how can i use microcontroller as event counter ?

mc as counter

how can i use microcontroller as event counter,please help

mc as counter

well, videogudu
please tell me what is the microcontroller you use?

Re: mc as counter

iam using 89s8252 microcontroller with 8051 architecture

Re: mc as counter

below is the code for frequency counter...make necessary ammendment according to your requirment

;****************************************************************
;this is for memory Placement
Prog equ 0000h ;Starting address for the program
BitVar equ 0 ;where the Bitsegment starts
DataVar equ 024h ;were the Data Segment starts

;some Constants
T0_MASK equ 0F0h
T1_MASK equ 00Fh

;Symbol definitions used in "main" to control the LCD display.
;not used at all
LCD_CLR equ 01AH ;clear LCD command
LCD_LF equ 0AH ;LCD line feed (next line)
LCD_CR equ 0DH ;LCD carriage return

;some port definitions to make the code more readable
RAM_A16 Bit P5.0
EEP_ENA Bit P5.2
bMode Bit P5.3 ;Check this PortPin to read Mode of op

;Place for data vars
;**************************************************************
DSEG at DataVar ;start at DataSeg
GateTime: DS 1 ;the GateOVCounter
OverFlow: DS 1 ;
frequency: DS 4 ;actually a UINT32 Value
bufindex: DS 1 ;
outbuffer: DS 16
T0Vect: DS 2 ;for saving the actual Irq Vect
T2Vect: DS 2 ;

STACK: DS 1 ;stack starts here

;**************************************************************
BSEG at BitVar ;place first bit here

bReady: dBit 1 ;1: ready for output

;Code starts here
;*****************************************************************
CSEG at Prog ;opens the code segment

ORG Prog + 0
LJMP Init ;should be placed here

CSEG at PROG +0Bh ;Timer 0 overflow interrupt
PUSH T0Vect ;Attention this is very tricky
PUSH T0Vect+1
RET ;ret starts the IRQ

CSEG at PROG+02Bh ;Timer 2 overflow interrupt
PUSH T2Vect ;both Functions need 6 clocks
PUSH T2Vect+1 ;to start the IRQ
RET

CSEG at PROG +100h
Init:
CLR EAL
; SETB RAM_A16 ;Make bit A16 of 128K Ram "high".
; CLR EEP_ENA ;Disable EEPROM.
; CLR P5.1
MOV SP,#STACK-1 ;init the stack V0.1 STACK-1

;since we have a stack now Rest should be placed in Sub routines
Main:
; CALL INIT_LCD ;make all neccesarry LCD Inits
; JB bMode,Main1 ;0 Frequ Mode 1 Period Mode

CALL InitIrqVectorsFreq ;Init Freq Irq Vectors
CALL InitT0Freq ;T0 to Timer Frequency Mode
Call InitT2Freq ;T2 to Counter Mode
SJMP Main2
Main1:
; CALL InitIrqVectorsPeriod
; CALL InitT0Period
; CALL InitT2Period

Main2:

CLR bReady

SETB TR0 ;both Timers are runing
SETB T2I0
SETB EAL
MainLoop:
JNB bReady,$ ;wait for Result
CALL HandleFreqOutput
JMP MainLoop

;DispalyHandler when executing Frequency
HandleFreqOutput:
CLR A
MOV TL0,A
MOV TH0,A ;clear the counter
MOV Overflow,A
MOV GateTime,#20
MOV TL2, # Low (-49999) ;V0.2 new ReloadValue -49999
MOV TH2, # High(-49999)
SETB T2I0
SETB TR0 ;restart both Timers
CLR bReady

;now you have 1 s to format the output as you want
;you will need some 32 Bit Division Functions
;here a short example for doing hex out to a buffer
MOV bufindex,#OutBuffer
CALL BufHexOut

RET

;*****************************************************************************
;subroutines
InitT0Freq:
MOV A, TMOD ;initialize Timer 0 to Counter mode
ANL A, # T0_MASK ;change only T0
ORL A, # 5 ;Mode 1 16 Bit Counter
MOV TMOD,A
CLR A
MOV TL0, A
MOV TH0, A ;Timer0 to zero
SETB ET0 ;allow T0 Irq
RET

InitT2Freq:
MOV GateTime,# 20
MOV T2CON,#00010000b ;0001 0000

MOV CRCL, # Low (-49999) ;0xAF; // 50 ms Reload 3CAF = -50000
MOV CRCH, # High(-49999) ;0x3C;
MOV TL2, # Low (-49999) ;V0.2 new ReloadValue -49999
MOV TH2, # High(-49999)

SETB ET2 ;Interupt Timer 2 enable
; MOV IP, # 20h ;T2 (GateTime) high priority this should be checked
RET ;for 80c535


;*******************************************************************************
;IRQ Functions for frequency measurement only

InitIrqVectorsFreq:
MOV T0Vect+0,# Low (T0FreqIrq) ;T0 for Frequ Counter Mode
MOV T0Vect+1,# High(T0FreqIrq)
MOV T2Vect+0,# Low (T2FreqIrq) ;T2 for Frequ Counter Mode
MOV T2Vect+1,# High(T2FreqIrq)
RET


T0FreqIrq:
INC OverFlow ;count the overflows
RETI

T2FreqIrq:
PUSH PSW
PUSH ACC
DEC GateTime
MOV A,GateTime
JNZ T2FreqIrq1
CLR TR0 ;stop counter
CLR T2I0 ;stop timer we have the freq
SETB bReady ;indicate valid freq value
MOV frequency+0, #0 ;MSB always zero
MOV Frequency+1, Overflow ;MSB-1 overflow
MOV frequency+2, TH0 ;MSB-2
MOV frequency+3, TL0 ;LSB
T2FreqIrq1:
CLR TF2 ;clear always the IRQ Flag
POP ACC
POP PSW
RETI

;example for doing nothing at IRQs
NoVectors:
MOV T0Vect+0,# Low (DoNothingIrq) ;
MOV T0Vect+1,# High(DoNothingIrq)
MOV T2Vect+0,# Low (DoNothingIrq) ;
MOV T2Vect+1,# High(DoNothingIrq)
RET

DoNothingIrq:
RETI

;V0.2

;some example Output Functions
;sends 'f=0xxxxxh Hz' to OutBuffer
BufHexOut:
MOV A,#'f'
CALL BufWriteChar

MOV A,#'='
CALL BufWriteChar

MOV A,frequency+1 ;LSB+2
CALL BufWrite2Digits

MOV A,frequency+2 ;Lsb +1
CALL BufWrite2Digits

MOV A,frequency+3 ;LSB
CALL BufWrite2Digits

MOV A,#'h'
CALL BufWriteChar

MOV A,#' '
CALL BufWriteChar

MOV A,#'H'
CALL BufWriteChar

MOV A,#'z'
CALL BufWriteChar

MOV A,#0 ;end of buffer
CALL BufWriteChar

RET

;sends ACC as 2 Hex Digits to Buffer
BufWrite2Digits:
PUSH ACC
SWAP A
CALL Bin2Hex
CALL BufWriteChar
POP ACC
CALL Bin2Hex
; CALL BufWriteChar
; RET

;Buffer Output Function
BufWriteChar:
; PUSH AR0
MOV R0,bufindex
MOV @R0,A
INC R0
MOV bufindex,R0
; POP AR0
RET

;Return Ascii Equivalent of ACC 0..3
Bin2Hex:
; PUSH DPH
; PUSH DPL
MOV DPTR, # AsciiTab
ANL A,# 0Fh
MOVC A,@A+DPTR
; POP DPL
; POP DPH
RET

AsciiTab:
DB '0'
DB '1'
DB '2'
DB '3'
DB '4'
DB '5'
DB '6'
DB '7'
DB '8'
DB '9'
DB 'A'
DB 'B'
DB 'C'
DB 'D'
DB 'E'
DB 'F'

END