'******************************************
'  BME280 Beispiel Code
'  (c) 2015 by Michael Lehmann
'   Siehe http://www.mikrocontroller.net/topic/384287?goto=new#new
'
'*******************************************************************
'*    Eigene Version für LCD und Runnerplatine /183600@gmail.com   *
'*    V2.1    ohne Änderungen                                      *
'*    V2.2    Anpassung an LCD, Atmega32A,                         *
'*            (Hum wir immer mit 0.0% angezeigt)                   *
'*    V2.3    Serielle Ausgaben entfernt                           *
'*    V2.4    Preasure_64bit entfernt                              *
'*    V2.5    Höhenkorrektur für Home eingefügt                    *
'*    V2.6    Automatische Druckkorrektur "auf Meereshöhe"         *
'*    V2.7    Automatische Druckkorrektur mit Bisektionsverfahren  *
'*******************************************************************

$regfile = "m32Adef.dat"
$crystal = 16000000
$hwstack = 50
$swstack = 50
$framesize = 100

'I2C config
Config Sda = Porta.2
Config Scl = Porta.1

'---------------- LCD - Displayausgabe konfigurieren -------------------------
Config Lcdpin = Pin , Db4 = Portb.0 , Db5 = Portb.1 , Db6 = Portb.2 , Db7 = Portb.3 , E = Portb.5 , Rs = Portb.4
Config Lcd = 24x2 : Config Lcdbus = 4

Cls : Lcd "BME280 V2.6"
Waitms 100


'******************************************
' Einstellungen für den BME280 Sensor

Const Bme280_adress = &HEC                        'Sensoradresse

'Oversampling
Const Osrs_t = &B101
Const Osrs_p = &B101
Const Osrs_h = &B101

'Mode Register
Const Mode_reg = &B11                             'Normal Mode

't_sb
Const T_sb = &B000                                't_sb = 0.5ms

'IIR Filter
Const Filter = &B100                              'Filter = 16

'Allgemeine Variablen, für die Grundfunktionen des Sensors nicht notwendig
Dim Txt As String * 16
Dim Alt As Long

Dim Wert_array(24) As Byte                        'Datenarray für die i2c komunikation

'Kalibrierwerte vom Sensor
Dim Dig_t1 As Word
Dim Dig_t2 As Integer
Dim Dig_t3 As Integer
Dim Dig_p1 As Word
Dim Dig_p2 As Integer
Dim Dig_p3 As Integer
Dim Dig_p4 As Integer
Dim Dig_p5 As Integer
Dim Dig_p6 As Integer
Dim Dig_p7 As Integer
Dim Dig_p8 As Integer
Dim Dig_p9 As Integer
Dim Dig_h1 As Byte
Dim Dig_h2 As Integer
Dim Dig_h3 As Byte
Dim Dig_h4 As Integer
Dim Dig_h5 As Integer
Dim Dig_h6 As Byte

'unkompensierte Sensor Werte
Dim Ut As Long
Dim Up As Long
Dim Uh As Long

'Funktionsübergreifende Hilfsvariablen
Dim T_fine As Long
Dim P_old As Dword

'kompensierte Sensor Werte
Dim T As Long
Dim P_32 As Dword
Dim H As Dword

'Automatische Druckkorrektur auf Meereshöhe
Dim Dp As Dword , Delta_p As Dword , Alt_0 As Long , Delta_alt As Long

'SUBs und FUNCTONs declarieren
Declare Sub I2c_write(byval Device_adres As Byte , Byval Reg_adres As Byte , Byval Wert As Byte)
Declare Sub I2c_read(byval Device_adres As Byte , Byval Reg_adres As Byte , Byval Wert_count As Byte )
Declare Sub Setup_bme280()
Declare Sub Read_bme280_value()
Declare Function Temp() As Long
Declare Function Pressure_32() As Dword
Declare Function Humidity() As Dword

'sonstige Funktionen
Declare Function Absolute_altitude(byval Pressure As Dword) As Long

'Initialisierung des BME280 Sensor
Call Setup_bme280()                               'Kalibrierwerte vom Sensor lesen, Filterwerte schreiben

'*** Hauptprogramm


' Berechnung einer Höhenkorrektur für die Druckanzeige, iterativ
' Angezeigt wird der auf Meeresniveau erhöhte Druck


Dp = 101325                                       'Normaldruck auf Meereshöhe in Pascal
Delta_p = 16384 / 4                               '=2^14 ergibt 14 Schritte
Alt_0 = 42000                                     'Höhe der Messstation in cm (Einheit wegen Sensorauflösung)

'Reduzierung des Druckes um je 100Pa(=mBar), bis Alt_0 überschritten wird
Do
   Alt = Absolute_altitude(dp)

   If Alt > Alt_0 Then
      Dp = Dp + Delta_p
   Else
      Dp = Dp - Delta_p
   End If
   Delta_p = Delta_p / 2

   Delta_alt = Alt - Alt_0
   Delta_alt = Abs(delta_alt)

   Locate 2 , 1
   Lcd " DP=" ; Dp ; "   " ; Alt ; "    " ; Alt_0 ; "  " ; Delta_alt ; "    "
   Waitms 500

Loop Until Delta_p = 0 Or Delta_alt <= 10         'Abweichung <=10cm

Dp = 101325 - Dp

Cls
Lcd "Korrekturwert:" ; Dp ;
Wait 1

Do

   '** BME280 auslesen
   Call Read_bme280_value()
   'List die unkompensierten Wert vom Sensor,
   'diese werden in Ut, Up, Uh abgelegt

   '** Temperatur
   T = Temp()
   'Gibt die Temperatur in °C zurück, die Auflösung beträgt 0.01°C
   'Der Wert 2415 entspricht 24.15°C

   '** Luftdruck mit 32bit Berechnung
   P_32 = Pressure_32()
   'Gibt den Luftdruck in hPa zurück, die Auflösung beträgt 0.01hPa
   'Der Wert 96386 entspricht 963.86hPa

   P_32 = P_32 + Dp

   '** Luftfeuchte
   H = Humidity()
   'Gibt die Luftfeuchtigkeit in % zurück, die Auflösung beträgt 0.001hPa
   'Der Wert 46333 entspricht 46.333%
   H = H / 100

   '** Höhe über Meer
   Alt = Absolute_altitude(p_32)
   'Gibt die Höhe über Meer in meter zurück, die Auflösung beträgt bei 64bit Luftdruckberechnung 0.01m
   'Der Wert 52078 entspricht 520.78m
   'Für die Berechnung mit 32bit Luftdruck müssen in der Function ABSOLUTE_ALTITUDE die beiden Faktoren umkomentiert werden.
   Alt = Alt_0


   '** Messwerte ausgeben

   '   Lcd "Ut:" ; Ut ; " Up:" ; Up ; " Uh:" ; Uh
   ' Wait 1
   Wait 1 : Cls

   Txt = Str(t)
   Txt = Format(txt , "00.00")
   Locate 1 , 1
   Lcd "T:" ; Txt

   Txt = Str(p_32)
   Txt = Format(txt , "00.00")
   Locate 1 , 9
   Lcd "P32:" ; Txt

   Txt = Str(h)
   Txt = Format(txt , "00.0")
   Locate 2 , 1
   Lcd "Hum:" ; Txt ; "%"

   Txt = Str(alt)
   Txt = Format(txt , "00.00")
   Locate 2 , 9
   Lcd "Alt:" ; Txt ; "m"

Loop

End



Sub I2c_write(device_adres As Byte , Reg_adres As Byte , Wert As Byte)
   I2cstart
   I2cwbyte Device_adres
   I2cwbyte Reg_adres
   I2cwbyte Wert
   I2cstop
   Waitms 10
End Sub


Sub I2c_read(device_adres As Byte , Reg_adres As Byte , Wert_count As Byte )
   Local X As Byte
   Local Y As Byte
   Y = Wert_count - 1

   I2cstart                                       'Start I2C
   I2cwbyte Device_adres                          'Sende Slave Adresse
   I2cwbyte Reg_adres                             'Register Adresse
   I2cstart
   Incr Device_adres
   I2cwbyte Device_adres                          'sende Slave Adresse +1 für Lesen
   If Wert_count > 1 Then
      For X = 1 To Y
         I2crbyte Wert_array(x) , Ack             'lese Wert
      Next
   End If
   I2crbyte Wert_array(wert_count) , Nack         'lese Wert
   I2cstop
   Waitms 10
End Sub


Sub Read_bme280_value()
   Call I2c_read(bme280_adress , &HF7 , 8 )

   'unkompensierter Druckwert
   Up = Wert_array(1)
   Shift Up , Left , 8
   Up = Up + Wert_array(2)
   Shift Up , Left , 8
   Up = Up + Wert_array(3)
   Shift Up , Right , 4

   'unkompensierter Temperaturwert
   Ut = Wert_array(4)
   Shift Ut , Left , 8
   Ut = Ut + Wert_array(5)
   Shift Ut , Left , 8
   Ut = Ut + Wert_array(6)
   Shift Ut , Right , 4

   'unkompensierter Feuchtewert
   Uh = Wert_array(7)
   Shift Uh , Left , 8
   Uh = Uh + Wert_array(8)
End Sub


Function Temp() As Long
   Local Var1 As Long
   Local Var2 As Long
   Local X As Long

   Var1 = Ut
   Shift Var1 , Right , 3 , Signed
   X = Dig_t1
   Shift X , Left , 1 , Signed
   Var1 = Var1 - X
   Var1 = Var1 * Dig_t2
   Shift Var1 , Right , 11 , Signed

   Var2 = Ut
   Shift Var2 , Right , 4 , Signed
   Var2 = Var2 - Dig_t1
   Var2 = Var2 * Var2
   Shift Var2 , Right , 12 , Signed
   Var2 = Var2 * Dig_t3
   Shift Var2 , Right , 14 , Signed

   T_fine = Var1 + Var2
   Temp = T_fine * 5
   Temp = Temp + 128
   Shift Temp , Right , 8 , Signed
End Function


Function Pressure_32() As Dword
   Local Var1 As Long
   Local Var2 As Long
   Local X As Long
   Local Y As Long
   Local Z As Dword

   Var1 = T_fine
   Shift Var1 , Right , 1 , Signed
   Var1 = Var1 - 64000

   X = Var1
   Shift X , Right , 2
   Var2 = X * X
   Shift Var2 , Right , 11 , Signed
   Var2 = Var2 * Dig_p6

   X = Var1 * Dig_p5
   Shift X , Left , 1 , Signed
   Var2 = Var2 + X

   X = Var2
   Shift X , Right , 2 , Signed
   Y = Dig_p4
   Shift Y , Left , 16 , Signed
   Var2 = X + Y

   X = Var1
   Shift X , Right , 2 , Signed
   X = X * X
   Shift X , Right , 13 , Signed
   X = X * Dig_p3
   Shift X , Right , 3 , Signed
   Y = Dig_p2 * Var1
   Shift Y , Right , 1 , Signed
   Var1 = X + Y
   Shift Var1 , Right , 18 , Signed

   Var1 = 32756 + Var1
   Var1 = Var1 * Dig_p1
   Shift Var1 , Right , 15 , Signed

   If Var1 = 0 Then
      Pressure_32 = P_old
      Exit Function
   End If

   X = 1048576 - Up
   Y = Var2
   Shift Y , Right , 12 , Signed
   X = X - Y
   Pressure_32 = X * 3125

   If Pressure_32 < &H80000000 Then
      Shift Pressure_32 , Left , 1 , Signed
      Pressure_32 = Pressure_32 / Var1
   Else
      Pressure_32 = Pressure_32 / Var1
      Pressure_32 = Pressure_32 * 2
   End If

   Z = Pressure_32
   Shift Z , Right , 3 , Signed
   Z = Z * Z
   Shift Z , Right , 13 , Signed
   Z = Z * Dig_p9
   Shift Z , Right , 12 , Signed
   Var1 = Z

   Z = Pressure_32
   Shift Z , Right , 2 , Signed
   Z = Z * Dig_p8
   Shift Z , Right , 13 , Signed
   Var2 = Z

   Z = Var1 + Var2
   Z = Z + Dig_p7
   Shift Z , Right , 4 , Signed
   Pressure_32 = Pressure_32 + Z
   P_old = Pressure_32
End Function


Function Humidity() As Dword
   Local Var1 As Long
   Local X As Long
   Local Y As Long
   Local Z As Long

   Var1 = T_fine - 76800

   X = Uh
   Shift X , Left , 14 , Signed
   Y = Dig_h4
   Shift Y , Left , 20 , Signed
   X = X - Y
   Y = Dig_h5 * Var1
   X = X - Y
   X = X + 16384
   Shift X , Right , 15 , Signed

   Y = Var1 * Dig_h6
   Shift Y , Right , 10 , Signed

   Z = Var1 * Dig_h3
   Shift Z , Right , 11 , Signed
   Z = Z + 32768

   Y = Y * Z
   Shift Y , Right , 10 , Signed
   Y = Y + 2097152
   Y = Y * Dig_h2
   Y = Y + 8192
   Shift Y , Right , 14 , Signed

   Var1 = X * Y

   X = Var1
   Shift X , Right , 15 , Signed
   X = X * X
   Shift X , Right , 7 , Signed
   X = X * Dig_h1
   Shift X , Right , 4 , Signed
   Var1 = Var1 - X

   If Var1 < 0 Then
      Var1 = 0
   End If

   If Var1 > 419430400 Then
      Var1 = 419430400
   End If

   Shift Var1 , Right , 12 , Signed
   Humidity = Var1 / 1.024
End Function



Sub Setup_bme280()
   Local X As Byte

   'Warten bis der Sensor die Startup Prozedur abgeschlossen hat
   Waitms 5

   'BME280 schreibe Filter Wert und t_sb Einstellung
   X = T_sb
   Shift X , Left , 3
   X = X + Filter
   Shift X , Left , 2
   Call I2c_write(bme280_adress , &HF5 , X)

   'BME280 schreibe OSRS_h Wert (ctrl_hum register)
   Call I2c_write(bme280_adress , &HF2 , Osrs_h)

   'BME280 schreibe OSRS_t, OSRS_p, Mode Wert (ctrl_meas register)
   X = Osrs_t
   Shift X , Left , 3
   X = X + Osrs_p
   Shift X , Left , 2
   X = X + Mode_reg

   Call I2c_write(bme280_adress , &HF4 , X)

   'BME280 lese Kalibrierwerte
   Call I2c_read(bme280_adress , &H88 , 24 )

   Dig_t1 = Wert_array(2)
   Shift Dig_t1 , Left , 8
   Dig_t1 = Dig_t1 + Wert_array(1)

   Dig_t2 = Wert_array(4)
   Shift Dig_t2 , Left , 8
   Dig_t2 = Dig_t2 + Wert_array(3)

   Dig_t3 = Wert_array(6)
   Shift Dig_t3 , Left , 8
   Dig_t3 = Dig_t3 + Wert_array(5)

   Dig_p1 = Wert_array(8)
   Shift Dig_p1 , Left , 8
   Dig_p1 = Dig_p1 + Wert_array(7)

   Dig_p2 = Wert_array(10)
   Shift Dig_p2 , Left , 8
   Dig_p2 = Dig_p2 + Wert_array(9)

   Dig_p3 = Wert_array(12)
   Shift Dig_p3 , Left , 8
   Dig_p3 = Dig_p3 + Wert_array(11)

   Dig_p4 = Wert_array(14)
   Shift Dig_p4 , Left , 8
   Dig_p4 = Dig_p4 + Wert_array(13)

   Dig_p5 = Wert_array(16)
   Shift Dig_p5 , Left , 8
   Dig_p5 = Dig_p5 + Wert_array(15)

   Dig_p6 = Wert_array(18)
   Shift Dig_p6 , Left , 8
   Dig_p6 = Dig_p6 + Wert_array(17)

   Dig_p7 = Wert_array(20)
   Shift Dig_p7 , Left , 8
   Dig_p7 = Dig_p7 + Wert_array(19)

   Dig_p8 = Wert_array(22)
   Shift Dig_p8 , Left , 8
   Dig_p8 = Dig_p8 + Wert_array(21)

   Dig_p9 = Wert_array(24)
   Shift Dig_p9 , Left , 8
   Dig_p9 = Dig_p9 + Wert_array(23)

   Call I2c_read(bme280_adress , &HA1 , 1 )

   Dig_h1 = Wert_array(1)

   Call I2c_read(bme280_adress , &HE1 , 8 )

   Dig_h2 = Wert_array(2)
   Shift Dig_h2 , Left , 8
   Dig_h2 = Dig_h2 + Wert_array(1)

   Dig_h3 = Wert_array(3)

   Dig_h4 = Wert_array(4)
   Shift Dig_h4 , Left , 4
   X = Wert_array(5)
   X = X And &HF
   Dig_h4 = Dig_h4 + X

   Dig_h5 = Wert_array(6)
   Shift Dig_h5 , Left , 4
   X = Wert_array(5)
   Shift X , Right , 4
   Dig_h5 = Dig_h5 + X

   Dig_h6 = Wert_array(7)
End Sub



Function Absolute_altitude(byval Pressure As Dword)
   Local X As Single

   'höhe = 288.15/0.0065*(1-(pressure/1013.25)^(1/5.255));

   X = Pressure
   X = X / 101325                                 '32bit
   X = X ^ 0.1902949
   X = 1 - X
   X = 44330.76923 * X
   X = X * 100                                    '32bit

   Absolute_altitude = X
End Function