SLVA488B January   2014  – January 2021 DRV8434 , DRV8811 , DRV8818 , DRV8821 , DRV8824 , DRV8825

 

  1.   Trademarks
  2. 1Introduction and Problem Statement
  3. 2Stepper Motor Control High Level Functions
    1. 2.1 STEP Actuation: Acceleration, Speed Control and Deceleration Profiles
    2. 2.2 Accelerating the Motor
    3. 2.3 Stepper Speed
    4. 2.4 Decelerating the Motor
    5. 2.5 Speed Change
    6. 2.6 Position Control: Number Of Steps
    7. 2.7 Homing the Stepper
  4. 3I2C Protocol and Communications Engine
    1. 3.1 GPIO CONFIG
    2. 3.2 STEPPER CONFIG
    3. 3.3 GPIO OUT
    4. 3.4 Current Duty Cycle
    5. 3.5 START STEPPER
  5. 4Application Schematic
  6. 5Revision History

3 I2C Protocol and Communications Engine

In order to program the device parameters and the stepper motion engine profiles, an I2C protocol was chosen. The way it was designed, up to four controllers can be cascaded with only two communication lines and two address selector lines.

The I2C protocol is the typical three byte packet where the first byte is the target address, the second byte is the register address and the third byte is the data. There are 21 possible address register which can be accessed.

GUID-A0017733-4BC7-4D1A-BED8-4D32FCB44B5C-low.gifFigure 3-1 Parameters Table

The variables residing on addresses 0x00 to 0x0F have been discussed on previous sections. The other addresses are a combination of parameters as well as actions.