Proteus doesn't show the value of float variables and does not attribute values to them
If your debug files are COFF format, please check this link: http://support.labcenter.co.uk/forums/viewtopic.php?f=9&amp;t=3770&amp;p=12623&amp;hilit=+dt_float+#p12623

Double click on the MCU in the ISIS workspace to brings up the edit component window. In the "other properties" edit box, add DT_FLOAT=MICROCHIP_BIGENDIAN