Chapter 15 Pulse-Width Modulation Subsystem (PWMSS).

Pulse-Width Modulation Subsystem (PWMSS) www.ti.com
15.1 Pulse-Width Modulation Subsystem (PWMSS)
15.1.1 Introduction
15.1.1.1 Features
The general features of the PWMSS are:
eHRPWM
• Dedicated 16 bit time-base with Period / Frequency control
• Can support 2 independent PWM outputs with Single edge operation
• Can support 2 independent PWM outputs with Dual edge symmetric operation
• Can support 1 independent PWM output with Dual edge asymmetric operation
• Supports Dead-band generation with independent Rising and Falling edge delay control
• Provides asynchronous over-ride control of PWM signals during fault conditions
• Supports “trip zone” allocation of both latched and un-latched fault conditions
• Allows events to trigger both CPU interrupts and start of ADC conversions
• Support PWM chopping by high frequency carrier signal, used for pulse transformer gate drives.
• High-resolution module with programmable delay line.
eCAP
– Programmable on a per PWM period basis.
– Can be inserted either on the rising edge or falling edge of the PWM pulse or both or not at all.
• Dedicated input Capture pin
• 32 bit Time Base (counter)
• 4 x 32 bit Time-stamp Capture registers (CAP1-CAP4)
• 4 stage sequencer (Mod4 counter) which is synchronized to external events (ECAPx pin edges)
• Independent Edge polarity (Rising / Falling edge) selection for all 4 events
• Input Capture signal pre-scaling (from 1 to 16)
• One-shot compare register (2 bits) to freeze captures after 1 to 4 Time-stamp events
• Control for continuous Time-stamp captures using a 4 deep circular buffer (CAP1-CAP4) scheme
• Interrupt capabilities on any of the 4 capture events
eQEP
• Input Synchronization
• Three Stage/Six Stage Digital Noise Filter
• Quadrature Decoder Unit
• Position Counter and Control unit for position measurement
• Quadrature Edge Capture unit for low speed measurement
• Unit Time base for speed/frequency measurement
• Watchdog Timer for detecting stalls
15.1.1.2 UnsupportedFeatures
The PWMSS module features not supported are shown in Table 15-1.
Table 15-1. Unsupported Features
Feature Reason
ePWM inputs Not pinned out
ePWM tripzone 1-5 inputs Only Tripzone0 is pinned out
ePWM digital comparators Inputs not connected
1614Pulse-Width Modulation Subsystem (PWMSS) SPRUH73E–October 2011–Revised May 2012
Submit Documentation Feedback
Copyright © 2011–2012, Texas Instruments Incorporated