User Manual

At the minimum acceleration setting of 1, the servo output takes about 3 seconds to move smoothly

from a target of 1 ms to a target of 2 ms.

The acceleration setting has no effect on channels configured as inputs or digital outputs.

Set PWM (Mini Maestro 12, 18, and 24 only)

Compact protocol: 0x8A, on time low bits, on time high bits, period low bits, period high bits

Pololu protocol: 0xAA, device number, 0x0A, on time low bits, on time high bits, period low bits,

period high bits

This command sets the PWM output to the specified on time and period, in units of 1/48 μs. The on

time and period are both encoded with 7 bits per byte in the same way as the target in command 0x84,

above. For more information on PWM, see Section 4.a. The PWM output is not available on the Micro

Maestro.

Get Position

Compact protocol: 0x90, channel number

Pololu protocol: 0xAA, device number, 0x10, channel number

Response: position low 8 bits, position high 8 bits

This command allows the device communicating with the Maestro to get the position value of a

channel. The position is sent as a two-byte response immediately after the command is received.

If the specified channel is configured as a servo, this position value represents the current pulse width

that the Maestro is transmitting on the channel, reflecting the effects of any previous commands,

speed and acceleration limits, or scripts running on the Maestro.

If the channel is configured as a digital output, a position value less than 6000 means the Maestro

is driving the line low, while a position value of 6000 or greater means the Maestro is driving the line

high.

If the channel is configured as an input, the position represents the voltage measured on the channel.

The inputs on channels 0–11 are analog: their values range from 0 to 1023, representing voltages from

0 to 5 V. The inputs on channels 12–23 are digital: their values are either exactly 0 or exactly 1023.

Note that the formatting of the position in this command differs from the target/speed/acceleration

formatting in the other commands. Since there is no restriction on the high bit, the position is formatted

as a standard little-endian two-byte unsigned integer. For example, a position of 2567 corresponds to

a response 0x07, 0x0A.

Note that the position value returned by this command is equal to four times the number displayed in

5. Serial Interface Page 56 of 99