PIC16LF1904 Datasheet, PDF (57/288 Pages) Microchip Technology – 28/40/44-Pin Flash-Based, 8-Bit CMOS Microcontrollers with LCD Driver and nanoWatt XLP Technology

6.0 OSCILLATOR MODULE
6.1 Overview
The oscillator module has a wide variety of clock
sources and selection features that allow it to be used
in a wide range of applications while maximizing perfor-
mance and minimizing power consumption. Figure 6-1
illustrates a block diagram of the oscillator module.
Clock sources can be supplied from external clock
circuits. In addition, the system clock source can be
supplied from one of two internal oscillators, with a
choice of speeds selectable via software. Additional
clock features include:
• Selectable system clock source between external
or internal sources via software.
• Fast start-up oscillator allows internal circuits to
power up and stabilize before switching to the 16
MHz HFINTOSC
The oscillator module can be configured in one of the
following clock modes:
1. ECL – External Clock Low-Power mode
(0 MHz to 0.5 MHz)
2. ECM – External Clock Medium-Power mode
(0.5 MHz to 4 MHz)
3. ECH – External Clock High-Power mode
(4 MHz to 20 MHz)
4. INTOSC – Internal oscillator (31 kHz to 16 MHz).
Clock Source modes are selected by the FOSC<1:0>
bits in the Configuration Word 1. The FOSC bits
determine the type of oscillator that will be used when
the device is first powered.
The EC clock mode relies on an external logic level
signal as the device clock source.
The INTOSC internal oscillator block produces a low
and high-frequency clock source, designated
LFINTOSC and HFINTOSC (see Internal Oscillator
Block, Figure 6-1). A wide selection of device clock
frequencies may be derived from these two clock
sources.
PIC16LF1904/6/7
 2011 Microchip Technology Inc.
Preliminary
DS41569A-page 57