MEGA8做的简易频率计 - 圣龙扬特-AVR电子

'---------------------------------------------------------------------------------------
'Name                   : Cymometer.bas
'Copyright             : 圣龙扬特-AVR电子
'Micro                   : AtMega8
'Author                : slyt
'---------------------------------------------------------------------------------------
$regfile = "M8def.dat"                                     ' specify the used micro
$crystal = 8000000                                        ' used crystal frequency
$hwstack = 32                                              ' default use 32 for the hardware stack
$swstack = 20                                              ' default use 10 for the SW stack
$framesize = 40                                           ' default use 40 for the frame space

$lib "single.lbx"

'To use it as a COUNTER, you can choose on which edge it is trigereed
Config Timer1 = Counter , Edge = Falling
On Timer1 Tim1_isr

'Valid values are 1-0.125us , 8-1us, 64-8us, 256-32us or 1024-128us
Config Timer0 = Timer , Prescale = 64
On Timer0 Tim0_isr

Config Lcdpin = Pin , Db4 = Portd.2 , Db5 = Portd.1 , Db6 = Portd.3 , Db7 = Portd.4 , E = Portc.4 , Rs = Portc.5
Config Lcd = 20 * 2
Cursor Off Noblink

Ddrc.1 = 1
Led Alias Portc.1

Dim Wf As Long                                           '频率变量,并记录COUNTER1中断次数
Dim Tim0_counter As Word                                  'Timer0中断次数
Dim Tim0_counter_times As Word                            'timer0中断次数倍数
Dim Tim1_counter As Byte                                  'Timer1中断次数
Dim Mybyte As Byte
Dim Ss As Single
Dim Lcdstr As String * 7

'Deflcdchar 0 , 32 , 9 , 9 , 9 , 14 , 8 , 16 , 32          ' replace ? with number (0-7)

Led = 1

Cls
Locate 1 , 8
Lcd "F: 000.00 KHz"
Locate 2 , 8
Lcd "T: 000.00  mS"

Tim0_counter_times = 250                                  '初始250倍,250X2=500ms,即第一次采样500ms后计算
Tim0_counter = 0
Counter1 = 0
Timer0 = 5
Wf = 0

Enable Interrupts
Enable Timer0
Start Counter1

Do
Idle

If Tim0_counter = Tim0_counter_times Then
   Disable Timer0
   Stop Counter1
   Wf = Wf * 65536
   Wf = Wf + Counter1                                  '总脉冲次数
   'Tim0_counter * 2/1000  '总计时毫秒数。除1000转换成秒
   Wf = Wf * 500                                        '频率=脉冲次数/总时间
   Wf = Wf / Tim0_counter                               '计算出Hz数

   Locate 1 , 18
   Select Case Wf
      Case Is > 999999                                  '显示MHz
         Lcd "MHz"
         Ss = Wf / 1000000
      Case Is > 999                                     '显示KHZ
         Lcd "KHz"
         Ss = Wf / 1000
      Case Else                                        '显示Hz
         Lcd " Hz"
         Ss = Wf
   End Select

   Lcdstr = Fusing(ss , "#.##")
   Mybyte = 7 - Len(lcdstr)
   Lcdstr = Space(mybyte) + Lcdstr                      '补齐6个字符

   Locate 1 , 10
   Lcd Lcdstr                                           '显示Hz数

   Locate 2 , 19
   Select Case Wf
      Case Is > 1000                                  '显示uS
         Lcd Chr(&He4) ; "S"
         Ss = 1000000 / Wf
      Case 0                                           '显示mS
         Lcd "mS"
         Ss = 0
      Case Else                                        '显示ms
         Lcd "mS"
         Ss = 1000 / Wf
   End Select

   Lcdstr = Fusing(ss , "#.##")
   Mybyte = 7 - Len(lcdstr)
   Lcdstr = Space(mybyte) + Lcdstr                      '补齐6个字符

   Locate 2 , 10
   Lcd Lcdstr                                           '显示周期数

   Locate 1 , 8
   Lcd "F:"
   Locate 2 , 8
   Lcd "T:"

   If Wf > 10000 Then                                  '如果频率大于10K,采样周期改为200ms
      Tim0_counter_times = 100
      Else
      If Wf > 500 Then
         Tim0_counter_times = 250                      '如果频率大于500Hz,采样周期改为500ms
         Else
         Tim0_counter_times = 500                      '采样周期为1S
      End If
   End If

   Wf = 0                                              '重置初始值
   Tim0_counter = 0
   Timer0 = 5
   Counter1 = 0
   Enable Timer0
   Start Counter1

End If

Loop

End

'============计时2ms===============
'Timer0=5, 250*8=2000us=2ms
Tim0_isr:
Incr Tim0_counter
Timer0 = 5
Return

'=======计数器溢出次数=============
Tim1_isr:
Incr Wf
Return