You have to handle that in your own code, if the number is above 128 its negative (0 - (b0 - 128))if it outputs directly to degrees celcius, how can it handle negative degrees? variable overflow?
READTEMP12, pin, w0
w0=w0*10/16
Degrees = w0 /10
Tenths = w0//10
SEROUT pin, N2400 (“Temp = “,#degrees,”.”,#tenths)