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# stepgen

Stepper motor speed ramp generator.

Given acceleration, target speed and target step to stop
at, generates acceleration or deceleration profile for the stepper motor, in the form of delays
between steps.

Uses algorithm from "[Generate stepper-motor speed pro les in real time][1]" paper by David Austin.

## Examples
```rust
use stepgen::Stepgen;

let mut stepper = Stepgen::new(1_000_000);

stepper.set_acceleration(1000 << 8).unwrap(); // 1000 steps per second per second
stepper.set_target_speed(800 << 8).unwrap(); // 800 steps per second (4 turns per second)
stepper.set_target_step(1000).unwrap(); // stop at step 1000

// Take 99 steps
for _ in 0..99 {
    println!("{}", stepper.next().unwrap());
}

assert_eq!(99, stepper.current_step());
assert_eq!(113621, stepper.current_speed());
assert_eq!(2242, (stepper.next().unwrap() + 128) >> 8); // delay for 100th step, rounded to the nearest integer
```
### Note on numbers

In few APIs, stepgen keeps numbers as fixed-point numbers, using least significant 8 bits
for the fractional part and the remaining bits for the integral part.

[1]: http://www.embedded.com/design/mcus-processors-and-socs/4006438/Generate-stepper-motor-speed-profiles-in-real-time

## License

Licensed under either of

 * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
 * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)

at your option.

### Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any
additional terms or conditions.