UCD90124RGCT datasheet(21/46 Pages) TI

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UCD90124

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SLVSA29A – NOVEMBER 2009 – REVISED DECEMBER 2009

GPI Special Functions

Figure 14 lists and describes five special input functions for which GPIs can be used. There can be no more than

one pin assigned to each of these functions.

Figure 14. GPI Configuration – Special Input Functions

PWM Outputs

Pins 17–24 can be configured as fast pulse-width modulators (FPWMs). The frequency range is 15.259 kHz to

125 MHz. FPWMs can be configured as closed-loop margining outputs or general-purpose PWMs.

Any FPWM pin not used as a PWM output can be configured as a GPIO. One FPWM in a pair can be used as a

PWM output and the other pin can be used as a GPO. The FPWM pins are actively driven low from reset when

used as GPOs.

The frequency settings for the FPWMs apply to pairs of pins:

•

FPWM1 and FPWM2 – same frequency

•

FPWM3 and FPWM4 – same frequency

•

FPWM5 and FPWM6 – same frequency

•

FPWM7 and FPWM8 – same frequency

If an FPWM pin from a pair is not used while its companion is set up to function, it is recommended to configure

the unused FPWM pin as an active-low open-drain GPO so that it does not disturb the rest of the system. By

setting an FPWM, it automatically enables the other FPWM within the pair if it was not configured for any other

functionality.

Pins 31, 32, 41, and 42 can be used as GPIs or PWM outputs.

If configured as PWM outputs, then limitations apply:

•

PWM1 has a fixed frequency of 10 kHz

•

PWM2 has a fixed frequency of 1 kHz

•

PWM3 and PWM4 frequencies can be 0.93 Hz to 7.8125 MHz.

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UCD90124RGCT Datasheet(PDF) 21 Page - Texas Instruments