On Mon, Jun 10, 2013 at 8:07 PM, Joe Wronski <jwronski@stillwatereng.net> w=
rote:
> On 6/10/2013 10:03 AM, Manu Abraham wrote:
>> One thing that I don't understand is, why he does this: " static
>> uint8_t old_AB =3D 0;" that would loose the previous state altogether,
>> wouldn't it ?
>
> No, the "=3D0" is only assigned when the static old_AB is allocated and
> initialized, after that, it retains it's value as set by the "old_AB =3D"
> assignments in read_encoder()


Please note the next line:


  static uint8_t old_AB =3D 0;
  /**/
  old_AB <<=3D 2;                   //remember previous state

Once you initialize the variable to 0, then there is no way that it
can remember
the previous state.


Also note:

enc_states[] is a n array with 16 elements in it.


Since the array index is & with 0x0f, it makes sense that 4 bits used in th=
e
array index variable.

So, given these;  I can't seem to make sense how it remembers the
previous state,
so that the array index maximum can be reached.


Regards,

Manu
--=20
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