6.1 Introduction
6.1.1 Features
The features of the eCAP module include:
• Speed measurements of rotating machinery (for example, toothed sprockets sensed by way of Hall sensors)
• Elapsed time measurements between position sensor pulses
• Period and duty cycle measurements of pulse train signals
• Decoding current or voltage amplitude derived from duty cycle encoded current/voltage sensors
The eCAP module features described in this chapter include:
• 4-event time-stamp registers (each 32 bits)
• Edge polarity selection for up to four sequenced time-stamp capture events
• Interrupt on either of the four events
• Single-shot capture of up to four event time-stamps
• Continuous mode capture of time stamps in a four-deep circular buffer
• Absolute time-stamp capture
• Difference (Delta) mode time-stamp capture
• All above resources are dedicated to a single input pin
• When not used in capture mode, the eCAP module can be configured as a single-channel PWM output
6.1.2 ECAP Related Collateral
Getting Started Materials
•
Leveraging High Resolution Capture (HRCAP) for Single Wire Data Transfer Application Report
6.2 Description
The eCAP module represents one complete capture channel that can be instantiated multiple times, depending
on the target device. In the context of this guide, one eCAP channel has the following independent key
resources:
• Dedicated input capture pin
• 32-bit time base (counter)
• 4 x 32-bit time-stamp capture registers (CAP1-CAP4)
• Four-stage sequencer (modulo4 counter) that is synchronized to external events, eCAP pin rising/falling
edges.
• Independent edge polarity (rising/falling edge) selection for all four events
• Input capture signal prescaling (from 2-62 or bypass)
• One-shot compare register (two bits) to freeze captures after 1-4 time-stamp events
• Control for continuous time-stamp captures using a four-deep circular buffer (CAP1-CAP4) scheme
• Interrupt capabilities on any of the four capture events
Multiple identical eCAP modules can be contained in a system as shown in
is device-dependent and is based on target application needs.
Enhanced Capture (eCAP)
430
TMS320x2806x Microcontrollers
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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