Data Sheet

Optional connections
The Tic’s 5V (out) pin provides access to the output of the Tic’s 5V regulator, which also powers
the Tic’s microcontroller and the red and yellow LEDs. You can use the Tic’s regulator to power your
microcontroller or other serial device if the device does not draw too much current (see Section 5.7).
The VM pin provides access to the Tic’s power supply after the reverse-voltage protection circuit, and
this pin can be used to provide reverse-voltage-protected power to other components in the system if
the Tic supply voltage is within the operating range of those components. Note: this pin should not be
used to supply more than 500 mA; higher-current connections should be made directly to the power
supply. Unlike the 5V (out) pin described above, this is not a regulated, logic-level output.
The ERR pin of the Tic is normally pulled low, but drives high to indicate when an error is stopping
the motor. You can connect this line to an input on your microcontroller (assuming it is 5V tolerant) to
quickly tell whether the Tic is experiencing an error or not. Alternatively, you can query the Tic’s serial
interface to see if an error is happening, and which specific errors are happening. For more information
about the ERR pin, see Section 5.4.
The RST pin of the Tic is connected directly to the reset pin of the Tic’s microcontroller and also has
a 10 kΩ resistor pulling it up to 5 V. You can drive this pin low to perform a hard reset of the Tic’s
microcontroller and de-energize the stepper motor, but this should generally not be necessary for
typical applications. You should wait at least 10 ms after a reset to transmit to the Tic.
Connecting a serial device to multiple Tics
The Tic’s serial protocol is designed so that you can control multiple Tics using a single TTL serial port.
Before attempting to do this, however, we recommend that you first get your system working with just
one Tic as described above.
Next, make sure that the serial device and the Tics all share a common ground, for example by
connecting a GND pin from the device to a GND pin on each of the Tics. Make sure that the TX pin on
the serial device is connected to the RX pin of each Tic (via a level shifter if needed).
If you attempt to run the SerialSpeedControl example in this configuration, you should see each of your
Tic controllers moving their stepper motors in unison. That example uses the Tic’s Compact Protocol,
which is only suitable for controlling one device. The Compact Protocol commands do not contain
a device number, so every Tic device that sees a Compact Protocol command will obey it. This is
probably not what you want.
To allow independent control of multiple Tics, you should use the Tic Control Center to configure each
Tic to have a different device number. Then you should change your code to use the Pololu Protocol
as described in Section 9. If you are using our Tic Arduino library, can declare one object for each Tic,
and specify the device number of each Tic, by writing code like this at the top of your sketch, which
Tic Stepper Motor Controller User’s Guide © 2001–2018 Pololu Corporation
4. Setting up the controller Page 35 of 150