DT Instant Interrupts help

[perides]

Thanks...
Compiled and worked (not I was expected), but there´s my fault.

Before interrupts, with a 25Hz signal I´ve read a 1500 rpm.
Now, with led blinking, I´ve read is 120~180.

The code

'****************************************************************
'*  Name    : UNTITLED.BAS                                      *
'*  Author  : Mauro Perides                                     *
'*  Notice  : Copyright (c) 2008 Mauro Perides                  *
'*          : All Rights Reserved                               *
'*  Date    : 25/11/2008                                        *
'*  Version : 1.0                                               *
'*  Notes   :                                                   *
'*          :                                                   *
'****************************************************************
'@ device pic16F887, HS_OSC, WDT_OFF, LVP_OFF
INCLUDE "DT_INTS-14.bas"     ' Base Interrupt System
INCLUDE "ReEnterPBP.bas"     ' Include if using PBP interrupts

'Define MHZ Crystal
DEFINE OSC 20
' Set LCD 
DEFINE LCD_DREG	PORTB
' Set starting Data bit (0 or 4) if 4-bit bus
DEFINE LCD_DBIT	0
' Set LCD Register Select port
DEFINE LCD_RSREG	PORTB
' Set LCD Register Select bit
DEFINE LCD_RSBIT	4
' Set LCD Enable port
DEFINE LCD_EREG	PORTB
' Set LCD Enable bit
DEFINE LCD_EBIT	5
' Set LCD bus size (4 or 8 bits)
DEFINE LCD_BITS	4
' Set number of lines on LCD
DEFINE LCD_LINES	2
' Set command delay time in us
DEFINE LCD_COMMANDUS	2000
' Set data delay time in us
'DEFINE LCD_DATAUS	50

SYMBOL LED1 = portd.1
symbol rpmIn = portd.0
rpm VAR word

ASM
INT_LIST  macro    ; IntSource,        Label,  Type, ResetFlag?
        INT_Handler   TMR1_INT,  _ToggleLED1,   PBP,  yes
    endm
    INT_CREATE               ; Creates the interrupt processor
ENDASM

T1CON = $31                ; Prescaler = 8, TMR1ON
@ INT_ENABLE  TMR1_INT     ; enable Timer 1 interrupts



:main
    CM1CON0 = 0 ' Comparators off (Do I need these?)
    CM2CON0 = 0 ' Comparators off
    'ANSEL = 0
    ANSELH = 0  ' Configure other AN pins as digital I/O

    output PORTB
    INPUT PORTD.0

    PORTC = 0
    TRISC = 0
    
    
    LCDOUT $FE, 1,   "    prdTURBO    "
    LCDOUT $FE, $C0, "  FUEL COMPUTER "
    pause 2000
    LCDOUT $FE, 1
    
    
    while 1=1
     COUNT rpmIn, 100, rpm 
     LCDOUT $FE,1, "PULS/S ", DEC(RPM)
     LCDOUT $FE, $C0, "RPM ", DEC(rpm)*60
    wend

 
'---[TMR1 - interrupt handler]--------------------------------------------------
ToggleLED1:
     TOGGLE LED1
@ INT_RETURN

[Acetronics2]

Hi,

Just disable interrupts before and re-enable them after the "COUNT" command ... but issue expected if blinking the Led @ more then 5 Hz ...

Note you do not need interrupts to blink your Led ... COUNT in a loop gives a correct ( read convenient enough ) timebase !!!


Alain

[Ioannis]

Hi. I would recommend for the sake of experimantation to increase the sampling of the count command to say 2000msec and see what happens.

The timer1 interrupts the count every 105 msec and is obvious that there is interference since the Count also samples at 100 msec. Remember that the Interrupts are not Instant with the exact meaning. There is an overhead to save and restore the variables and program counter.

Also at your program:

:main

make it as

main:

and

    while 1=1
     COUNT rpmIn, 100, rpm 
     LCDOUT $FE,1, "PULS/S ", DEC(RPM)
     LCDOUT $FE, $C0, "RPM ", DEC(rpm)*60
    wend

make it as:

rpm var word
LCDOUT $FE,1, "PULS/S ", $FE,$C0,"RPM:"
    while 1=1
     COUNT rpmIn, 2000, rpm:rpm=rpm*60 
     LCDOUT $FE, $80,dec,"  ", rpm,$FE,$C5, DEC rpm,"   "
    wend

this is much faster.

Ioannis

[Acetronics2]

Hi,

W/ no interrupts using ...

....


    while 1
     TOGGLE LED1
     COUNT rpmIn, 100, rpm 
     LCDOUT $FE,2, "PULS/S ", DEC(RPM ), "            "
     LCDOUT $FE, $C0, "RPM ", DEC(rpm)*60 , "                 "
    wend

END

so simple as that ... ( LCDOUT spaces avoid resetting the LCD ... which is toooooooo long ! )

... BTW : How many pulses per rev. ???

Alain

[perides]

Hi...

Working fine now. Thanks for the directions.

I know I don´t need interrupts to just blink a led (and don´t need for most of things). Just to see how it works.

In future I expect this code will read some sensors (pressure, air temp, rpm and a pot), do some calculation and provide near exact extra fuel needed for an aftermarkt turbo charged engine runing at high revs. At this time I think that I´ll need interrups, since in this case, time is critical

... BTW : How many pulses per rev. ???

Don´t know yet... need to check. Using 1 at this time.

[perides]

Can´t figure by myself .
Can someone explain me tachometer maths??
Engine will run up to 5500 revs. 1 pulse for revolution.