Hi for your information here is the mapping used in MiniBrute (from firmware 1.0.2).
C0 = 16.35Hz -> 0V -> midi 12
C1 = 32.7Hz -> 1V -> midi 24
C2 = 65.4Hz -> 2V -> midi 36
C3 = 130.8Hz -> 3V -> midi 48
C4 = 261.62Hz -> 4V -> midi 60
C5 = 523.25Hz -> 5V -> midi 72
C6 = 1046.5Hz -> 6V -> midi 84
C7 = 2093Hz -> 7V -> midi 96
C8 = 4186Hz -> 8V -> midi 108
C9 = 8372Hz ->9V -> midi 120
