TMS320C6747 Datasheet, PDF (142/203 Pages) Texas Instruments – Floating-point Digital Signal Processor

TMS320C6745/6747 Floating-point Digital Signal Processor
SPRS377B – SEPTEMBER 2008 – REVISED DECEMBER 2008
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6.17 Enhanced Capture (eCAP) Peripheral
The C6745/6747 device contains up to three enhanced capture (eCAP) modules. Figure 6-43 shows a
functional block diagram of a module. See the TMS320C6745/C6747 DSP Peripherals Overview
Reference Guide. – Literature Number SPRUFK9 for more details.
Uses for ECAP include:
• Speed measurements of rotating machinery (e.g. toothed sprockets sensed via Hall sensors)
• Elapsed time measurements between position sensor triggers
• Period and duty cycle measurements of Pulse train signals
• Decoding current or voltage amplitude derived from cuty cycle encoded current/voltage sensors
The ECAP module described in this specification includes the following features:
• 32 bit time base
• 4 event time-stamp registers (each 32 bits)
• Edge polarity selection for up to 4 sequenced time-stamp capture events
• Interrupt on either of the 4 events
• Single shot capture of up to 4 event time-stamps
• Continuous mode capture of time-stamps in a 4 deep circular buffer
• Absolute time-stamp capture
• Difference mode time-stamp capture
• All the above resources are dedicated to a single input pin
The eCAP modules are clocked at the SYSCLK2 rate.
The clock enable bits (ECAP1/2/3/4ENCLK) in the PCLKCR1 register are used to turn off the eCAP
modules individually (for low power operation). Upon reset, ECAP1ENCLK, ECAP2ENCLK,
ECAP3ENCLK, and ECAP4EN CLK are set to low, indicating that the peripheral clock is off.
142 Peripheral Information and Electrical Specifications
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