User Guide

Commands
The command byte is the second byte of the packet. There are four possible commands in
packetized serial mode. Each is followed by one byte of data
0: Drive forward motor 1 (decimal 0, binary 0b00000000, hex 0h00)
This is used to command motor 1 to drive forward. Valid data is 0-127 for off to full forward
drive. If a command of 0 is given, the Sabertooth will go into power save mode for motor 1 after
approximately 4 seconds.
1: Drive backwards motor 1 (decimal 1, binary 0b00000001, hex 0h01)
This is used to command motor 1 to drive backwards. Valid data is 0-127 for off to full reverse
drive. If a command of 0 is given, Sabertooth will go into power save mode for motor 1 after
approximately 4 seconds.
2: Min voltage (decimal 2, binary 0b00000010, hex 0h02)
This is used to set a custom minimum voltage for the battery feeding the Sabertooth. If the
battery voltage drops below this value, the output will shut down. This value is cleared at startup,
so much be set each run. The value is sent in .2 volt increments with a command of zero
corresponding to 6v, which is the minimum. Valid data is from 0 to 120. The function for
converting volts to command data is
Value = (desired volts-6) x 5
3: Max voltage (decimal 3, binary 0b0000011, hex 0h03)
This is used to set a custom maximum voltage. If you are using a power supply that cannot sink
current such as an ATX supply, the input voltage will rise when the driver is regenerating
(slowing down the motor) Many ATX type supplies will shut down if the output voltage on the
12v supply rises beyond 16v. If the driver detects an input voltage above the set limit, it will put
the motor into a hard brake until the voltage drops below the set point again. This is inefficient,
because the energy is heating the motor instead of recharging a battery, but may be necessary.
The driver comes preset for a maximum voltage of 30V. The range for a custom maximum
voltage is 0v-25v. The formula for setting a custom maximum voltage is
Value = Desired Volts*5.12
If you are using any sort of battery, then this is not a problem and the max voltage should be left
at the startup default.
4: Drive forward motor 2 (decimal 4, binary 0b00000100, hex 0h04)
This is used to command motor 2 to drive forward. Valid data is 0-127 for off to full forward
drive. If a command of 0 is given, the Sabertooth will go into power save mode for motor 2 after
approximately 4 seconds.
5: Drive backwards motor 2 (decimal 5, binary 0b00000101, hex 0h05)
This is used to command motor 2 to drive backwards. Valid data is 0-127 for off to full reverse
drive. If a command of 0 is given, the Sabertooth will go into power save mode after
approximately 4 seconds.