Probleme beim Funktionsaufruf (Bascom)

Hallo zusammen,

im folgenden Code bekomme ich beim Compilieren den Fehler "Source 
variable does not match the target variable" für die Zeile 23 mit dem 
Aufruf der Funktion Readds1820. Warum?

Viele Grüße
  Holger



$regfile = "ATtiny2313.dat"
$crystal = 4000000

Const Warntemp = 25
Const Skip_rom = &HCC
Const Convertt = &H44
Const Read_ram = &HBE

Declare Function Readds1820 As Integer

Dim Ds1820 As Integer

Config Pinb.0 = Output
Config Pinb.3 = Output
Set Portb.3
Config 1wire = Portd.6

Config Timer1 = Pwm , Pwm = 8 , Compare A Pwm = Clear Down , Compare B 
Pwm = Disconnect , Prescale = 1
Compare1a = 0

Led Alias Portb.0

Ds1820 = Readds1820

Do
Loop                                                        'zurück

End                                                         'end program


Function Readds1820 As Integer
  Dim Temp As Integer

  1wreset
  1wwrite Skip_rom
  1wwrite Convertt
  Waitms 300
  1wreset
  1wwrite Skip_rom
  1wwrite Read_ram
  Temp = 1wread(9)
  Shift Temp , Right
  If Temp > 127 Then Temp = Temp - 256

  If Temp < Warntemp Then Reset Led Else Set Led
  Readds1820 = Temp
End Function