PXD20 Datasheet, PDF (21/130 Pages) Freescale Semiconductor, Inc – PXD20 Microcontroller

Overview
1.4.28 Real time counter (RTC)
The Real Timer Counter supports wake-up from Low Power modes or Real Time Clock generation
• Configurable resolution for different timeout periods
— 1 s resolution for >1 hour period
— 1 ms resolution for 2 second period
• Selectable clock sources from external 32 KHz crystal, external 4–16 MHz crystal, internal 128 kHz RC oscillator or
divided internal 16 MHz RC oscillator
1.4.29 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
1.4.30 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
1.4.31 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.
PXD20 Microcontroller Data Sheet, Rev. 2
Freescale Semiconductor
Preliminary—Subject to Change Without Notice
21