SMJ320F240 Datasheet, PDF (40/99 Pages) Texas Instruments – DSP CONTROLLER

SMJ320F240
DSP CONTROLLER
SGUS029 – APRIL 1999
full compare units
There are three full compare units on SMJ320F240. These compare units use GP timer1 as the timebase and
generate six outputs for compare and PWM-waveform generation using programmable deadband circuit. The
state of each of the six outputs is configured independently. The compare registers of the compare units are
double-buffered, allowing programmable change of the compare/PWM pulse widths as needed.
programmable-deadband generator
The deadband generator circuit includes three 8-bit counters and an 8-bit compare register. Desired deadband
value (from 0 to 102 ms) can be programmed into the compare register for the outputs of the three compare units.
The deadband generation can be enabled/disabled for each compare unit output individually. The
deadband-generator circuit produces two outputs (with or without deadband zone) for each compare unit output
signal. The output states of the deadband generator are configurable and changeable as needed by way of the
double-buffered ACTR register.
simple compares
SMJ320F240 is equipped with three simple compares that can be used to generate three additional
independent compare or high-precision PWM waveforms. GP timer1 or 2 can be selected as the timebase for
the three simple compares. The states of the outputs of the three simple compares are configurable as
low-active, high-active, forced-low, or forced-high independently. Simple compare registers are
double-buffered, allowing programmable change of the compare/PWM pulse widths as needed. The state of
the simple-compare outputs is configurable and changeable as needed by way of the double-buffered SACTR
register.
compare/PWM waveform generation
Up to 12 compare and/or PWM waveforms (outputs) can be generated simultaneously by SMJ320F240: three
independent pairs (six outputs) by the three full compare units with programmable deadbands, three
independent compares or PWMs (three outputs) by the simple compares, and three independent compare and
PWMs (three outputs) by the GP-timer compares.
compare/PWMs characteristics
Characteristics of the compare / PWMs are as follow:
D 16-bit, 50-ns resolutions
D Programmable deadband for the PWM output pairs, from 0 to 102 ms
D Minimum deadband width of 50 ns
D Change of the PWM carrier frequency for PWM frequency wobbling as needed
D Change of the PWM pulse widths within and after each PWM period as needed
D External maskable power and drive-protection interrupts
D Pulse-pattern-generator circuit, for programmable generation of asymmetric, symmetric, and four-space
vector PWM waveforms
D Minimized CPU overhead using auto-reload of the compare and period registers
capture unit
The capture unit provides a logging function for different events or transitions. The values of the GP timer 2
counter and/or GP timer 3 counter are captured and stored in the two-level first-in first-out (FIFO) stacks when
selected transitions are detected on capture input pins, CAPx for x = 1, 2, 3, or 4. The capture unit of the
SMJ320F240 consists of four capture circuits.
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