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running, instead of being affected by settings that you might have set previously in an old version of
your code. The bytes shown above are the command byte for the “Reinitialize” command followed by
a cyclic redundancy check (CRC) byte.
Description: Disable CRC
Bytes: 0x8B 0x04 0x7B 0x43
This command disables the cyclic redundancy check (CRC) feature of the Motoron (documented
in
). The CRC feature is enabled by default to make the Motoron less likely to execute
incorrect commands when there are communication problems. Disabling CRC makes it easier to get
started writing code for the Motoron because you do not have to implement the CRC computation
or append CRC bytes to each command you send. Once you have gotten your system to work, you
might consider implementing CRC and removing this command to make things more robust. This is
an example of the more general “Set protocol options” command, and the last byte shown above is a
CRC byte.
Description: Clear reset flag
Bytes: 0xA9 0x00 0x04
This command clears (sets to 0) a bit in the Motoron called the “Reset flag”. This flag gets set to 1
after the Motoron powers on or experiences a reset, and with the default configuration it is considered
to be an error, so it prevents the motors from running.This is an example of the more general “Clear
latched status flags” command, and there is no CRC byte appended because we disabled the CRC
feature above.
The reset flag exists to help prevent running motors with incorrect settings. In case the Motoron itself
gets reset while your system is running, the Reset flag will be set and the motors will not run.
Initialization sequence (with CRC)
This is similar to the initialization sequence above, except it leaves CRC enabled.
Description: Reinitialize
Bytes: 0x94 0x74
Description: Clear reset flag
Bytes: 0xA9 0x00 0x04
The bytes at the end of each command are CRC bytes. Instead of hard coding those bytes, you
should be able to calculate each one by applying the CRC algorithm to the command and data bytes
immediately before it.
Pololu Motoron Motor Controller User’s Guide
© 2001–2022 Pololu Corporation
3. Getting started
Page 22 of 67