Data Sheet

9. Serial command encoding
As described in Section 8, the Tic’s serial commands each use one of four formats: quick, 7-bit write,
32-bit write, and block read. This section explains how these four command formats are encoded as
sequences of bytes within TTL serial command packets.
The following examples are shown using the compact protocol, which is intended for cases where
the Tic is the only device connected to your serial line. Later on, this section also describes the Pololu
protocol, which can be used to daisy-chain a Tic on a single serial line with other devices (including
additional Tics).
For a reference implementation of these protocols, see the TicSerial class in our Tic Stepper Motor
Controller library for Arduino [https://github.com/pololu/tic-arduino].
Quick
command
A quick command sends no data and simply consists of the command byte.
Example: Halt and hold [https://www.pololu.com/docs/0J71/8#cmd-halt-and-hold]
command
0x89
7-bit write
command data
A 7-bit write command has a single byte of data containing a 7-bit value (the most-significant bit of the
data byte is always 0) that comes after the command byte.
Example: Set step mode [https://www.pololu.com/docs/0J71/8#cmd-set-step-mode] to 1/8 step
command data
0x94 0x03
Tic Stepper Motor Controller User’s Guide © 2001–2018 Pololu Corporation
9. Serial command encoding Page 135 of 150