cv.slew already outputs a linear ramp. you donāt have to worry about the rate. i assume you just to turn the ramp into a half-cycle sine scaled to [0, 1].

call the linear ramp output `x`

, you want `(cos((x+1) * pi) + 1) / 2`

```
y = fix16_cos(fix16_mul(fix16_add(x, fix16_one), fix16_pi)
```

and then scale back to [0, 1]

```
y = fix16_add(y, fix16_one) >> 1
```

(untested!)

note that there are different options for `libfixmath`

sine approximation that can be selected in the preprocessor. to use the LUT define `FIXMATH_SIN_LUT`

somewhere. otherwise there is a less accurate parabola appoximation and a more accurate higher order polynomial