I am trying to force the I2S digital output (pin 26 on an ADAU1761) to output a PWM signal.
In order to succeed this I am forcing the I2S output to certain DC values by using DC sources in SigmaStudio.
Ideally, I would like to enable the first bit of the I2S output and then one by one add the rest of the 23 I2S bits.
However, I am a bit confused on how the I2S values map to DC voltages.
I have figured out that a -1 DC voltage value will force the DIG0 to enable the MSB of the I2S output.
Then in order to keep activating the rest of the I2S bits in a sequence I am using the values in the following table:
|DC voltage value (5.23 format)||I2S bit|
|below -1||first MSB enabled|
|-1 (-1/2^0)||first MSB enabled|
|-0.5 (-1/2^1)||first 2 MSB enabled|
|-0.25 (-1/2^2)||first 3 MSB enabled|
|-0.125 (-1/2^3)||first 4 MSB enabled|
|-0.0625 (-1/2^4)||first 5 MSB enabled|
|-0.03125 (-1/2^5)||first 6 MSB enabled|
|-0.015625 (-1/2^6)||first 7 MSB enabled|
|?||first 8 MSB enabled|
|?||first 9 MSB enabled|
|?||first 10 MSB enabled|
however I cannot seem to activate more than 7 MSBs in a row. The DC voltage cannot output a value as low as necessary in order to activate the rest of the bits.
Any idea how I could activate the rest of the I2S bits?
How convention does SigmaStudio use in order to map the I2S data to DC values?