5.1 Introduction
Uses for the HRCAP include:
• Capacitive touch applications
• High-resolution period and duty-cycle measurements of pulse-train cycles
• Instantaneous speed measurements
• Instantaneous frequency measurements
• Voltage measurements across an isolation boundary
• Distance and sonar measurement and scanning
5.1.1 Features
The HRCAP module includes the following features:
• Pulse-width capture in either non-high-resolution or high-resolution modes
• Difference (Delta) mode pulse-width capture
• Typical high-resolution capture on the order of 300 ps resolution on each edge
• Interrupt on either falling or rising edge
• Continuous mode capture of pulse widths in 2-deep buffer
• Calibration logic for precision high-resolution capture
• All of the above resources are dedicated to a single input pin.
5.1.2 HRCAP Related Collateral
Getting Started Materials
•
Leveraging High Resolution Capture (HRCAP) for Single Wire Data Transfer Application Report
5.2 Description
The HRCAP module includes one capture channel in addition to a high-resolution calibration block, which
connects internally to an HRPWM channel during calibration. See the device-specific data manual to determine
which HRPWM channel output the HRCAP module is internally tied to during calibration.
Each HRCAP channel has the following independent key resources:
• Dedicated input capture pin
• 16-bit HRCAP clock (HCCAPCLK) that is either equal to the PLL2 output frequency (asynchronous to
SYSCLK2) or equal to the SYSCLKOUT frequency .
• High-resolution pulse width capture in a two-deep buffer
• High-resolution calibration logic utilizing an internal connection to an HRPWM output
HRCAP Calibration Logic
HRCAPxENCLK
SYSCLKOUT
PLL2CK
HRCAPx
Module
HRCAPxINTn
PIE
EPWMx
HRCAP Calibration Signal (internal)
EPWMxA
(A)
HRPWM
GPIO
Mux
HRCAPx
A.
In general, the largest numerical instance of an HRPWM module channel A output is the internal HRCAP calibration signal input. For
instance, on devices where there are eight HRPWM instances, ePWM8A HRPWM output is the internal HRCAP calibration signal input.
Figure 5-1. HRCAP Module System Block Diagram
High-Resolution Capture (HRCAP) Module
406
TMS320x2806x Microcontrollers
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
Copyright © 2022 Texas Instruments Incorporated
Содержание TMS320 2806 Series
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