SLAAE27 June   2021 MSP430FR2155 , MSP430FR2155

 

  1.   Trademarks
  2. 1Introduction
  3. 2Design Description
  4. 3Software
  5. 4Test Results
    1. 4.1 Stepper Motor Output
    2. 4.2 DC Motor Output
  6. 5Summary
  7. 6References

3 Software

Figure 3-1 show the software flow chart for the motor module:

  1. 5 V power input is required to generate the necessary on-board supplies for all logic operations.
  2. Software initialization tristates the motor driver outputs and puts the motor drivers to sleep mode. Default motor voltage, speed, direction, pulse-count, PWM frequency, and step-mode are set as shown in Figure 3-1.
  3. Tilt, focus, and iris motors are enabled as per the start or enable user variable for the respective motors.
    1. Tilt and focus motor: Direction, pulse-count (or number of steps) and micro-stepping are set for the respective motor. Outputs are enabled to drive the respective motor.
    2. Iris motor: Duty cycle required to achieve the required motor voltage is calculated and set. Output is enabled and PWM pulses are generated to drive the iris motor in the chosen direction.
  4. Operation is repeated until the pulse counter reaches zero or until time-out.
Figure 3-1 Software Flow Chart

The following steps are required to program the camera motor module:

  1. Pre-requisites: Download the software 'Motor_Module_Software' available at https://www.ti.com/lit/zip/slaae27. Install and launch the Code Composer Studio IDE. Unzip and import the Motor_Module_Software project in CCS.
  2. Variables: The control macros for controlling the speed, direction, step-mode, pulse-count and run-time for the motor drivers can be found in "Camera_Motor_EVM.h". These values can be set as per application requirements.
  3. Connections: Connect 5-V Power input to the motor control module. Connect a programmer from the PC (using MSP-FET JTAG or any MSP430 Launchpad) to the MSP430FR2155 on the motor module with jumper wires. It is required to connect GND, SBWTDIO, and SBWTCK.
  4. Program: In CCS, debug and build the code to program the motor module. This will run the code based on the input control macros from step 2.
  5. Using UART commands:
    1. Program the motor module’s MSP430FR2155 (as described in steps above).
    2. Hardware connections: Connect the UART lines (RX and TX) from any MSP430 Launchpad's programming header to the motor module’s UART pins.
    3. PC settings: Plug the MSP430 Launchpad to the USB port of the PC. Open any serial terminal and connect to the MSP430 serial port. Port settings: 115200 kbps, 8 bit, 1 stop, and no parity.
    4. Hex commands can be used to control the module as shown in Table 3-1, Table 3-2, and Figure 3-2.

Table 3-1 UART Commands
Command Hex Value Notes
Reset_Position 0x01 Sets motor position counter to 0
Read_Current_Position 0x02 Returns current motor position value
Step_Command 0x04 Steps motor forward or backwards. Send 16-bit signed number for # of steps and direction. (+ = Clockwise, - = Counter Clockwise)
Set_Position 0x05 Sets motor to a desired position. Send 16 bit signed number to indicate target position.
Table 3-2 Motor Enable
Motor Motor Select Bit
Focus motor 0
Tilt motor 1
GUID-20210529-CA0I-ZR9K-JDMM-BDDNC0J3PD65-low.jpg Figure 3-2 UART Commands