Frequency register
From Famitracker Wiki
A frequency register is a register located in the RAM that calculates the pitch of a note. In the case of DPCM, FDS, Namco 163 and Konami VRC7 channels, a higher frequency register value results in a higher pitch. For all other channels, a higher frequency register value results in a lower pitch.
Here are a few tables listing the frequency registers of different notes.
