PXD20RM Datasheet, PDF (72/1628 Pages) Freescale Semiconductor, Inc – PXD20 Microcontroller

1.5.29 System timer module (STM)
The STM is a 32-bit timer designed to support commonly required system and application software timing
functions. The STM includes a 32-bit up counter and four 32-bit compare channels with a separate
interrupt source for each channel. The counter is driven by the system clock divided by an 8-bit prescale
value (1 to 256).
• One 32-bit up counter with 8-bit prescaler
• Four 32-bit compare channels
• Independent interrupt source for each channel
• Counter can be stopped in debug mode
1.5.30 Software watchdog timer (SWT)
The SWT features the following:
• Watchdog supporting software activation or enabled out of Reset
• Supports normal or windowed mode
• Watchdog timer value writable once after reset
• Watchdog supports optional halting during low power modes
• Configurable response on timeout: reset, interrupt, or interrupt followed by reset
• Clock source: 128 kHz RC oscillator
1.5.31 Stepper motor controller (SMC)
The SMC module is a PWM motor controller suitable to drive instruments in a cluster configuration or any
other loads requiring a PWM signal. The motor controller has twelve PWM channels associated with two
pins each (24 pins in total) driving up to 6 stepper motors.
The SMC module includes the following features:
• 10/11-bit PWM counter
• 11-bit resolution with selectable PWM dithering function
• Left, right, or center aligned PWM
• Output slew rate control
• Output Short Circuit Detection
This module is suited for, but not limited to, driving small stepper and air core motors used in
instrumentation applications. This module can be used for other motor control or PWM applications that
match the frequency, resolution, and output drive capabilities of the module.
1.5.32 Stepper stall detect (SSD) module
The SSD module provides a circuit to measure and integrate the induced voltage on the non-driven coil of
a stepper motor using full steps when the gauge pointer is returning to zero (RTZ).
The SSD module features the following:
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PXD20 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
Freescale Semiconductor