Filter cutoff - keyboard tracking

I did some work on the filter today. First, I switched from a 100k to a 36k resistor between the CV input and the 0-5V CV. This changes the filter range from 5 octaves to 14 octaves, like the original juno filter. 

I then added pitch to the filter cutoff cv in the matrix, making sure to compensate for the fact that the pitch range is 10 octaves and the filter is 14 octaves. Instant success! The filter tracked almost perfectly from the start, now the output amplitude stays constant between notes and most of the annoying clicks when changing note is gone!

I also added pitch bend. At the moment it has a lot of stepping when running from my MPK25, I will retry with pitch from the Little Phatty, I think this is only a midi issue. There is some noise on the pitch bend too. I first suspected that it was digital noise from the SPI bus, but when I did a small program change that updated the DCOs without actually changing the pitch, the clicks went away. Thus, they are entirely related to either DCO artifacts or the missing filter tracking.