Datasheet

If booting from ROM, the device executes in boot loader mode or proceeds with a

secondary boot to a QSPI device connected to QSPI0.

2.1.6 Clock options

This chip provides a wide range of sources to generate the internal clocks. These

sources include internal resistor capacitor (IRC) oscillators, external oscillators,

external clock sources, ceramic resonators, phase-locked loop (PLL) and frequency-

locked loop (FLL). These sources can be configured to provide the required

performance and optimize the power consumption.

The IRC oscillators include the 48 MHz internal resister capacitor (IRC48M)

oscillator, the 4 MHz internal resister capacitor (4 MHz IRC) oscillator, the 32 kHz

internal resister capacitor (32 kHz IRC) oscillator, and the low power oscillator

(LPO).

The 48 MHz internal resister capacitor (IRC48M) oscillator generates a 48 MHz clock

and synchronizes with the USB clock in full speed mode to achieve the required

accuracy.

The 4 MHz internal resister capacitor (4 MHz IRC) oscillator generates a 4 MHz

clock. It can serve as the low power, low speed system clock under very low power

run (VLPR) mode or very low power wait (VLPW) mode. It can also be provided as

clock source for other on-chip modules. The 4 MHz IRC cannot be used in any VLLS

modes.

The 32 kHz internal resister capacitor (32 kHz IRC) oscillator generates a 32 kHz

clock. It can be used as FLL internal reference clock or can be provided as low power

clock source to other on-chip modules. The 32 kHz IRC cannot be used in any VLLS

modes.

The LPO generates a 1 kHz clock and cannot be used in VLLS0 mode.

The system oscillator supports low frequency crystals (32 kHz to 40 kHz), high

frequency crystals (1 MHz to 32 MHz), and ceramic resonators (1 MHz to 32 MHz).

An external clock source, DC to 48 MHz, can be used as the system clock through the

EXTAL0 pin. The external oscillator also supports a low speed external clock (32.768

kHz) on the RTC_CLKIN pin for use with the RTC.

The frequency-locked loop (FLL) can generate clock up to four programmable

different frequency ranges (20–25 MHz, 40–50 MHz, 60–75 MHz or 80–100 MHz)

with low speed (31.25–39.0625 kHz) internal or external reference clock. The FLL

can be used as the system clock or clock source for other on-chip modules.

Overview

Kinetis KL82 Microcontroller, Rev. 3, 08/2016

NXP Semiconductors