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H-Bridge
========
.. image:: l293d.jpg
:width: 300
:align: center
*L293D H-Bridge, used on esieabots from 2020 to 2022*
Your esieabot is equipped with a bridge that allows it to control its 2 :doc:`DC motors </understand/dcmotor/dcmotor>` in all directions. On esieabots from 2020 to 2022, it is an L293D from STMicroelectronics. On esieabots from 2023 and newer, it is a DRV8411 from Texas Instruments, integrated into the :doc:`add-on board </understand/add-on-board/add-on-board>`. The components differ greatly in terms of performance, but their operation is very similar.
Operation
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An H-bridge is a component that allows a motor to rotate in two directions. On the esieabot, the H-bridge is "dual" because it can control 2 motors at the same time.
.. image:: https://upload.wikimedia.org/wikipedia/commons/d/d4/H_bridge.svg
:width: 400
:align: center
Depending on which inputs are activated, the voltage will go in one direction or the other, causing the motors to rotate in one direction or the other.
.. image:: https://upload.wikimedia.org/wikipedia/commons/f/f2/H_bridge_operating.svg
:width: 400
:align: center
*Cyril BUTTAY, CC BY-SA 3.0 <http://creativecommons.org/licenses/by-sa/3.0/>, via Wikimedia Commons*
Connections
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For each motor, the following inputs and outputs must be connected:
- "Enable" input: enables or disables a motor, *only present on the L293D, on esieabot models from 2020 to 2022 inclusive*
- "Input 1 (or 3)" input: activates the motor in one direction
- "Input 2 (or 4)" input: activates the motor in the other direction
- "Output 1 (or 3)" output: one of the motor terminals
- "Output 2 (or 4)" output: the other motor terminal
- "Fault" output: detects a problem with the H-bridge, such as overcurrent or overtemperature, *only present on the DRV8411, on esieabot models from 2023 and newer*
.. note:: Note that there is no defined direction through the H-bridge. The motor's + and - terminals as well as the forward/backward direction are purely arbitrary.
.. note:: If you are using an add-on board, you can find the GPIOs used in its :doc:`documentation </understand/add-on-board/add-on-board>`.
Technical Specifications
-------------------------
The complete datasheet for the L293D (esieabot 2020 to 2022) can be found here: https://www.st.com/resource/en/datasheet/l293d.pdf.
The complete datasheet for the DRV8411 (esieabot 2023 and newer) can be found here: https://www.ti.com/lit/ds/symlink/drv8411.pdf.