TMS320F28069_14 Datasheet, PDF (133/175 Pages) Texas Instruments – Piccolo Microcontrollers

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TMS320F28069, TMS320F28068, TMS320F28067, TMS320F28066
TMS320F28065, TMS320F28064, TMS320F28063, TMS320F28062
SPRS698D – NOVEMBER 2010 – REVISED DECEMBER 2012
5.18 High-Resolution PWM (HRPWM)
This module combines multiple delay lines in a single module and a simplified calibration system by using
a dedicated calibration delay line. For each ePWM module there is one HR delay line.
The HRPWM module offers PWM resolution (time granularity) that is significantly better than what can be
achieved using conventionally derived digital PWM methods. The key points for the HRPWM module are:
• Significantly extends the time resolution capabilities of conventionally derived digital PWM
• This capability can be utilized in both single edge (duty cycle and phase-shift control) as well as dual
edge control for frequency/period modulation.
• Finer time granularity control or edge positioning is controlled via extensions to the Compare A and
Phase registers of the ePWM module.
• HRPWM capabilities, when available on a particular device, are offered only on the A signal path of an
ePWM module (that is, on the EPWMxA output). EPWMxB output has conventional PWM capabilities.
NOTE
The minimum SYSCLKOUT frequency allowed for HRPWM is 60 MHz.
NOTE
When dual-edge high-resolution is enabled (high-resolution period mode), the PWMxB
channel will have ±1–2 TBCLK cycles of jitter on the output.
5.18.1 High-Resolution PWM (HRPWM) Electrical Data/Timing
Table 5-55 shows the high-resolution PWM switching characteristics.
Table 5-55. High-Resolution PWM Characteristics⁽¹⁾
PARAMETER
Micro Edge Positioning (MEP) step size⁽²⁾
MIN TYP MAX UNIT
150 310 ps
(1) The HRPWM operates at a minimum SYSCLKOUT frequency of 60 MHz.
(2) Maximum MEP step size is based on worst-case process, maximum temperature and maximum voltage. MEP step size will increase
with low voltage and high temperature and decrease with voltage and cold temperature.
Applications that use the HRPWM feature should use MEP Scale Factor Optimizer (SFO) estimation software functions. See the TI
software libraries for details of using SFO function in end applications. SFO functions help to estimate the number of MEP steps per
SYSCLKOUT period dynamically while the HRPWM is in operation.
Copyright © 2010–2012, Texas Instruments Incorporated
Peripheral and Electrical Specifications 133
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