50mS counter on Timer0 (18F4550 on Lab X1)
RHTimer0.zip
RobertCode:'*************************************************************************** '* Name : RHTimer0.pbp * '* Author : Demon * '* Date : Apr 15 2015 * '* Version : 1.0 * '* Notes : 50mS counter on Timer0 * '* Hardware : PIC 18F4550, 20mhz crystal * '* MeLabs U2 Programmer v4.32 * '* Lab X1 board * '* Software : PIC Basic Pro v2.60C * '* MicroCode Studio Plus v2.2.1.1 * '* MPASM v5.46 * '*************************************************************************** '--- if you use these, you must comment the ones in the .inc file --- @ __CONFIG _CONFIG1L, _PLLDIV_5_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L @ __CONFIG _CONFIG1H, _FOSC_HSPLL_HS_1H @ __CONFIG _CONFIG2L, _PWRT_OFF_2L & _BOR_ON_2L & _BORV_1_2L & _VREGEN_ON_2L @ __CONFIG _CONFIG2H, _WDT_OFF_2H @ __CONFIG _CONFIG3H, _CCP2MX_ON_3H & _PBADEN_OFF_3H & _LPT1OSC_OFF_3H & _MCLRE_ON_3H @ __CONFIG _CONFIG4L, _STVREN_ON_4L & _LVP_OFF_4L & _ICPRT_OFF_4L & _XINST_OFF_4L ;--- Oscillator speed ---------------------------------------------------------- DEFINE OSC 48 ;--- Setup Registers ----------------------------------------------------------- ADCON1 = %00001111 ' A/D CONTROL REGISTER 1 ' Bit 7-6 Unimplemented: Read as ‘0’ ' Bit 5 VCFG1: Voltage Reference Configuration bit (VREF- source) ' 1 = VREF- (AN2) ' 0 = VSS ' Bit 4 VCFG0: Voltage Reference Configuration bit (VREF+ source) ' 1 = VREF+ (AN3) ' 0 = VDD ' Bit 3-0 PCFG3:PCFG0: A/D Port Configuration Control bits: ' 1111 = All digital on Port A ' See datasheet for table INTCON2 = %00000000 ' INTERRUPT CONTROL REGISTER 2 ' Bit 7 RBPU: PORTB Pull-up Enable bit ' 1 = All PORTB pull-ups are disabled ' 0 = PORTB pull-ups are enabled by individual port latch values ' Bit 6 INTEDG0: External Interrupt 0 Edge Select bit ' 1 = Interrupt on rising edge ' 0 = Interrupt on falling edge ' Bit 5 INTEDG1: External Interrupt 1 Edge Select bit ' 1 = Interrupt on rising edge ' 0 = Interrupt on falling edge ' Bit 4 INTEDG2: External Interrupt 2 Edge Select bit ' 1 = Interrupt on rising edge ' 0 = Interrupt on falling edge ' Bit 3 Unimplemented: Read as ‘0’ ' Bit 2 TMR0IP: TMR0 Overflow Interrupt Priority bit ' 1 = High priority ' 0 = Low priority ' Bit 1 Unimplemented: Read as ‘0’ ' Bit 0 RBIP: RB Port Change Interrupt Priority bit ' 1 = High priority ' 0 = Low priority T0CON = %10000011 ' TIMER0 CONTROL REGISTER ' Bit 7 TMR0ON: Timer0 On/Off Control bit ' 1 = Enables Timer0 ' 0 = Stops Timer0 ' Bit 6 T08BIT: Timer0 8-Bit/16-Bit Control bit ' 1 = Timer0 is configured as an 8-bit timer/counter ' 0 = Timer0 is configured as a 16-bit timer/counter ' Bit 5 T0CS: Timer0 Clock Source Select bit ' 1 = Transition on T0CKI pin ' 0 = Internal instruction cycle clock (CLKO) ' Bit 4 T0SE: Timer0 Source Edge Select bit ' 1 = Increment on high-to-low transition on T0CKI pin ' 0 = Increment on low-to-high transition on T0CKI pin ' Bit 3 PSA: Timer0 Prescaler Assignment bit ' 1 = Timer0 prescaler is NOT assigned. Timer0 clock input ' bypasses prescaler. ' 0 = Timer0 prescaler is assigned. Timer0 clock input comes from ' prescaler output. ' Bit 2-0 T0PS2:T0PS0: Timer0 Prescaler Select bits ' 111 = 1:256 Prescale value ' 110 = 1:128 Prescale value ' 101 = 1:64 Prescale value ' 100 = 1:32 Prescale value ' 011 = 1:16 Prescale value ' 010 = 1:8 Prescale value ' 001 = 1:4 Prescale value ' 000 = 1:2 Prescale value ;--- Setup Interrupts ---------------------------------------------------------- INCLUDE "DT_INTS-18.bas" ' Base Interrupt System INCLUDE "ReEnterPBP-18.bas" ' PBP interrupts ASM INT_LIST macro ; IntSource, Label, Type, ResetFlag? INT_Handler TMR0_INT, _EndTimer, PBP, yes endm INT_CREATE ; Creates the interrupt processor ENDASM ;--- Setup Port directions ----------------------------------------------------- TRISA = %00000000 TRISB = %11110000 ' Set columns to input, rows to output TRISC = %00000000 TRISD = %00000000 TRISE = %00000000 ;--- Pins ---------------------------------------------------------------------- Column1 VAR PORTB.4 TimerLed VAR PORTD.1 ;--- Variables (Constants) ----------------------------------------------------- Row1 CON %00001110 ' Set selected row to VSS, others to VDD ;--- Initialize variables ------------------------------------------------------ LOW TimerLed PORTB = Row1 ' Set selected row to VSS, others to VDD ;--- Subroutines --------------------------------------------------------------- goto ProgramStart ' Jump over sub-routines ;---- Start Timer0 ------------------------------------------------------------- StartTimer: TMR0H = 109 ' 50 mS Timer TMR0L = 144 HIGH TimerLed @ INT_ENABLE TMR0_INT ; enable Timer 0 interrupts RETURN ;---- Stop Timer0 -------------------------------------------------------------- EndTimer: LOW TimerLed @ INT_RETURN ;---- Scan only top left button on 4 x 4 keypad -------------------------------- KeypadInput: IF PORTB.4 = 0 THEN ' Column 1 GOSUB StartTimer WHILE PORTB.4 = 0: WEND ENDIF RETURN ;--- Program Start ------------------------------------------------------------- ProgramStart: GOSUB KeypadInput ' Scan button GOTO ProgramStart END
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