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From: tom00 on 13 Nov 2009 07:18
Hello all!

I have to implement a Schmitt trigger in software on a DSP. I was thinking
a while about a good implantation, but I just came to the simple solution
with has nested if conditions (See Pseudo code below). Does anyone has a
faster code??


-Thomas



for n = 1:length(x)
if flag
if x(n) > th
do something
flag = 0;
end
else
if x(n) < -th
do soming else
flag = 1;
end
end
end

From: Christen Fihl on 13 Nov 2009 07:26
Table lookup like

State = Array [0..1] [0..15] of 0..1

State[0] = '0000000000011111'
State[1] = '0000011111111111'

Y := State[Y] [X]

X limited between 0..15, else bigger table

Christen Fihl


From: Vladimir Vassilevsky on 13 Nov 2009 13:29


tom00 wrote:

> Hello all!
>
> I have to implement a Schmitt trigger in software on a DSP. I was thinking
> a while about a good implantation, but I just came to the simple solution
> with has nested if conditions (See Pseudo code below). Does anyone has a
> faster code??
>
>
> -Thomas
>
>
>
> for n = 1:length(x)
> if flag
> if x(n) > th
> do something
> flag = 0;
> end
> else
> if x(n) < -th
> do soming else
> flag = 1;
> end
> end
> end

^^^^^^^^^^^^^^^^^^^^^^^^^
Fie, stupident solution.




Here we go:

const s16 fubar[] = { nonsense, -nonsense };
const s16 void (*do_something[])() = { something_ , else_ };


s16 *x = blablabla;
s16 th = 0;

while(length--)
{
th = fubar[u16 state = ((u16)(*x++ +th)) >> 15];
do_something[state];
}


VLV
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