9. Maestro Settings Limitations

Mini Maestro serial baud rate limitations

On the Mini Maestro 12, 18, and 24, the following baud rates should not be exceeded, or the processor may become overloaded, causing degraded performance.

	10–100 Hz	111–250 Hz	333 Hz
Serial mode: UART/USB chained*	200 kbps	115.2 kbps	115.2 kbps
Serial mode: Dual-port	115.2 kbps	57.6 kbps	57.6 kbps

* Assuming bytes are not sent and received simultaneously, as required for the Pololu protocol.

Micro Maestro pulse length limitations (high pulse rates only).

Most servos are designed for 50 Hz operation. Unless you know that you need high pulse rates, you can safely ignore this section.

The Micro Maestro has a restricted maximum pulse length for pulse rates of 67 Hz and higher. The restriction depends on the Servos available setting and is enforced automatically by the Maestro Control Center.

The maximum pulse lengths in microseconds are given below:

	6 servos	5 servos	4 servos	1–3 servos
67 Hz	2448	2944	3000+	3000+
71 Hz	2272	2736	3000+	3000+
77 Hz	2112	2544	3000+	3000+
83 Hz	1936	2336	2944	3000+
91 Hz	1776	2144	2688	3000+
100 Hz	1616	1936	2448	3000+

Mini Maestro servo pulse length limitations (high pulse rates only)

Most servos are designed for 50 Hz operation. Unless you know that you need high pulse rates, you can safely ignore this section.

On the Mini Maestro 12, 18, and 24, pulse rates of 200–333 Hz put restrictions on the servo pulse lengths. These restrictions apply to all servo channels, even if some are set to a lower pulse rate using the Period multiplier feature.

The following tables show allowed minimum and maximum pulse lengths, in microseconds, for a variety of combinations of pulse rates and servo numbers. All enabled servos must always satisfy the restrictions on some table row, so the easiest way to follow the restrictions is to pick a row, then configure minimums and maximums for specific channels according to the restrictions given in that row. However, you do not need to specify the ranges of your servos in advance: you can switch some channels off or adjust their positions to access a wider range on other channels. If your settings happen to violate these restrictions, the servo period might increase and the units of speed and acceleration limits will change accordingly, but the operation of the Maestro will not be affected in any other way.

For example, with a Mini Maestro 24 running at 250 Hz (a 4 ms period), you may use 12 servos with a range of 576–2880 μs and 6 servos with a range of 64–2880 μs. The remaining 6 channels must each be off or have their mode set to Input or Output (not Servo).

Allowed pulse ranges at 333 Hz:
Servos Min Max 6 64 2328 6 192 2648 12 64 1752 12 384 2456 6/6 384/64 2072 18 64 1176 18 576 2264 24 768 2072

Allowed pulse ranges at 250 Hz:
Servos Min Max 6 64 3000+ 12 64 2752 12 384 3000+ 6/6 384/64 3000+ 18 64 2176 18 576 3000+ 12/6 576/64 2880 24 64 1600 24 768 3000+ 18/6 768/64 2688

Allowed pulse ranges at 200 Hz:
Servos Min Max 6 64 3000+ 12 64 3000+ 6/6 384/64 3000+ 18 64 3000+ 12/6 576/64 3000+ 24 64 2600 24 768 3000+ 18/6 768/64 3000+