float matematica

[granel]

hi, receive modbus 0x3e5c2900 , it is float ieee avr mega8a,
need to do polynom: y = -273265x6 + 756654x5 - 773979x4 + 348564x3 - 64344x2 + 13057x + 219.74;

have my function, if insert float like 0.77 or other -- all ok,
if insert 0x3F 45 1E B8=0.77 have bad result ((
Dont understad why??
Check using mikroCpro funktion : FloatToStr(myFloat, myStringOut); -->>
bad result
FloatToStr(0x3F451EB8, myStringOut);
for(i=0; i<15; i++) UART1_Write(myLevelOut);
//31 2E 30 36 31 34 39 34 65 39 00 00 70 79 4E == 1.061494e9..pyN



good result
FloatToStr(0.77, myStringOut);
for(i=0; i<15; i++) UART1_Write(myLevelOut);
//37 2E 36 39 39 39 39 39 65 2D 31 00 70 79 4E == 7.699999e-1.pyN

were my mistake??