ePWM
7 - 36 C2000 Microcontroller Workshop - Control Peripherals
Hi-Resolution PWM (HRPWM)
Hi-Resolution PWM (HRPWM)
Significantly increases the resolution of conventionally derived digital PWM
Uses 8-bit extensions to Compare registers (CMPxHR), Period register
(TBPRDHR) and Phase register (TBPHSHR) for edge positioning control
Typically used when PWM resolution falls below ~9-10 bits which occurs at
frequencies greater than ~180 kHz (with system clock of 90 MHz)
Not all ePWM outputs support HRPWM feature (see device datasheet)
PWM Period
Device Clock
(i.e. 90 MHz)
Regular
PWM Step
(i.e. 11.1 ns)
HRPWM
Micro Step (~150 ps)
HRPWM divides a clock
cycle into smaller steps
called Micro Steps
(Step Size ~= 150 ps)
ms ms ms
ms ms ms
Calibration Logic
Calibration Logic tracks the
number of Micro Steps per
clock to account for
variations caused by
Temp/Volt/Process
The high-resolution PWM feature significantly increases the resolution of conventionally-derived
PWM. High-resolution PWM divides a clock cycle into smaller steps called micro steps. The
step size is approximately 150 picoseconds. This is typically used when PWM resolution falls
below approximately 9 or 10 bits, which occurs at frequencies greater than approximately 180
kHz with a system clock of 90 MHz.
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