0
3
3
0
TBPRD-3
TBPRD-3
TBPRD
T
pwm
Figure 4-10. Up-Down Count Duty Cycle Range Limitation Example (HRPCTL[HRPE]=1)
Note
If the application has enabled high-resolution period control (HRPCTL[HRPE]=1), the duty cycle must
not fall within the restricted range. Otherwise, there will be undefined behavior on the ePWM output.
4.2.3.4 High Resolution Period
High resolution period control using the MEP logic is supported on devices with a Type 1 ePWM module via the
TBPRDHR(M) register.
Note
When high-resolution period control is enabled, the ePWMxB output will have +/- 1 TBCLK cycle jitter
in up-count mode and +/- 2 TBCLK cycle jitter in up-down count mode.
The scaling procedure described for duty cycle in
applies for high-resolution period as well:
Assumptions for this example:
System clock , SYSCLKOUT
= 11.1 ns (90 MHz)
Required PWM frequency
= 175 kHz (TBPRD value of 514.286)
Number of MEP steps per coarse step at 180 ps (MEP_ScaleFactor) = 61 (11.1 ns/180 ps)
Value to keep TBPRDHR within range of 1-255 and fractional
rounding constant (default value)
= 0.5 (0080h in Q8 format)
High-Resolution Pulse Width Modulator (HRPWM)
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
TMS320x2806x Microcontrollers
389
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Содержание TMS320 2806 Series
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