If you enable interrupts, then you need an interrupt handler. If you prefer just to monitor the
timer1 overflow flag, then disable global interrupts.
Here's one example of monitoring the timer1 overflow flag without interrupts.
Just replace the LCD port assignments & port settings to match your board. I tested this on
a LAB-X1 board.
Note: You can remove the TOGGLE 0 stuff. I used the output for a scope probe.
If you want to use interrupts, here's another version using ON INTERRUPT,Code:DEFINE OSC 4 DEFINE LOADER_USED 1 '================================================= 'Setting LCD parameters '================================================= ' Define LAB-X1 LCD registers and bits Define LCD_DREG PORTD Define LCD_DBIT 4 Define LCD_RSREG PORTE Define LCD_RSBIT 0 Define LCD_EREG PORTE Define LCD_EBIT 1 Define LCD_COMMANDUS 2000 Define LCD_DATAUS 50 ticker VAR WORD T1LO CON $F1 ' constant values for 10mS timer1 overflows T1HI CON $D8 ' use with 1:1 prescale at 4MHz ticker = 0 ' clear ticker on power-up ADCON1 = 7 ' Set PORTA and PORTE to digital Low PORTE.2 ' LCD R/W line low (W) Pause 1000 ' Wait for LCD to start up '================================================= 'Initialisation of PORT's '================================================= PORTB = 0 TRISB=%11110000 OPTION_REG.7=0 'Enable Pull-Up's on PORTB T1CON = 0 '1:1 prescale, internal clock PIE1.0 = 1 'enables the tmr1 overflow interrupt PIR1.0 = 0 'resets tmr1 interrupt flag INTCON.6 = 0 'disable peripheral interrupts INTCON.7 = 0 'disable global interrupts '================================================= 'Main Program '================================================= pause 500 'initialise LCD LCDOUT $FE, 1, "Hello" LCDOUT $FE, $C0, "World" pause 2000 'displays the above for 5 seconds LCDOUT $fe,1 LCDOUT "-- press button" TMR1H = T1HI ' load timer1 for 10mS interrupts TMR1L = T1LO waitforstart: if PORTB.5 = 0 then LCDOUT $FE, 1, "Timer started" T1CON.0 = 1 'starts timer goto loop endif goto waitforstart loop: ' loop waiting for timer1 overflow WHILE PIR1.0=0 ' timer1 overflow? WEND ' no, keep waiting PIR1.0 = 0 ' clear overflow flag TOGGLE 0 ' 10mS pulse on RB0 ticker = ticker + 1 ' inc ticker LCDout $FE,$C0,DEC5 ticker ' display ticker ' timer1 is still ticking, so we'll stop it, then add ' in our value for 10mS interrupts T1CON.0 = 0 ' stop timer1 TMR1L = TMR1L + T1LO ' add in low byte IF TMR1L < T1LO THEN ' did low byte overflow? TMR1H = TMR1H + 1 ' yes, increment high byte ENDIF TMR1H = TMR1H + T1HI ' no, just add in high byte T1CON.0=1 ' start timer1 GOTO Loop END
Once you understand how these work, you can go for the big guns, and use Darrel Taylors'Code:DEFINE OSC 4 DEFINE LOADER_USED 1 '================================================= 'Setting LCD parameters '================================================= ' Define LAB-X1 LCD registers and bits Define LCD_DREG PORTD Define LCD_DBIT 4 Define LCD_RSREG PORTE Define LCD_RSBIT 0 Define LCD_EREG PORTE Define LCD_EBIT 1 Define LCD_COMMANDUS 2000 Define LCD_DATAUS 50 ticker VAR WORD T1LO CON $F1 ' constant values for 10mS interrupts with T1HI CON $D8 ' timer1 1:1 prescale and 4MHz osc ticker = 0 ' clear ticker on power-up ADCON1 = 7 ' Set PORTA and PORTE to digital Low PORTE.2 ' LCD R/W line low (W) Pause 1000 ' Wait for LCD to start up '================================================= 'Initialisation of PORT's '================================================= PORTB = 0 TRISB=%11110000 OPTION_REG.7=0 'Enable Pull-Up's on PORTB T1CON = 0 '1:1 prescale, internal clock PIE1.0 = 1 'enables the tmr1 overflow interrupt PIR1.0 = 0 'resets tmr1 interrupt flag INTCON.6 = 1 'enables all unmasked peripheral interrupts INTCON.7 = 1 'enables global interrupts '================================================= 'Main Program '================================================= pause 500 'initialise LCD LCDOUT $FE, 1, "Hello" LCDOUT $FE, $C0, "World" pause 2000 'displays the above for 5 seconds LCDOUT $fe,1 LCDOUT "-- press button" TMR1H = T1HI ' load timer1 for 10mS interrupts TMR1L = T1LO waitforstart: if PORTB.5 = 0 then LCDOUT $FE, 1, "Timer started" T1CON.0 = 1 'starts timer goto loop endif goto waitforstart ON INTERRUPT goto BasicInt loop: ' loop waiting for interrupt & display updates @ NOP GOTO Loop ' update & display ticker on each interrupt DISABLE BasicInt: TOGGLE 0 ' toggle RB0 every 10mS ticker = ticker + 1 ' increment ticker LCDout $FE,$C0,DEC5 ticker ' display ticker ' timer1 is still ticking, so we'll stop it, then add ' in our value for 10mS interrupts T1CON.0 = 0 ' stop timer1 PIR1.0 = 0 ' clear overflow flag TMR1L = TMR1L + T1LO ' add in low byte IF TMR1L < T1LO THEN ' did low byte overflow? TMR1H = TMR1H + 1 ' yes, increment high byte ENDIF TMR1H = TMR1H + T1HI ' no, just add in high byte T1CON.0=1 ' start timer1 RESUME ENABLE END
instant interrupts here http://www.picbasic.co.uk/forum/showthread.php?t=3251
Then you'll really start having fun...;o}
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