SLAU893B October 2023 – July 2024 MSPM0C1103 , MSPM0C1103-Q1 , MSPM0C1104 , MSPM0C1104-Q1
TIMA provides the option of generating complimentary PWM outputs with deadband insertion (nonoverlapping transitions in complimentary PWM signals) from a signal PWM reference signal. Deadband is useful for applications with half-bridge control to avoid shoot-through conditions, such as motor driver or inverter-based applications.
The reference signal is generated on the TIMAx_Cy signal, and the complimentary signal is generated on TIMAx_CyN, where x is the timer instance and y is the CCP output channel. For instances, a reference PWM signal generated on TIMA0 CCP output channel 2 will produce complimentary output signals on TIMA0_C2 and TIMA0_C2N.
The deadband control register (TIMAx.DBCTL) is programmed with the deadband mode and timing information. The deadband mode is selected using the M1_ENABLE bit, and the timing information to control the deadband width in TIMCLK cycles is selected by the RISEDELAY and FALLDELAY bit fields. RISEDELAY and FALLDELAY are a function of the rising or falling edge delay to or from the reference PWM.
See Table 15-18 for the configuration and relationship between deadband mode and deadband width settings.
Deadband Mode | Bitfield | Description | Counting Mode |
---|---|---|---|
Mode 0 | M1_ENABLE = 0 | RISEDELAY is applied from rising edge of reference PWM to rising edge of TIMAx_Cy signal.
FALLDELAY is applied from falling edge of reference PWM to rising edge of CxN signal. |
Any |
Mode 1 | M1_ENABLE = 1 | RISEDELAY is applied from falling edge of TIMAx_CyN signal to rising edge of reference PWM.
FALLDELAY is applied to falling edge of reference PWM to rising edge of TIMAx_CyN signal. |
Up/down counting mode only |
Deadband timing equation and example
The equations for configuring RISEDELAY and FALLDELAY from TIMCLK frequency and deadband timing is shown in Equation 14 and Equation 15.
For example, if 400ns of deadband is required when using a TIMCLK frequency of 80MHz, and Mode 1 is used with center-aligned PWMs to generate equal deadband every PWM period, then RISEDELAY = FALLDELAY = (80MHz) * (400ns) = 32.
Complimentary PWM with Deadband Configuration
Configure a PWM output for an edge-aligned PWM (Section 15.2.5.2.1) or center-aligned PWM (Section 15.2.5.2.2) for any CCP output channel in TIMA.
Example 1 - Complimentary PWM outputs with deadband using edge-aligned PWM in down-counting mode
For edge-aligned PWM, Mode 0 can only be used for deadband insertion mode. See Figure 15-32 for inserting configurable deadband using down counting mode, TIMA output channel 0, and edge-aligned PWM.Example 2- Complimentary PWM outputs with deadband using center-aligned PWM
For center-aligned PWM, Mode 0 or Mode 1 can be used for deadband insertion mode. See Figure 15-33 for inserting configurable deadband using up/down counting mode, TIMA output channel 0, and center-aligned PWMs with deadband.