'**********************************************************************************
'                    READING OUT THE LDU VIA FOUR PCF 8591
'**********************************************************************************
'
'     SCL  (To Atmega 8 / Portd.4 + 10K pullup to +5V)
'     SDA  (To Atmega 8 / Portd.5 + 10K pullup to +5V)
'
'     Beeper: Portb.0
'
'     Paste code, generated by blacklevel and whitelevel program into this program
'
'**********************************************************************************


$regfile = "m8def.dat"                                      'Atmega8-declarations
$crystal = 3686400
$baud = 38400

Ddrb = &B00000001

Config Sda = Portd.5
Config Scl = Portd.4
Config I2cdelay = 10

Const Contrast = 35                                         'adjust contrast between surface and line (ca.20...50 20=no contrast 50=high contrast -- this contrastlevel is needed to find out, whether there's a line or not -- if there's no line, an alert will occur)

Dim I As Byte                                               'i...k = general purpose variables
Dim J As Byte
Dim K As Byte
Dim L As Byte

Dim Ldr(16) As Integer                                      'ldr contains the value of the light dependant resistors
Dim Maxbrightval As Byte                                    'maxbright=value of brightest ldr
Dim Maxbrightsen As Byte                                    'maxbrightsensor=number of brightest ldr
Dim Difbright As Word                                       'difference between the brightest sensor and the average brightnes of the other sensors
Dim Ool As Byte                                             'outofline alert

Do


'**********************************************************************************
' linedetection
' read the values of the 16 sensors via i²c
'**********************************************************************************

    I2cstart                                                'i2c start condition
    I2cwbyte &B10010000                                     'send pcf address (write)
    I2cwbyte &B01000101                                     'send control byte (auto-increment on, internal oscillator on)
    I2cstart                                                'repeated start condition
    I2cwbyte &B10010001                                     'send pcf addressieren (read)
    I2crbyte Ldr(1) , Ack                                   'read value of adc0 & acknowledge
    I2crbyte Ldr(2) , Ack                                   '...
    I2crbyte Ldr(3) , Ack                                   '...
    I2crbyte Ldr(4) , Ack                                   'read value of adc3 / don't acknowledge
    I2crbyte Ldr(1) , Ack                                   'read value of adc0 & acknowledge
    I2crbyte Ldr(2) , Ack                                   '...
    I2crbyte Ldr(3) , Ack                                   '...
    I2crbyte Ldr(4) , Nack                                  'read value of adc3 / don't acknowledge
    I2cstop

    I2cstart                                                'i2c start condition
    I2cwbyte &B10010010                                     'send pcf address (write)
    I2cwbyte &B01000101                                     'send control byte (auto-increment on, internal oscillator on)
    I2cstart                                                'repeated start condition
    I2cwbyte &B10010011                                     'send pcf addressieren (read)
    I2crbyte Ldr(5) , Ack                                   'read value of adc0 & acknowledge
    I2crbyte Ldr(6) , Ack                                   '...
    I2crbyte Ldr(7) , Ack                                   '...
    I2crbyte Ldr(8) , Ack                                   'read value of adc3 / don't acknowledge
    I2crbyte Ldr(5) , Ack                                   'read value of adc0 & acknowledge
    I2crbyte Ldr(6) , Ack                                   '...
    I2crbyte Ldr(7) , Ack                                   '...
    I2crbyte Ldr(8) , Nack                                  'read value of adc3 / don't acknowledge
    I2cstop

    I2cstart                                                'i2c start condition
    I2cwbyte &B10010100                                     'send pcf address (write)
    I2cwbyte &B01000101                                     'send control byte (auto-increment on, internal oscillator on)
    I2cstart                                                'repeated start condition
    I2cwbyte &B10010101                                     'send pcf addressieren (read)
    I2crbyte Ldr(9) , Ack                                   'read value of adc0 & acknowledge
    I2crbyte Ldr(10) , Ack                                  '...
    I2crbyte Ldr(11) , Ack                                  '...
    I2crbyte Ldr(12) , Ack                                  'read value of adc3 / don't acknowledge
    I2crbyte Ldr(9) , Ack                                   'read value of adc0 & acknowledge
    I2crbyte Ldr(10) , Ack                                  '...
    I2crbyte Ldr(11) , Ack                                  '...
    I2crbyte Ldr(12) , Nack                                 'read value of adc3 / don't acknowledge
    I2cstop

    I2cstart                                                'i2c start condition
    I2cwbyte &B10010110                                     'send pcf address (write)
    I2cwbyte &B01000101                                     'send control byte (auto-increment on, internal oscillator on)
    I2cstart                                                'repeated start condition
    I2cwbyte &B10010111                                     'send pcf addressieren (read)
    I2crbyte Ldr(13) , Ack                                  'read value of adc0 & acknowledge
    I2crbyte Ldr(14) , Ack                                  '...
    I2crbyte Ldr(15) , Ack                                  '...
    I2crbyte Ldr(16) , Ack                                  'read value of adc3 / don't acknowledge
    I2crbyte Ldr(13) , Ack                                  'read value of adc0 & acknowledge
    I2crbyte Ldr(14) , Ack                                  '...
    I2crbyte Ldr(15) , Ack                                  '...
    I2crbyte Ldr(16) , Nack                                 'read value of adc3 / don't acknowledge
    I2cstop                                                 'i2c stop condition


' paste code from LDU_adjust_black here:

Ldr(1) = Ldr(1) - 38
Ldr(2) = Ldr(2) - 37
Ldr(3) = Ldr(3) - 37
Ldr(4) = Ldr(4) - 43

Ldr(5) = Ldr(5) - 40
Ldr(6) = Ldr(6) - 40
Ldr(7) = Ldr(7) - 48
Ldr(8) = Ldr(8) - 36

Ldr(9) = Ldr(9) - 42
Ldr(10) = Ldr(10) - 40
Ldr(11) = Ldr(11) - 39
Ldr(12) = Ldr(12) - 41

Ldr(13) = Ldr(13) - 33
Ldr(14) = Ldr(14) - 33
Ldr(15) = Ldr(15) - 28
Ldr(16) = Ldr(16) - 22

' end code from LDU_adjust_black

For I = 1 To 16
Ldr(i) = Ldr(i) * 200
Next I

' paste code from LDU_adjust_white here:

Ldr(1) = Ldr(1) / 139
Ldr(2) = Ldr(2) / 139
Ldr(3) = Ldr(3) / 142
Ldr(4) = Ldr(4) / 138

Ldr(5) = Ldr(5) / 138
Ldr(6) = Ldr(6) / 142
Ldr(7) = Ldr(7) / 140
Ldr(8) = Ldr(8) / 142

Ldr(9) = Ldr(9) / 142
Ldr(10) = Ldr(10) / 139
Ldr(11) = Ldr(11) / 141
Ldr(12) = Ldr(12) / 138

Ldr(13) = Ldr(13) / 149
Ldr(14) = Ldr(14) / 148
Ldr(15) = Ldr(15) / 150
Ldr(16) = Ldr(16) / 142


' end code from LDU_adjust_white

' invert values (black line)

For I = 1 To 16
Ldr(i) = 200 - Ldr(i)
Next I

' print out bargraph

Waitms 100

Print Chr(12)
For I = 1 To 16                                             'clear screen

If I > 9 Then
Print I ; " = " ; Ldr(i);
Else
Print I ; "  = " ; Ldr(i);
End If

If Ldr(i) < 10 Then Print "  ";
If Ldr(i) > 9 And Ldr(i) < 100 Then Print " ";
Print " ";

K = Ldr(i) / 4
For L = 1 To K
Print "-";
Next L

Print ""


J = I Mod 4
If J = 0 Then Print ""

Next I

Loop

End