'     ATTiny 2313   '
' Frequency Counter '
'

$regfile = "ATtiny2313.dat"
$crystal = 20000000                                         '20MHz clock
Config Pind.4 = Output                                      'LED Pin


'Config LCD
Config Lcdpin = Pin , Db4 = Portb.2 , Db5 = Portb.1 , Db6 = Portb.0 , Db7 = Portd.6 , E = Portb.3 , Rs = Portb.4
Config Lcd = 16 * 2
Config Lcdbus = 4
Config Lcdmode = Port


'Config Timers
Config Timer0 = Timer , Prescale = 1024                     'Loop Timer
Config Timer1 = Counter , Edge = Rising                     'Frequency Counter


'Config Variables
Dim Temp As Long
Dim Ovf0 As Long
Dim Ovf1 As Long
Dim Freq As Long
Dim Freq1 As String * 7
Dim Freq2 As String * 3
Dim Freq3 As String * 4
Dim Position As Byte


'Config Interrupts
Enable Interrupts
Enable Timer0                                               'Timer interrupt
On Timer0 Incr_ovf0                                         'Overflow Routine
Enable Timer1                                               'Counter interrrupt
On Timer1 Incr_ovfl                                         'Overflow routine


'Main
Cls
Upperline                                                   'Clear LCD Display
Lcd " nuxieshop.com"
Lowerline
Lcd "   Fun Count"
Cursor Off
Wait 2

'Loop
Do
   Portd.4 = 0                                              'LED On
   Timer0 = 0                                               'Reset counts
   Counter1 = 0
   Ovf0 = 0                                                 'Reset overflows
   Ovf1 = 0

   While Ovf0 <= 75                                         'One second loop @ 20 MHz
   nop
   Wend
   Waitus 3900
   Portd.4 = 1                                              'LED Off
   Disable Timer0                                           'Stop Timers
   Disable Timer1

   Temp = Ovf1 * 65536                                      'Calc frequency
   Freq = Temp + Counter1
   Cls                                                      'Clear display
   Locate 1 , 1
   Freq1 = Str(freq)

   Select Case Freq                                         'Choose Frequency Range
   Case Is >= 1000000 : Goto Mhz
   Case Is >= 100000 : Goto Khzxxx
   Case Is >= 10000 : Goto Khzxx
   Case Is > 1000 : Goto Khzx
   End Select

'1-999 Hz
   Position = 7 - Len(freq1)
   Locate 1 , Position
   Lcd Freq ; " Hz"
   Goto Outputdisplay

Mhz:
   Freq2 = Left(freq1 , 1)
   Freq3 = Mid(freq1 , 2 , 4)
   Lcd Freq2 ; "." ; Freq3 ; " MHz"
   Goto Outputdisplay
Khzxxx:
   Freq2 = Left(freq1 , 3)
   Freq3 = Mid(freq1 , 4 , 2)
   Lcd Freq2 ; "." ; Freq3 ; " KHz"
   Goto Outputdisplay
Khzxx:
   Freq2 = Left(freq1 , 2 )
   Freq3 = Mid(freq1 , 3 , 3)
   Lcd Freq2 ; "." ; Freq3 ; " KHz"
   Goto Outputdisplay
Khzx:
   Freq2 = Left(freq1 , 1 )
   Freq3 = Mid(freq1 , 2 , 4)
   Lcd " " ; Freq2 ; "." ; Freq3 ; " KHz"
   Goto Outputdisplay

Outputdisplay:
Locate 2 , 1                                                'Setup LCD cursor


   Cursor Off
                                                         'Restart timers
   Enable Timer0
   Enable Timer1
Loop

'Interrupt routines
'*****************************************
Incr_ovfl:
   Incr Ovf1
   Return

'*****************************************
Incr_ovf0:
   Incr Ovf0
   Return

End