Features

PXS20 Product Brief, Rev. 1

Freescale Semiconductor

21

2.5.29

Serial Peripheral Interface (SPI)

The SPI modules provide a synchronous serial interface for communication between the PXS20 and

external devices.

A SPI module provides these features:

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Full duplex, synchronous transfers

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Master or slave operation

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Programmable master bit rates

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Programmable clock polarity and phase

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End-of-transmission interrupt flag

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Programmable transfer baud rate

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Programmable data frames from 4 to 16 bits

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As many as 8 chip select lines available, depending on package and pin multiplexing

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4 clock and transfer attributes registers

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Chip select strobe available as alternate function on one of the chip select pins for de-glitching

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FIFOs for buffering as many as 5 transfers on the transmit and receive side

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Queueing operation possible through use of the eDMA

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General purpose I/O functionality on pins when not used for SPI

2.5.30

Pulse Width Modulator (PWM)

The PWM module contains four PWM channels, each of which is configured to control a single

half-bridge power stage. Two modules are included on 257 MAPBGA devices; on the 144 LQFP package,

only one module is present. Additionally, four fault input channels are provided per PWM module.

This PWM is capable of controlling most motor types, including:

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AC induction motors (ACIM)

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Permanent Magnet AC motors (PMAC)

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Brushless (BLDC) and brush DC motors (BDC)

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Switched (SRM) and variable reluctance motors (VRM)

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Stepper motors

A PWM module implements the following features:

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16 bits of resolution for center, edge aligned, and asymmetrical PWMs

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Maximum operating frequency as high as 120 MHz

— Clock source not modulated and independent from system clock (generated via secondary

FMPLL)

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Fine granularity control for enhanced resolution of the PWM period

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PWM outputs can operate as complementary pairs or independent channels

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Ability to accept signed numbers for PWM generation