SLAAEQ7 January   2026 MSPM0G3507 , MSPM0G3519

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
    1. 1.1 Dual Wheel Projector System
    2. 1.2 MSPM0 Requirements
  5. 2Color Wheel Control in MSPM0
    1. 2.1 Software Structure
    2. 2.2 External Edge Difference Capture
      1. 2.2.1 Input Filter with Comparator
    3. 2.3 Internal Position Loop Control
    4. 2.4 Speed Control Output
  6. 3Test and Evaluation Method
    1. 3.1 Test System Setup
    2. 3.2 Performance Evaluation
  7. 4Summary
  8. 5References

1.2 MSPM0 Requirements

In projector dual wheel control applications, MSPM0 controls the position synchronization of the color wheel by outputting speed control signal to the MCF8316.

Figure 1-2 is the control diagram of MSPM0 in a wheel control application. The MSPM0 uses the same method to control two wheels. The FW and DW Index is the color wheel position feedback signal, when the wheel rotates to the set position, the position detection module trigger a pulse output. FW and DW Sync Signal is the input synchronous signal from DLPC, this is also a pulse signal. MSPM0's timer can calculate the two pulse signal's edge position error by using the hardware capture feature. The PWM speed signal is controlled through the phase loop calibration algorithm module, thereby controlling the speed of the color wheel to make sure that the phase difference between the FW/DW Index pulse edge and FW/DW sync pulse edge is fixed.

Optionally, MSPM0 can capture the sync signal and MCF8316's feedback PWM signal's duty and period information by the capture function of the timer.

MSPM0 Wheel Control Diagram Figure 1-2 MSPM0 Wheel Control Diagram

Based on the above requirements, wheel control application requires at least three timers to control the two color wheels. Table 2-3 is dual wheel control MSPM0 resource requirement.

Table 1-1 Dual Wheel Control MSPM0 Resource Requirement
Function Peripherals Description
MCF8316 Configuration I2C bus MCF8316 need to configure to different address to share the same I2C bus
Edge difference capture Timer0 CC0 and CC1 Each color wheel needs a timer with two capture channels
Timer1 CC0 and CC1
Speed control Timer2 CC0 and CC1 Two MCF8316s can use a single timer with two compare channel to output PWM
Phase loop calibration CPU and MATHACL Calibration loop algorithm
Signal input filter COMP Optional, convert the analog position signal to digital signal
Period and duty capture Timer3 CC0 and CC1 Optional, capture the color wheel speed, speed of the control signal and duty
Task scheduler Systick Periodic calibration task
Note: For edge capture function, if input signal is an analog signal, a MSPM0 internal comparator can be added to the signal chain to convert the analog signal to digital signal. MSPM0 internal comparator has a build-in reference 8-bit DAC that can be used for logic level control, also hysteresis and filter feature can be used for analog signal filter and output a stable digital signal to timer.