here is my question again,...look inside , thanks

[gunking88]

part of my code..
...
signed int16 error=0; // real error read from ADC
...
signed int16 vout=0;
signed int16 vref=204; //204 in 8 bits for 4V, output at 12V

every 50us following executes
...
vout=read_adc(adc_read_only);
error=vref-vout;//difference between ref and output
if (error>11){error=11;}
if (error<-10){error=-10;}

here is my question,
I set vout=FF, and I used the watch to check error, I found
error=FFCD, after error=vref-vout
but error=0X0B after if if (error>11){error=11;}

it seems that the error was treated as positive value here.
why this happened? it is the problem of the debugger mode or my code?
thanks..

[Guest]

try this:

if ((signed int16)error>(signed int16)11) {error==11;}

From my experiance with the compiler it is entirely possible that it thinks error is an unsigned value. So if this works I would go one more step and try:

vout=(signed int16)read_adc(adc_read_only);

Also try different versions of the compiler, some versions do things different than others.


Trampas

[Ttelmah]