jcarruthers
Well-known member
mxxx —*thanks for all this —*very useful as ever. Have progressed since last week.
Sent you a PM to continue our conversation.
Sent you a PM to continue our conversation.
Which I don't understand, frankly; but in practice yes, use a TL072 in there and things go wrong. Use the above op-amps (greater current drive?) and it works. It is sending a buffered, stable reference voltage into the Teensy 3.1 AREF pin.
Yes, it is 3.3v
I have trying to use the external vref for the output on my list, and see if there is a worthwhile reduction in noise. When it was originally designed, I had no idea that there would be the option.
inline float fastpow2 (float p)
{
float offset = (p < 0) ? 1.0f : 0.0f;
float clipp = (p < -126) ? -126.0f : p;
int w = clipp;
float z = clipp - w + offset;
union {
uint32_t i;
float f;
} v = { cast_uint32_t ( (1 << 23) *
(clipp + 121.2740575f + 27.7280233f / (4.84252568f - z) - 1.49012907f
* z) )
};
return v.f;
}
pre_expo_conv = CV_IN[4] / tuning_cal;
post_expo_conv = fastpow2(pre_expo_conv);