'Voltage Controled DDS(AD9850) for ICB-700mod. v1.04
'2014.08.09  by JA1VZV
'Freq.range 28.1745-28.4300  MHz
'Call ch=28.305MHz
'RX DDS output = F-455kHz
'0.5kHz step mode (Usage:Lump ON + power on)
'================Pin Assignment=========================
'DDS FqUD out:B3 / D7 out:B4 / Wclk out:B5
'Tune in:C0 / CH1 in:B0 / PTT in:C2 / Step select in: B2
'Auto-shift:C1
'=======================================================
'Use external ceramic resonator 560kHz

$regfile = "m88def.dat"
$crystal = 560000                                     'Spec. Sclock freq.

'--- config port ---
Config Portb = &B00111000                             'B0-2,6-7:In ,B3-5:Out
Config Portc = &B0000010                              'C0,2-6input ,C1:Output
Config Portd = &H00                                   'All input(Not used)

'--- port pullup ---
Portb = &B00000101                                    'B0:L=CH1,B2:L=0.5kHz
Portc = &B1000100                                     'C0:Tune,C1:Shift,C2:L=TX,C6:L:Reset
Portd = &H00                                          'All low

'--- debounce set ---
Config Debounce = 1

'ADC mode setting & start
Config Adc = Single , Prescaler = Auto
Start Adc

'---Define Variables---
Dim R As Word                                         'Tune VR value
Dim R1 As Integer                                     'Tune VR past value
Dim R2 As Long                                        'Tune calc
Dim Rd As Integer                                     'Tune calc
Dim I As Long                                         'IF freqency
Dim F0 As Long                                        'Lower Freq. data
Dim F As Long                                         'Freq. data
Dim Ff As Single                                      'For F calc(DDS)
Dim Fa As Long                                        'For F calc(DDS)
Dim Fb As Long                                        'For F calc(DDS)
Dim Lk As Bit                                         'Freq.Lock flag
Dim Md As Bit                                         'Dial mode flag
Dim Dc As Byte                                        'DDS command
Dim Dd As Byte                                        '
Dim Tr As Bit                                         'Tx flag TX=1

'---Variables initialize---
I = 455000                                            'IF freq.[Hz]
Lk = 0                                                'Lock bit to unlock
F0 = 28174500                                         'Lower limit Freq.
R1 = 1026                                             'Initial ADC memory value
Md = Pinb.2                                           'Dial mode read & memory
 If Md = 1 then
   Dd=2
  Else
   Dd=1
 End If
Dc = &B00000000                                       'DDS command value
Tr = 0                                                'Tx flag reset (=Rx)

'---Set DDS to serial mode---
 Reset Portb.4
 Reset Portb.5
  Waitus 10
 Set Portb.5
  Waitus 10
 Reset Portb.5
  Waitus 10
 Set Portb.3
  Waitus 10
 Reset Portb.3
  Waitus 10

'*** Main loop ***
Do
  If Pinb.0 = 1 Then                                  'If Vfo mode then
      R = Getadc(0)                                   ' Read ADC0 (TUNE in)
    Else                                              'else
      R = 522                                         ' Set fixed value(=28.305MHz)
  End If

     Rd = R - R1                                      'Calc.VR data cange
     Rd = Abs(rd)
    If Lk = 0 Then                                    'Not F-lock then
     If Rd > 1 Then                                   'If VR value canged
      R1 = R
     If Md = 0 Then                                   '0.5kHz mode
         Shift R , Right , 1                          ' /2
         R2 = R * 500
       Else                                           '10kHz mode
         R = R \ 40
         R2 = R * 10000
         R2 = R2 + 500                                'Add offset freq.
     End If
      F = F0 + R2                                     'Calc. Operation freq

     If F >= 28275000 And F <= 28295000 Then          'MPU clock auto-shift
       Reset Portc.1
      Else
       Set Portc.1

     End If
      Gosub Dds                                       'Set freq.to DDS
     End If
    End If
  If Lk = 1 And Rd >= 12 Then Lk = 0                  'F-lock off(F changed >3kHz)

 ' Check PTT
  If Tr = 1 Then                                      'In TX
    Debounce Pinc.2 , 1 , Rx , Sub                    ' Check PTT Off
   Else                                               'In RX
    Debounce Pinc.2 , 0 , Tx , Sub                    ' Check PTT On
  End If

 Waitms 50
Loop
'= End main loop =


'*** DDS data calc & set***
Dds:
 '---Freq.calc---
 If Tr = 1 Then                                       'IF in TX then
    Fa = F                                            'Set TX Freq.
  Else                                                'In RX
    Fa = F - I                                        'Set RXLo Freq.
 End If

  Ff = Fa * 34.36010179                               'Conv. F to DDS data
  Fb = Ff                                             'Conv. to integer
 '---Set DDS data---
 Shiftout Portb.4 , Portb.5 , Fb , 3 , 32 , 0
 Shiftout Portb.4 , Portb.5 , Dc , 3 , 8 , 0
  Waitus 10
 Set Portb.3
  Waitus 10
 Reset Portb.3
Return

'*** TX sub ***
Tx:
  Tr = 1                                              'TX flag on
  Lk = 1                                              'F-Lock flag on
  Gosub Dds
Return

'*** RX sub ***
Rx:
  Tr = 0                                              'TX flag off
  Gosub Dds
Return