Steve, below is the code. Some of the code is redundant at the moment but when I get over this stumbling block I will be using the remainder of the code for data logging to a pc using visual basic. You will see the timer interrupt code at about line 65 or so that I am using.

Thanks again to you and all that have continued to offer help and support. I really appreciate it.

Seamus.




$MOD52


;DIGITAL FREQUENCY CONNECTED TO P2.0
;
;***************************************
;* CONSTANT DEFINITIONS *
;***************************************

;Stack size (initial value of SP register)
StackAddr EQU 0E0H ;stack address (equals size)

;HD44780 (LCD Controler) Definitions
ClrScr EQU 01H ;clear screen
SetDDRam EQU 80H ;set ddram address
LCDLineLength EQU 20 ;lcd's line length
LCDRowsNum EQU 4 ;lcd's max.row number

;TMRCYCL EQU 12
;TMR_SEC EQU CRYSTAL/TMRCYCL ; = 921600
;TWNTYTH EQU TMR_SEC * #.05 ; = 46080
;RSET_TM EQU 65536-TWNTYTH ; = 19456
RSET_TM EQU 19456

LED EQU P3.4
LCDDATA EQU P0
MINUTES EQU 07DH
SECONDS EQU 07Eh
TICKS EQU 07Fh ;End of internal RAM

DSEG AT 30H
LCD_1: DS 20 ;lcd display buffer

lcdenable BIT P3.7 ;enable signal for lcd display
lcdread BIT P3.6 ;read signal for lcd
lcdreg BIT P3.5 ;RS when H switch to command register, when L to data register
lcdbusy BIT P0.7 ;data line 7 od lcd, for busy state testing

CSEG

;***************************************
;* INTERRUPT VECTORS *
;***************************************
ORG 0H
AJMP InitProc ;reset
ORG 3H
AJMP IrqExt0 ;int0
ORG 0BH
AJMP IrqTmr0 ;timer 0
ORG 13H
AJMP IrqExt1 ;int1
ORG 1BH
AJMP IrqTmr1 ;timer 1
ORG 23H
AJMP IrqSPI ;spi
ORG 30H

IrqExt0: RETI ;external int0

;***************************************
;* TIMER 0 INTERRUPT *
;***************************************
IrqTmr0:
PUSH ACC
CLR TR0 ;Turn off timer0 as we reset the value
MOV TH0,#HIGH RSET_TM ;Set the high byte of the reset value
MOV TL0,#LOW RSET_TM ;Set the low byte of the reset value
SETB TR0 ;Restart timer0
DJNZ TICKS,EXIT_TMR0 ;Decrement TICKS
MOV TICKS,#20 ;Reset TICKS

CALL ClearLCD

;;REAL TIME CLOCK CODE
CALL RTC

;;FOR TESTING PURPOSES
CPL LED

;;SETS UP SOME VARIABLES FOR LCD POSITION
MOV R1,#0 ;row no.0
MOV R2,#0 ;column no.0

;;INCASE WE HAVE NO SIGNAL
MOV A,R6
JNZ SIGNAL ;HAS R6 A VALUE?
MOV A,R7
JNZ SIGNAL ;IS R7 NOT ZERO
MOV DPTR,#NoSignal0
CALL WriteCString
JMP EXIT_TMR0 ;EXITS

SIGNAL:
;;16-BIT SUBTRACT! -- THIS NEEDS TO BE MADE INTO A FUNCTION
;;HIGH IN->R6,R7 -- LOW IN->R4,R5 -- ANS->R2,R3
; SETB RS1
; MOV A,#194 ;Move the low-byte into the accumulator
; CLR C ;Always clear carry before first subtraction
; SUBB A,07h ;Subtract the second low-byte from the accumulator
; MOV R3,A ;Move the answer to the low-byte of the result

; MOV A,#1 ;Move the high-byte into the accumulator
; SUBB A,06h ;Subtract the second high-byte from the accumulator
; MOV R2,A ;Move the answer to the low-byte of the result

; MOV 07H, R3
; MOV 06H, R2
; CLR RS1

;;CONVERT HEX TO ASCII
CALL Hex3DecConv ;result in r5,6,7
CALL Dec2AsciiConv ;result in lcd_1 (ram memory buffer)
MOV R0,#LCD_1 ;r0 contains address of ram buffer

;;MOVE ADDRESS OF LCD_1 5 SPACES TO THE RIGHT
; MOV A,R0
; ADD A,#5
; MOV R0,A

;;MANUALLY DISPLAY TEMPERATURE ON LCD!
;;R1->ROW -- R2->COL -- R3 -- ASC
; MOV R3,#43
; CALL PutCharOnLCD

MOV A,@R0
MOV R3,A
INC R2
CALL PutCharOnLCD

INC R0

MOV A,@R0
MOV R3,A
INC R2
CALL PutCharOnLCD

INC R0

MOV A,@R0
MOV R3,A
INC R2
CALL PutCharOnLCD

INC R0

MOV A,@R0
MOV R3,A
INC R2
CALL PutCharOnLCD

INC R0

MOV A,@R0
MOV R3,A
INC R2
CALL PutCharOnLCD

INC R0

MOV A,@R0
MOV R3,A
INC R2
CALL PutCharOnLCD

INC R0

MOV A,@R0
MOV R3,A
INC R2
CALL PutCharOnLCD

INC R0

MOV A,@R0
MOV R3,A
INC R2
CALL PutCharOnLCD

; INC R0
;
; MOV A,@R0
; MOV R3,A
; INC R2
; CALL PutCharOnLCD

; MOV R3,#46
; INC R2
; CALL PutCharOnLCD
; INC R0
; MOV A,@R0
; MOV R3,A
; INC R2
; cALL PutCharOnLCD
;' INC R2
;' MOV DPTR,#Degrees
;' CALL WriteCString
; MOV R3,#0
; INC R2
; CALL PutCharOnLCD
; MOV R3,#'C'
; INC R2
; CALL PutCharOnLCD


;;INCASE OF NO SIGNAL, THIS WILL RESET VALUES
MOV R5,#0
MOV R6,#0
MOV R7,#0

EXIT_TMR0:
POP ACC
RETI ;Returns!

;***************************************
;* OTHER INTERRUPTS *
;***************************************

;external int1
IrqExt1: RETI

;timer 1 interrupt
IrqTmr1: RETI

;spi interrupt
IrqSPI: RETI

;***************************************
;* MAIN PROGRAM CODE *
;***************************************
InitProc:

MOV SP,#StackAddr ;stack pointer setting
CALL InitLCD ;lcd init - 8 bit interface
; CALL DefChars
;;TIMER STUFF!
MOV TH0,#HIGH RSET_TM ;Initialize timer high-byte
MOV TL0,#LOW RSET_TM ;Initialize timer low-byte
MOV TMOD,#21h ;Sets up Timer0 for normal use, timer1 for baud
MOV TCON,#01h
MOV TH1,#0FDh ;sets for 9600 baud
MOV SCON,#50h ;sets sm1 only
SETB TR1 ;Off goes Timer1
SETB TR0 ;Off goes Timer0

;;INTERRUPT STUFF!
MOV TICKS,#60 ;Ticks from 60 down for three Seconds
SETB EA ;Initialize interrupts
SETB ET0 ;Initialize Timer 1 interrupt

MOV 0Fh,#0 ;R7 BANK 1 - I FORGET WHY I DID THIS.
MOV R5,#0
MOV R6,#0
MOV R7,#0
MOV SECONDS,#0
MOV MINUTES,#0


;;SOME COPYLEFT INFORMATION
MOV R1,#0 ;row no.0
MOV R2,#0 ;column no.0
MOV DPTR,#CopyLeft0
CALL WriteCString
MOV R1,#1 ;row no.1
MOV R2,#0 ;column no.0
MOV DPTR,#CopyLeft1
CALL WriteCString


CLR P2.0
DETECT:
JNB P2.0,$
MOV TH2,#0
MOV TL2,#0
SETB TR2
JB P2.0,$
CLR TR2
MOV R6,TH2
MOV R7,TL2
MOV R5,#0
SJMP DETECT

;***************************************
;* REAL TIME CLOCK CODE *
;***************************************
RTC:
INC SECONDS
MOV A,SECONDS ;Move the seconds variable into the accumulator
CJNE A,#60,EXIT_RTC
MOV SECONDS,#0
INC MINUTES
EXIT_RTC:
SETB RS1 ;as not to disturb other registers
; MOV R4,0 ;reset them just in case
; MOV R5,0
; MOV R6,0
MOV R7,SECONDS
CALL Hex3DecConv
CALL Dec2AsciiConv ;result in lcd_1 (ram memory buffer)
;;MOVE ADDRESS OF LCD_1 6 SPACES TO THE RIGHT
MOV R0,#LCD_1 ;r0 contains address of ram buffer
MOV A,R0
ADD A,#6
MOV R0,A
;;SET UP LCD POSITION AND WRITE SECONDS, ':', AND MINUTES
MOV R1,#1
MOV R2,#14
CALL WriteAString
MOV R2,#13
MOV R3,#58
CALL PutCharOnLCD
; MOV R4,0
; MOV R5,0
; MOV R6,0
MOV R7,MINUTES
CALL Hex3DecConv
CALL Dec2AsciiConv ;result in lcd_1 (ram memory buffer)
MOV R0,#LCD_1 ;r0 contains address of ram buffer
MOV A,R0
ADD A,#6
MOV R0,A
MOV R1,#1
MOV R2,#11
CALL WriteAString
CLR RS1
RET


;***************************************
;* LIBRARY FUNCTIONS/CODE *
;***************************************

;Out data to status control register (of LCD)
;status control register is using to input control codes for lcd controller
OutStatRegLCD: CLR lcdreg ;choose status register
CLR lcdread ;& write mode
NOP
SETB lcdenable
MOV P0,A ;move acc.content to P2
CLR lcdenable ;data latched by enable signal
PUSH ACC
CALL CheckBusyFlag
POP ACC
RET

;Display char at cursor position
;this routine outputs char contained in acc. to video ram of lcd
OutLCD: SETB lcdreg ;choose data register
CLR lcdread ;& write mode
NOP
SETB lcdenable
MOV P0,A ;move acc.content to P2
CLR lcdenable ;data latched by enable signal
PUSH ACC
CALL CheckBusyFlag
POP ACC
RET

;Delay instead of busy line checking
;if you want, you can check the value of P0.7 (d7 of lcd)
;logic H on this line is for BUSY state of lcd controller
CheckBusyFlag:
SETB lcdenable
CLR lcdreg
SETB lcdread
MOV LCDDATA,#0FFh
MOV A,LCDDATA
JB ACC.7,CheckBusyFlag
CLR lcdenable
CLR lcdread
RET

;Initializing of lcd (8 bitów)
InitLCD:
CLR lcdreg
CLR lcdread
CLR lcdenable
SETB lcdenable ;enable H, then L
MOV P0,#30H
CLR lcdenable
SETB lcdenable ;enable H, then L
MOV P0,#30H
CLR lcdenable
SETB lcdenable ;enable H, then L
MOV P0,#30H
CLR lcdenable
MOV A,#3CH
CALL OutStatRegLCD
MOV A,#08H
CALL OutStatRegLCD
MOV A,#01H
CALL OutStatRegLCD
MOV A,#06H
CALL OutStatRegLCD
MOV A,#0CH ;lcd "on display"
CALL OutStatRegLCD
RET

;DefChars: CLR A ;start address of CGRAM
; ORL A,#40H ;cgram definition mode (b6=1)
; CALL OutStatRegLCD
; MOV DPTR,#Char ;start address of definition to dptr
;DefChars1: CLR A
; MOVC A,@A+DPTR ;byte from def.table to acc.
; CJNE A,#0,DefCharsSkip1 ;is it the end of table?
; JMP DefCharsSkip2
;DefCharsSkip1: CALL OutLCD ;send a byte
; INC DPTR ;next position
; JMP DefChars1
;DefCharsSkip2: MOV A,#80H ;display mode
; CALL OutStatRegLCD
; RET


;;CLEAR LCD SCREEN
ClearLCD:
MOV A,#ClrScr ;"clear screen" code
CALL OutStatRegLCD
RET


;display char on lcd
;R1 <- row number (0 - n)
;R2 <- column number (0 - n)
;R3 <- ascii char code (code of character from rom char.generator of lcd)
PutCharOnLCD: PUSH ACC

CLR TI
MOV SBUF,R3
JNB TI,$

MOV A,R1 ;save r1
MOV 10h,A
CJNE R1,#1,PutCharOn1 ;is row=1?
MOV A,#64 ;yes,ddram start position=64
JMP PutCharOffset
PutCharOn1: CJNE R1,#2,PutCharOn2 ;is row=2?
MOV A,#20 ;yes,ddram start pos.=20
JMP PutCharOffset
PutCharOn2: CJNE R1,#3,PutCharOn3 ;is row=3?
MOV A,#84 ;yes,ddram start pos.=84
AJMP PutCharOffset
PutCharOn3: CLR A ;if row=0 then ddram start pos.=0
PutCharOffset: ADD A,R2 ;offset for x coordin.
ORL A,#SetDDRam ;set ddram
CALL OutStatRegLCD
PutCharOffSkip:
MOV A,R3
CALL OutLCD ;Out char on screen
MOV A,10h ;R1 recall
MOV R1,A
POP ACC
RET

;r1= row number
;r2=column number
;dptr=string address
WriteCString: CLR A
MOVC A,@A+DPTR ;chacter code from rom to acc.
CJNE A,#0,WriteCSkip1 ;is it the end of string
RET
WriteCSkip1: MOV R3,A
CALL PutCharOnLCD ;put char on lcd
INC R2 ;next column
CJNE R2,#LCDLineLength,CStringSkip2 ;is it max column?
MOV R2,#0 ;yes,clear column number
INC R1 ;next row
CJNE A,#LCDRowsNum,CStringSkip2 ;is max row number?
MOV R1,#0 ;yes-clear row number
MOV R2,#0 ;&column,start from home pos.
CStringSkip2: INC DPTR ;next chacter
AJMP WriteCString



;write a string from ram memory
;R0=address of string in ram memory
;R1=row number
;R2=column number
WriteAString:
MOV A,@R0 ;first char from ram position to acc.
CJNE A,#0,WriteASkip1 ;is it the end code?
RET
WriteASkip1: MOV R3,A
MOV A,R0 ;ro save
PUSH ACC
CALL PutCharOnLCD ;display char.
POP ACC ;r0 restore
MOV R0,A
INC R2 ;next column
CJNE R2,#LCDLineLength,AStringSkip2 ;is it max number of column?
MOV R2,#0 ;yes,clear column number
INC R1 ;and go to the next row
CJNE A,#LCDRowsNum,AStringSkip2 ;is it the max number of row?
MOV R1,#0 ;yes,clear row number and
MOV R2,#0 ;go to the first row
AStringSkip2: INC R0 ;increment pointer address
JMP WriteAString

;3 bytes of hex number to decimal convertion routine
;number in r5,r6,r7 (r5-msb,..,r7-lsb), result in r4,r5,r6,r7
;the routine counts, how many times you can subtract the 1000000 from numer, then 100000,10000,1000,100,10,1
;each counter equals position of decimal number f.e.:
; 1E74 hex - you can subtract 1000 seven (7) times, 100 seven (7) times, 10 nine (9) times and the rest
;is six (6), so your result of conversion is 7796 (equals 1E74)
Hex3DecConv: CLR C
MOV R4,#0 ;milion counter clear

Hex3DecLoop1: MOV A,R7 ;how many time we can subtract 10000000 without carry (989680H)
SUBB A,#80H
MOV R7,A
MOV A,R6
SUBB A,#96H
MOV R6,A
MOV A,R5
SUBB A,#98H
MOV R5,A
JC Hex3DecSkip1
INC R4
JMP Hex3DecLoop1
Hex3DecSkip1: MOV A,R4
PUSH ACC ;push counter onto stack
MOV A,R7
ADD A,#80H
MOV R7,A
MOV A,R6
ADDC A,#96H
MOV R6,A
MOV A,R5
ADDC A,#98H
MOV R5,A
CLR C
MOV R4,#0
Hex3DecLoop2: MOV A,R7 ;how many times we can subtract 1000000 (F4240H) without carry
SUBB A,#40H
MOV R7,A
MOV A,R6
SUBB A,#42H
MOV R6,A
MOV A,R5
SUBB A,#0FH
MOV R5,A
JC Hex3DecSkip2
INC R4
JMP Hex3DecLoop2
Hex3DecSkip2: MOV A,R4
PUSH ACC ;push counter onto stack
MOV A,R7
ADD A,#40H
MOV R7,A
MOV A,R6
ADDC A,#42H
MOV R6,A
MOV A,R5
ADDC A,#0FH
MOV R5,A
CLR C
MOV R4,#0
Hex3DecLoop3: MOV A,R7 ;100000 (186A0H)?
SUBB A,#0A0H
MOV R7,A
MOV A,R6
SUBB A,#86H
MOV R6,A
MOV A,R5
SUBB A,#01H
MOV R5,A
JC Hex3DecSkip3
INC R4
JMP Hex3DecLoop3

Hex3DecSkip3: MOV A,R4
PUSH ACC ;onto stack
MOV A,R7
ADD A,#0A0H
MOV R7,A
MOV A,R6
ADDC A,#86H
MOV R6,A
MOV A,R5
ADDC A,#01H
MOV R5,A

Hex2DecConv: MOV R4,#0
CLR C
Hex2DecLoop1: MOV A,R7 ;10000 (2710h)?
SUBB A,#010H
MOV R7,A
MOV A,R6
SUBB A,#27H
MOV R6,A
MOV A,R5
SUBB A,#0
MOV R5,A
JC Hex2DecSkip1
INC R4
JMP Hex2DecLoop1
Hex2DecSkip1: MOV A,R4 ;onto stack
PUSH ACC
MOV A,R7
ADD A,#010H
MOV R7,A
MOV A,R6
ADDC A,#27H
MOV R6,A

CLR C
MOV R4,#0
Hex2DecLoop2: MOV A,R7 ;1000 (3E8h)?
SUBB A,#0E8H
MOV R7,A
MOV A,R6
SUBB A,#03H
MOV R6,A
JC Hex2DecSkip2
INC R4
JMP Hex2DecLoop2
Hex2DecSkip2: MOV A,R4 ;onto satck
PUSH ACC
MOV A,R7
ADD A,#0E8H
MOV R7,A
MOV A,R6
ADDC A,#03H
MOV R6,A

CLR C
MOV R4,#0
Hex2DecLoop3: MOV A,R7 ;100 (64h)?
SUBB A,#064H
MOV R7,A
MOV A,R6
SUBB A,#0H
MOV R6,A
JC Hex2DecSkip3
INC R4
JMP Hex2DecLoop3
Hex2DecSkip3: MOV A,R4 ;onto stack
PUSH ACC
MOV A,R7
ADD A,#064H
MOV R7,A
MOV A,R6
ADDC A,#0H
MOV R6,A

CLR C
MOV R4,#0
Hex2DecLoop4: MOV A,R7 ;10 (0Ah)?
SUBB A,#0AH
MOV R7,A
JC Hex2DecSkip4
INC R4
JMP Hex2DecLoop4
Hex2DecSkip4: MOV A,R4 ;onto stack
PUSH ACC
ADD A,#0AH ;1

MOV A,R7 ;tens & ones in w R7
ADD A,#0AH
MOV R7,A
POP ACC
SWAP A
ADD A,R7
MOV R7,A
POP ACC ;thousands & hundreds in R6
MOV R6,A
POP ACC
SWAP A
ADD A,R6
MOV R6,A
POP ACC ;tens thousands & hundreds thousands in R5
MOV R5,A
POP ACC
SWAP A
ADD A,R5
MOV R5,A
POP ACC ;milins & tens milions in R4
MOV R4,A
POP ACC
SWAP A
ADD A,R4
MOV R4,A
RET

;Decimal to ascii conversion
;decimal in r4(msb),r5,r6,r7(lsb),result in ram buffer LCD_1(0..7)
;note:numbers are in correct order after hex2dec conversion routine
;routine takes each of decimal number (4 bits of 8 bit register) and adds it to 0 ascii code character
;f.e. 15 => '0'+1 -> '1' , '0'+5 -> '5'

Dec2AsciiConv:
MOV A,#LCD_1
MOV R0,A ;pointer to lcd_1
MOV A,R4
ANL A,#0F0H
SWAP A
ADD A,#'0'
MOV @R0,A
INC R0
MOV A,R4
ANL A,#0FH
ADD A,#'0'
MOV @R0,A
INC R0
MOV A,R5
ANL A,#0F0H
SWAP A
ADD A,#'0'
MOV @R0,A
INC R0
MOV A,R5
ANL A,#0FH
ADD A,#'0'
MOV @R0,A
INC R0
MOV A,R6
ANL A,#0F0H
SWAP A
ADD A,#'0'
MOV @R0,A
INC R0
MOV A,R6
ANL A,#0FH
ADD A,#'0'
MOV @R0,A
INC R0
MOV A,R7
ANL A,#0F0H
SWAP A
ADD A,#'0'
MOV @R0,A
INC R0
MOV A,R7
ANL A,#0FH
ADD A,#'0'
MOV @R0,A
INC R0 ;put the end of string code
MOV A,#0
MOV @R0,A
RET

;====================================================================
; subroutine UDIV16
; 16-Bit / 16-Bit to 16-Bit Quotient & Remainder Unsigned Divide
;
; input: r1, r0 = Dividend X
; r3, r2 = Divisor Y
;
; output: r1, r0 = quotient Q of division Q = X / Y
; r3, r2 = remainder
;
; alters: acc, B, dpl, dph, r4, r5, r6, r7, flags
;====================================================================

UDIV16: mov r7, #0 ; clear partial remainder
mov r6, #0
mov B, #16 ; set loop count

div_loop: clr C ; clear carry flag
mov a, r0 ; shift the highest bit of
rlc a ; the dividend into...
mov r0, a
mov a, r1
rlc a
mov r1, a
mov a, r6 ; ... the lowest bit of the
rlc a ; partial remainder
mov r6, a
mov a, r7
rlc a
mov r7, a
mov a, r6 ; trial subtract divisor
clr C ; from partial remainder
subb a, r2
mov dpl, a
mov a, r7
subb a, r3
mov dph, a
cpl C ; complement external borrow
jnc div_1 ; update partial remainder if
; borrow
mov r7, dph ; update partial remainder
mov r6, dpl
div_1: mov a, r4 ; shift result bit into partial
rlc a ; quotient
mov r4, a
mov a, r5
rlc a
mov r5, a
djnz B, div_loop
mov a, r5 ; put quotient in r0, and r1
mov r1, a
mov a, r4
mov r0, a
mov a, r7 ; get remainder, saved before the
mov r3, a ; last subtraction
mov a, r6
mov r2, a
ret

; HIGH INPUT - R6, R7
; LOW INPUT - R4, R5
; answer resides in R2, and R3.

SUBB16_16:
;Step 1 of the process
MOV A,R7 ;Move the low-byte into the accumulator
CLR C ;Always clear carry before first subtraction
SUBB A,R5 ;Subtract the second low-byte from the accumulator
MOV R3,A ;Move the answer to the low-byte of the result

;Step 2 of the process
MOV A,R6 ;Move the high-byte into the accumulator
SUBB A,R4 ;Subtract the second high-byte from the accumulator
MOV R2,A ;Move the answer to the low-byte of the result

RET


Char: DB 135,133,135,128,128,128,128,128,0
Degrees: DB ' Degrees',0
CopyLeft0: DB 'Final Yr Project',0
CopyLeft1: DB ' Accelerometer ',0
NoSignal0: DB 'Detect No Signal',0

END