Loops and Transitions

By default, FociStm / PatternStm play back the same pattern sequence infinitely. To make the playback count finite, proceed as follows.

Finite loops

The playback count is specified with loop_behavior of FociStmOption and the like. LoopBehavior::Infinite (default) loops infinitely, while LoopBehavior::Finite(n) plays back n times (up to 65535 times) and then stops. Note that on stopping, the last pattern continues to be output.

An important point is that a finite loop takes effect only when switching to a bank different from the current one.

Rust

// Play the circular motion only 3 times, then stop.
// A finite loop (and non-immediate transition) only fires when switching to a
// different bank, so write to bank B1 instead of the current B0.
client.send(FociStm::new(
    config,
    &foci,
    FociStmOption {
        loop_behavior: LoopBehavior::Finite(NonZeroU16::new(3).unwrap()),
        bank: PatternBank::B1,
        transition_mode: TransitionMode::SyncIdx,
        ..Default::default()
    },
)).await?;

Python

# Play the circular motion only 3 times, then stop.
# A finite loop (and non-immediate transition) only fires when switching to a
# different bank, so write to bank B1 instead of the current B0.
await client.send(
    FociStm(
        config,
        foci,
        FociStmOption(
            loop_behavior=LoopBehavior.Finite(3),
            bank=PatternBank.B1,
            transition_mode=TransitionMode.SyncIdx,
        ),
    )
)

C#

// Play the circular motion only 3 times, then stop.
// A finite loop (and non-immediate transition) only fires when switching to a
// different bank, so write to bank B1 instead of the current B0.
await client.SendAsync(new FociStm(
    new SamplingConfig(50.0f * Hz * foci.Length),
    foci,
    new FociStmOption
    {
        LoopBehavior = LoopBehavior.Finite(3),
        Bank = PatternBank.B1,
        TransitionMode = TransitionMode.SyncIdx,
    }
));

Transition timing

The timing at which the playback target switches to a bank is specified with transition_mode. The modes that can be used are constrained by the loop setting (loop_behavior) of the destination bank.

Modes available when the destination is an infinite loop.

• Immediate (default): switches the bank immediately after the write.
• Ext: extended mode. Automatically switches to the next bank when playback within the bank finishes.

Modes available when the destination is a finite loop.

• SyncIdx: switches at the timing when the playback index of the target bank returns to 0.
• SysTime { time }: switches at the specified device time time (TransitionMode.SysTime(time) in Python / C#).
• Gpio(GpioIn): switches on the trigger of the specified GPIO input pin.

Note

The various loop and transition constraints exist in order to synchronize multiple devices.

As with the loop setting, the transition timing takes effect only when a bank is switched.

For fine-grained control such as preloading the next output into another bank in advance and switching at an arbitrary timing, refer to the low-level commands in the API reference.