Texas Instruments TMS320F28069 - 6.9.12 High-Resolution Capture Modules (HRCAP1-HRCAP4)

PIE
HRCAPx
SYSCLK2
PLL2CLK
HRCAPxENCLK
HRCAPxINTn
HRCAP Calibration Logic
EPWMxAEPWMx HRPWM
HRCAP Calibration Signal (Internal)
GPIO
Mux
HRCAPx
Module
136
TMS320F28069 , TMS320F28068 , TMS320F28067 , TMS320F28066
TMS320F28065, TMS320F28064, TMS320F28063, TMS320F28062
SPRS698F –NOVEMBER 2010–REVISED MARCH 2016 www.ti.com
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Detailed Description Copyright © 2010–2016, Texas Instruments Incorporated
6.9.12 High-Resolution Capture Modules (HRCAP1–HRCAP4)
The device contains up to four high-resolution capture (HRCAP) modules. The High-Resolution Capture
(HRCAP) module measures the difference between external pulses with a typical resolution of 300 ps.
Uses for the HRCAP include:
• Capactive 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 measurement (sonar) and scanning
The HRCAP module features include:
• 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
• HRCAP calibration software library supplied by TI is used for both calibration and calculating fractional
pulse widths
The HRCAP module includes one capture channel in addition to a high-resolution calibration block, which
connects internally to the last available ePWMxA HRPWM channel when calibrating (that is, if there are
eight ePWMs with HRPWM capability, it will be HRPWM8A).
Each HRCAP channel has the following independent key resources:
• Dedicated input capture pin
• 16-bit HRCAP clock which is either equal to the PLL2 output frequency (asynchronous to SYSCLK2) or
equal to the SYSCLK2 frequency (synchronous to SYSCLK2)
• High-resolution pulse width capture in a 2-deep buffer
Figure 6-52. HRCAP Functional Block Diagram