ADAU1777 problem with more than 16 instructions
Hi,
I have a simple setup where Input 2 feeds 7 "General (2nd order)" filters and sends out OUT0. Similarly Input 3 feeds 7 "General (2nd order)" filters and sends out OUT1. The compiler says the instruction count is 16 out of 32.
When I add any additional blocks - which result in an instruction count of 17 or more - audio stops playing out of one of OUT0 or OUT1. Usually OUT1 goes silent.
Is this supposed to happen? Basically I can't use the DSP up to it's maximum 32 instructions.
I've tested all sample rates from 48 kHz up to 768 kHz and the problem is always there.
Thanks,
Michael
Integrated/Special Purpose A/D Converters
adau1777
Audio CODECs
Ok we figured it out (and it's not documented anywhere).
To access the full 32 instructions:
- increase the "Regulator Control" from 1.1 to 1.2 V
- enable the PLL and ensure the PLL output is 24.576 MHz
- set the "Core Clock" divider to 1
- set the "Main Clock" divider to 2
Regards,
Michael
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