Specifications

Operational Description of HRPWM

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While using HRPWM feature with no SFO diagnostics, HRPWM logic will not be active for the first 3

TBCLK cycles of the PWM period. While running the application in this configuration, if CMPA register

value is less than 3 cycles, then its CMPAHR register must be cleared to zero. This would avoid any

unexpected transitions on PWM signal.

However, if SFO diagnostic function SFO_MepEn is used in the background, then HRPWM logic will not

be active for the first 6 TBCLK cycles of PWM period. While using SFO_MepEn function if CMPA register

value is less than 6 cycles, then its CMPAHR register must be cleared to zero. This would avoid any

unexpected transitions on PWM signal. Also note that the SFO_MepDis function cannot be used

concurrently with PWM signals with HRPWM enabled (see the previous section for details).

2.4.1 Software Usage

Software library functions SFO_MepEn(int n) and SFO_MepDis(int n) calculate the MEP scale factor for

ePWMn modules, where n = 1, 2, 3, or 4. The scale factor is an integer value in the range 1 – 255, and

represents the number of micro step edge positions available for a system clock period. The scale factor

value is returned in an array of integer variables of length 5 called MEP_ScaleFactor[5]. For example, see

Table 7.

High-Resolution Pulse Width Modulator (HRPWM) SPRU924F– April 2005– Revised October 2011

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