PCMD3180: biquad filters

Hi Jack,

The biquads don't have a true "enable" or "disable" bit. Rather the biquads are all set to be an All-Pass filter by default and when you want to use the filter you upload the new coefficients to the device. To turn it back off, you re-upload the coefficients to return the filter to be All-Pass. Here's a code example below:

#default all-pass values

w 98 08 7f ff ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

# write desired filter coefficients i.e. enable biquad

w 98 08 7f ff ff ff 8b ce 5f 5c 6a 64 9a 4b 74 31 a0 a4 95 9b 65 b5

# rewrite default values to change the filter to all-pass i.e. disable biquad

w 98 08 7f ff ff ff 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Best regards,
Jeff McPherson