Overview
788
SPNU503C – March 2018
Copyright © 2018, Texas Instruments Incorporated
High-End Timer (N2HET) Module
20.1 Overview
The N2HET is a fifth-generation Texas Instruments (TI) advanced intelligent timer module. It provides an
enhanced feature set compared to previous generations.
This timer module provides sophisticated timing functions for real-time applications such as engine
management or motor control. The high resolution hardware channels allow greater accuracy for widely
used timing functions such as period and pulse measurements, output compare, and PWMs.
The reduced instruction set, based mostly on very simple, but comprehensive instructions, improves the
definition and development cycle time of an application and its derivatives. The N2HET breakpoint feature,
combined with various stop capabilities, makes the N2HET software application easy to debug.
20.1.1 Features
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Programmable timer for input and output timing functions
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Reduced instruction set (30 instructions) for dedicated time and angle functions
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Up to maximum of 128 96-bit words of instruction RAM protected by parity. Check your datasheet for
the actual number of words implemented.
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User defined configuration of 25-bit virtual counters for timer, event counters and angle counters
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7-bit hardware counters for each pin allow up to 32-bit resolution in conjunction with the 25-bit virtual
counters
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Up to 32 pins usable for input signal measurements or output signal generation
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Programmable suppression filter for each input pin with adjustable suppression window
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Low CPU overhead and interrupt load
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Efficient data transfer to or from the CPU memory with dedicated High-End-Timer Transfer Unit (HTU)
or DMA
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Diagnostic capabilities with different loopback mechanisms and pin status readback functionality
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Hardware Angle Generator (HWAG)
20.1.2 Major Advantages
In addition to classic time functions such as input capture or multiple PWMs, higher-level time functions
can be easily implemented in the timer program main loop. Higher-level time functions include angle
driven wave forms, angle- and time-driven pulses, and input pulse width modulation (PWM) duty cycle
measurement.
Because of these high-level functions, data exchanges with the CPU are limited to the fundamental
parameters of the application (periods, pulse widths, angle values, etc.); and the real-time constraints for
parameter communication are dramatically minimized; for example, few interrupts are required and
asynchronous parameter updates are allowed.
The reduced instruction set and simple execution flow control make it simple and easy to develop and
modify programs. Simple algorithms can embed the entire flow control inside the N2HET program itself.
More complex algorithms can take advantage of the CPU access to the N2HET RAM. With this, the CPU
program can make calculations and can modify the timer program flow by changing the data and control
fields of the N2HET RAM. CPU access to the N2HET RAM also improves the debug and development of
timer programs. The CPU program can stop the N2HET and view the contents of the program, control,
and data fields that reside in the N2HET RAM.
Finally, the modular structure provides maximum flexibility to address a wide range of applications. The
timer resolution can be selected from two cascaded prescalers to adjust the loop resolution and HR
clocks. The 32 I/O pins can provide any combination of input, period or pulse capture, and output
compare, including high resolution for each channel.
