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Introduction
31.1.3 LPTMR prescaler/glitch filter clocking options
The prescaler and glitch filter of the LPTMR module can be clocked from one of four
sources determined by LPTMR0_PSR[PCS]. The following table shows the chip-specific
clock assignments for this field.
The chosen clock must remain enabled if the LPTMR is to
continue operating in all required low-power modes.
LPTMR0_PSR[PCS]
00
01
10
11
See
Clock Distribution
31.2 Introduction
The low-power timer (LPTMR) can be configured to operate as a time counter with
optional prescaler, or as a pulse counter with optional glitch filter, across all power
modes, including the low-leakage modes. It can also continue operating through most
system reset events, allowing it to be used as a time of day counter.
31.2.1 Features
The features of the LPTMR module include:
• 16-bit time counter or pulse counter with compare
• Optional interrupt can generate asynchronous wakeup from any low-power mode
• Hardware trigger output
• Counter supports free-running mode or reset on compare
• Configurable clock source for prescaler/glitch filter
• Configurable input source for pulse counter
• Rising-edge or falling-edge
502
NOTE
Prescaler/glitch filter clock
number
0
1
2
3
for more details on these clocks.
KL27 Sub-Family Reference Manual , Rev. 5, 01/2016
Chip clock
MCGIRCLK—internal reference clock
(not available in LLS and VLLS modes)
LPO—1 kHz clock (not available in
VLLS0 mode)
ERCLK32K (not available in VLLS0
mode when using 32 kHz oscillator)
OSCERCLK—external reference clock
(not available in VLLS0 mode)
Freescale Semiconductor, Inc.
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