'The ATmega8 is used.
$regfile = "m8def.dat"
$crystal = 4000000
Config Sda = Portc.4
Config Scl = Portc.5
Config I2cdelay = 10
Config Lcd = 16 * 2
Config Lcdpin = Pin , Db4 = Portb.0 , Db5 = Portb.1 , Db6 = Portb.2 , Db7 = Portb.3 , E = Portb.4 , Rs = Portb.5
Config Pind.7 = Output

Led Alias Portd.7

'Jcl1562b write and read i2c address
Const Jcl1562bwrite = &H70
Const Jcl1562bread = &H71
'Lt6904 write i2c address
Const Lt6904write = &H2E
'Lt6904 clk/clk-not configuration
'clk=on, clk-not=off
Const Lt6904config = &B10

Dim Frequency As Single
Dim Freqincrement As Single
Dim Tmp As Single
Dim Pwr As Single
Dim Oct As Byte
Dim Dac As Word
Dim Dactmp As Word
Dim Lt6904byte1 As Byte
Dim Lt6904byte2 As Byte
Dim Lttmp As Byte
Dim Hexstr As String * 4

Pwr = 2.0
Frequency = 1000000.0
Freqincrement = 100000.0
Cls

Do
 Set Led
 Waitms 50
 Reset Led
 Waitms 50
 'I2cstart
 'I2cwbyte Jcl1562bwrite
 'I2cwbyte 255
 'I2cstop
 'Waitms 250
 'I2cstart
 'I2cwbyte Jcl1562bwrite
 'I2cwbyte 0
 'I2cstop
 'Waitms 250
 'calculate oct and dac for this frequency, see
 'lt6904 datasheet
 Tmp = Frequency / 1039
 Tmp = Log10(tmp)
 Tmp = 3.322 * Tmp
 Oct = Int(tmp)
 Tmp = Oct + 10
 Tmp = Power(pwr , Tmp)
 Tmp = Tmp / Frequency
 Tmp = Tmp * 2078
 Dac = Int(tmp)
 Dac = 2048 - Dac
 Upperline
 Lcd "Frequency (kHz) " ; Frequency ; "    "
 'calculate lt6904 two frequency and configuration setting bytes
 'Lcd Oct ; " " ; Dac ; " "
 'first lt6904 byte is oct shifted left four bits
 Lt6904byte1 = Oct
 Shift Lt6904byte1 , Left , 4
 'plus the lower two bits of the high byte of dac shifted 2 bits to the left
 Lttmp = High(dac)
 Lttmp = Lttmp And &B00000011
 Shift Lttmp , Left , 2
 Lt6904byte1 = Lt6904byte1 + Lttmp
 'plus the upper two bits of the low byte of dac shifted 6 bits to the right
 Lttmp = Low(dac)
 Lttmp = Lttmp And &B11000000
 Shift Lttmp , Right , 6
 Lt6904byte1 = Lt6904byte1 + Lttmp
 'second lt6904 byte is the left six bits of the low byte of dac
 'plus the lt6904 config bits
 Lt6904byte2 = Low(dac)
 Shift Lt6904byte2 , Left , 2
 Lt6904byte2 = Lt6904byte2 + Lt6904config
 Hexstr = Hex(lt6904byte1)
 Lowerline
 Lcd "Fbyte1: " ; Hexstr ; " "
 Hexstr = Hex(lt6904byte2)
 Lcd "Fbyte2: " ; Hexstr ; " "
 I2cstart
 I2cwbyte Lt6904write
 Lcd "I2C-status: " ; Err ; " "
 'Waitms 50
 I2cwbyte Lt6904byte1
 Lcd Err ; " "
 'Waitms 50
 I2cwbyte Lt6904byte2
 Lcd Err ; " "
 'Waitms 50
 I2cstop
 If Frequency > 1000000.0 Then Freqincrement = -10000.0
 If Frequency < 500000.0 Then Freqincrement = 10000.0
 Frequency = Frequency + Freqincrement
Loop

End