I've modified the ASM analogue in/out Talk through on an ADSP21369 EZKIT.
to do some tests.
In the sport isr for the data stream in the right channel I've effectively added the following
r10 = dm(RXSP0A); //Read ADC Value
f0 = 0.9; //load f0 with scaling value
f1 = float r10; //convert adc value to float
f2 = f1 * f0; //do multiply
r12 = fix f2; // float to fixed
dm(TXSP2B) = r12; //write to dac.
Now if the scaling value is <1 i get a scrachy audio signal in the right channel rather than an attenuated level.
when I multiply by 0.5 then by 2.0 i get a good signal.
When I multiply by 1 then i get a good signal.
When i watch the data in the core register watch window it looks correct.
and using a calculator i get the same but obviusly i'm doing something wrong.
Any Ideas before i pull my hair out.
Also i've not done any analog dsp assembler before is the above ok?