMR1L=0; // start timer3 to time the next char in } if (INTCON3bits.INT2IF && INTCON3bits.INT2IE) // External Interrupt 2: comm detected RFID2. DONT acknowledge flag until stop bit received but disable interrupt so stop recurring { LED_RFID2(1); INTCON3bits.INT2IE = 0; // disable external int2 until we have finished processing char and we are ready for next char from RFID2 SampleBit2=0; // going to read in 10 bits, 1 start, 8 data and 1 stop each bit read will inc this byte TMR0L=32; // sync tmr0 interrupt INTCONbits.TMR0IF = 0; // stop it interrupting if already has TMR3H=0; TMR3L=0; // start timer1 to time the next char in } if (PIR1bits.RC1IF) // interrupt is caused by UART 1 RX pin (data received from PC) { LED_PC(1); PCCommBuf[PCBufPtr] = RCREG1; //read the byte from rx register into receive buffer if (PCBufPtr>31) PCBufPtr=0; // inc buffer: if we ever overrun then we wrap around (circular buffer) PIR1bits.RC1IF = 0; // acknowledge/clear rx int flag LED_PC(1); } if (PIR3bits.RC2IF) // interrupt is caused by UART 2 RX pin (data received from printer) { LED_PTR(1); PTRCommBuf[PTRBufPtr] = RCREG2; //read the byte from rx register into receive buffer if (PTRBufPtr>31) PTRBufPtr=0; // inc buffer: if we ever overrun then we wrap around (circular buffer) PIR3bits.RC2IF = 0; // acknowledge/clear rx int flag LED_PTR(1); } if (INTCONbits.TMR0IF) // timer 0 Overflow occurs all the time every 23uS (exact not too important so long as there are about 4 per bit at 9600 baud) { if(INTCON3bits.INT1IF) // RFID1 soft uart { OC2(1); if(TMR1H>Baud9600[SampleBit1]) // wait for next sample window in middle of bit { OC2(0); if(RFID1SER && SampleBit1<8) RFID1CommBuf[RFID1BufPtr] = RFID1CommBuf[RFID1BufPtr] | (1<=8) // received stop byte (8 bits) processed { if(RFID1BufPtr<13) { RFID1BufPtr++; // next char RFID1CommBuf[RFID1BufPtr]=0x0; // clr it INTCON3bits.INT1IE=1; // re-enable interrupt and.. INTCON3bits.INT1IF=0; // clr interrupt flag to wait for next interrupt } } } } if(INTCON3bits.INT2IF) // RFID2 { if(TMR3H>Baud9600[SampleBit2]) // wait for next sample window { if(RFID2SER && SampleBit2<8) RFID2CommBuf[RFID2BufPtr] = RFID2CommBuf[RFID2BufPtr] | (1<=8) // received stop byte (8 bits) processed { if(RFID2BufPtr<13) { RFID2BufPtr++; // next char RFID2CommBuf[RFID2BufPtr]=0; // clr it INTCON3bits.INT2IE=1; // re-enable interrupt and.. INTCON3bits.INT2IF=0; // clr interrupt flag to wait for next interrupt } } } } if(beeper) { if(--t40==0) { t40=40; tone=!tone; // interrupt calling @ 43Khz so too high to just modulate. need to divide to lower the freq of buzzer to around 1Khz beeper--; } BUZZER(beeper && tone); } INTCONbits.TMR0IF = 0; // acknowledge/clr timer0 interrupt } OC1(0); } void delay(uint16 ms) // blocking delay of approx 1000uS (1mS) doesnt need to be accurate, not used for timing (interrupt is used for that) { static uint16 i; while (ms--) { i = 1600; // value tweeked for osc freq of 11.05mhz with 4xPLL = 44Mhz while (i--); } } void Send2PC(uint8 data) // Send byte to pc { TX_CTRL(1); while (!PIR1bits.TX1IF); // wait for tx transmit reg to become free TXREG = data; // send char while (!TXSTA1bits.TRMT); // wait for character to be physically clocked out so we dont overrun transmit buffer } void Send2Printer(uint8 data) // Send byte to printer { while (!PIR3bits.TX2IF); // wait for tx transmit reg to become free TXREG = data; // send char while (!TXSTA2bits.TRMT); // wait for character to be physically clocked out so we dont overrun transmit buffer } uint8 DecodeCMD() // Called from main on serial receive from PC. determine if command { if (PCCommBuf[0] != 'X' ) return 0; // CMD Wake up Sequence is "XW." followed by CMD_Byte if (PCCommBuf[1] != 'W' ) return 0; if (PCCommBuf[2] != '.' ) return 0; // eg "XW.A" in the data from the PC will turn on relay 1 // process cmds if(PCCommBuf[3] == 'A' ) OC1(1); // turn ON relay 1 if(PCCommBuf[3] == 'B' ) OC1(0); // turn OFF relay 1 if(PCCommBuf[3] == 'C' ) OC2(1); // turn ON relay 2 if(PCCommBuf[3] == 'D' ) OC2(0); // turn OFF relay 2 if(PCCommBuf[3] == 'E' ) OC3(1); // turn ON relay 3 if(PCCommBuf[3] == 'F' ) OC3(0); // turn OFF relay 3 if(PCCommBuf[3] == 'G' ) OC4(1); // turn ON relay 4 if(PCCommBuf[3] == 'H' ) OC4(0); // turn OFF relay 4 if(PCCommBuf[3] == 'I' ) beeper=1000; // sound alarm if(PCCommBuf[3] == '1' ) RFID1BufPtr=10; // re-send RFID1 code (if one exists!) if(PCCommBuf[3] == '2' ) RFID2BufPtr=10; // re-send RFID2 code (if one exists!) Send2PC('O'); // Send OK string to PC/Host Send2PC('K'); Send2PC('\r'); Send2PC('\n'); PCBufPtr=0; // empty buffer as we dont want to pass this string through to printer return 1; } int main() { // Init PIC18F2xK22 Registers, peripherals and I/O Ports (See Microchip datasheet for full descriptions) uint8 i; ADCON0 = 0; // Turn off ADC ADCON1 = 0x0F; // turn off ADC ANSELC = 0; // Turn off ADC TRISA = 0x00; // PortA: (00000000) [All Output] TRISB = 0x86; // PortB: (10000110) RB1, RB2, RB7 Inputs, RB0, RB3, RB4, RB5, RB6 Outputs (RB7 is UART RX and must be input)) TRISC = 0x80; // PortC: (10000000) RC7 input, RC0..RC6 output (RC7 is UART RX and must be input) // All outputs to default on POR OC1(0); // relay 1 Off OC2(0); // relay 2 Off OC3(0); // relay 3 Off OC4(0); // relay 4 Off BUZZER(0); // Buzzer off TX_CTRL(0); // RS485 tranceiver in receive mode LED_PC(1); // LED ON LED_PTR(1); // LED ON LED_RFID1(1); // LED ON LED_RFID2(1); // LED ON // now flash leds off in sequence to indicate power up (gives us indication if resetting for any other reasons too) delay(400); LED_PC(0); delay(200); LED_RFID2(0); delay(200); LED_RFID1(0); delay(200); LED_PTR(0); // init state machine HostMode = ReceiveDataFromPC; RFID1BufPtr=0; RFID2BufPtr=0; PCBufPtr=0; PTRBufPtr=0; // interrupts RCONbits.IPEN = 0; // DISABLE PRIORITY INTERRUPTS all use same single ISR (IPEN=0 is actually the default so this line has no effect and left in for comment) INTCON = 0x60; // (0110 0000) Turn on TMR0 interrupt TURN OFF GLOBAL INTERRUPTS until init finished INTCON2 = 0xF4; // (1111 0100) PortB pullups disabled, INT1 + INT2 rising edge, TIMER0 High priority INTCON3 = 0xD8; // (1101 1000) clr INT1 and INT2 flags dont enable interrupts until init finished tho // timers T0CON = 0xc8; // timer0: (1100 1000) 8 bit overflow interrupt occurs every (fOsc/4/prescaler/256) == 11059200 x 4 / 4 / 1 / 256 = 23uS T1CON = 0x45; // timer1: (0100 0101) 16 bit timer fOsc/Prescaler. high timer reg incs every 5.787uS which times our soft uart T3CON = 0x45; // timer3: (0100 0101) same as tmr1 // UART 1 (RS485/PC) SPBRGH1 = 0; // BRG to 9600 baud SPBRG1 = 68; // 68 = 17x4 as we are using 4xPLL on main XTAL TXSTA1bits.BRGH1 = 0; // BRGH=0 TXSTA1bits.TXEN1 = 1; // TX ENABLED TXSTA1bits.SYNC1 = 0; // Async RCSTA1bits.SPEN1 = 1; // Serial port ENABLE (Interrupts enabled in ResetComms() ) PIE1bits.RC1IE = 1; // enable interrupt UART1 // UART 2 (Printer) SPBRGH2 = 0; // BRG to 9600 baud SPBRG2 = 68; // 68 = 17x4 as we are using 4xPLL on main XTAL TXSTA2bits.BRGH2 = 0; // BRGH=0 TXSTA2bits.TXEN2 = 1; // TX ENABLED TXSTA2bits.SYNC2 = 0; // Async RCSTA2bits.SPEN2 = 1; // Serial port ENABLE (Interrupts enabled in ResetComms() ) PIE3bits.RC2IE = 1; // enable interrupt UART2 // turn on all interrupts INTCONbits.GIE = 1; // enable global interrupts while (1) // main program loop { if (HostMode==ReceiveDataFromPC) // default is nothing being sent we are in receive mode waiting for input from PC Host { TX_CTRL(0); // ensure rs485 tranceiver is in receive mode delay(20); LED_RFID1(0); LED_RFID2(0); LED_PTR(0); LED_PC(0); if(PCBufPtr>3) // If chars in PC buffer (UART1), check for command or pass data through to Printer (UART2) { PIE1bits.RCIE = 0; // turn OFF UART interrupts to prevent comm buffer changing while we are processing request if(!DecodeCMD()) Send2Printer(PCCommBuf[PCBufPtr--]); // pass through whats been received from PC to printer (UART1 rx to UART2 tx) PIE1bits.RCIE = 1; // turn ON UART interrupts } else if (PTRBufPtr>4) HostMode=SendPrinterDataToPC; // data coming in from printer rs232 port, so send it else if (RFID1BufPtr > 10) // received a RFID tag so prefix it and send it { HostMode=SendRFID1DataToPC; RFID1CommBuf[0]='A'; RFID1BufPtr--; RFID1CommBuf[RFID1BufPtr++]='\r'; RFID1CommBuf[RFID1BufPtr]='\n'; } else if (RFID2BufPtr > 10) // received a RFID2 tag so prefix it and send it { HostMode=SendRFID2DataToPC; RFID2CommBuf[0]='B'; RFID2BufPtr--; RFID2CommBuf[RFID2BufPtr++]='\r'; RFID2CommBuf[RFID2BufPtr++]='\n'; } } if ( HostMode==SendPrinterDataToPC ) // (shouldnt happen often, but) we are receiving data from Printer UART2 so send it to the PC on UART1 { Send2PC(PCCommBuf[PCBufPtr--]); // send char if(PCBufPtr==0) HostMode=ReceiveDataFromPC; // give up control once sent } if ( HostMode==SendRFID1DataToPC ) // we have received an RFID string so pass it to host PC { for(i=0;i<=RFID1BufPtr; i++) Send2PC(RFID1CommBuf[i]); INTCON3bits.INT1IE=1; // re-enable interrupt and.. INTCON3bits.INT1IF=0; // clr interrupt flag to wait for next interrupt RFID1BufPtr=0; HostMode=ReceiveDataFromPC; // give up control once RFID1 tag sent } if ( HostMode==SendRFID2DataToPC ) // we have received an RFID string so pass it to host PC { for(i=0;i<=RFID2BufPtr; i++) Send2PC(RFID2CommBuf[i]); INTCON3bits.INT2IE=1; // re-enable interrupt and.. INTCON3bits.INT2IF=0; // clr interrupt flag to wait for next interrupt RFID2BufPtr=0; HostMode=ReceiveDataFromPC; // give up control once RFID2 tag sent } ClrWdt(); // run this to stop MPU WDT resetting (Fail safe in case we lock up somewhere above due to crap code!) } }