Microchip® Advanced Software Framework

Home
Features

Documentation

ASF Architecture

Reference Manual

All Data Structures Files Functions Variables Typedefs Enumerations Enumerator Macros Groups Pages

This group contains functions and definitions related to configuring and enabling/disabling on-chip oscillators.

Internal RC-oscillators, external crystal oscillators and external clock generators are supported by this module. What all of these have in common is that they swing at a fixed, nominal frequency which is normally not adjustable.

Example: Enabling an oscillator

The following example demonstrates how to enable the external oscillator on XMEGA A and wait for it to be ready to use. The oscillator identifiers are platform-specific, so while the same procedure is used on all platforms, the parameter to osc_enable() will be different from device to device.

osc_enable(OSC_ID_XOSC);

osc_wait_ready(OSC_ID_XOSC);

Board-specific Definitions

If external oscillators are used, the board code must provide the following definitions for each of those:

BOARD_<osc name>_HZ: The nominal frequency of the oscillator.
BOARD_<osc name>_STARTUP_US: The startup time of the oscillator in microseconds.
BOARD_<osc name>_TYPE: The type of oscillator connected, i.e. whether it's a crystal or external clock, and sometimes what kind of crystal it is. The meaning of this value is platform-specific.

Functions
static void	osc_disable (uint32_t ul_id)

static void	osc_enable (uint32_t ul_id)

static uint32_t	osc_get_rate (uint32_t ul_id)

static bool	osc_is_ready (uint32_t ul_id)

Oscillator Management
static void	osc_wait_ready (uint8_t id)
	Wait until the oscillator identified by id is ready. More...

Oscillator identifiers
#define	OSC_SLCK_32K_RC 0
	Internal 32kHz RC oscillator. More...

#define	OSC_SLCK_32K_XTAL 1
	External 32kHz crystal oscillator. More...

#define	OSC_SLCK_32K_BYPASS 2
	External 32kHz bypass oscillator. More...

#define	OSC_MAINCK_4M_RC 3
	Internal 4MHz RC oscillator. More...

#define	OSC_MAINCK_8M_RC 4
	Internal 8MHz RC oscillator. More...

#define	OSC_MAINCK_12M_RC 5
	Internal 12MHz RC oscillator. More...

#define	OSC_MAINCK_XTAL 6
	External crystal oscillator. More...

#define	OSC_MAINCK_BYPASS 7
	External bypass oscillator. More...

Oscillator clock speed in hertz
#define	OSC_SLCK_32K_RC_HZ CHIP_FREQ_SLCK_RC
	Internal 32kHz RC oscillator. More...

#define	OSC_SLCK_32K_XTAL_HZ BOARD_FREQ_SLCK_XTAL
	External 32kHz crystal oscillator. More...

#define	OSC_SLCK_32K_BYPASS_HZ BOARD_FREQ_SLCK_BYPASS
	External 32kHz bypass oscillator. More...

#define	OSC_MAINCK_4M_RC_HZ CHIP_FREQ_MAINCK_RC_4MHZ
	Internal 4MHz RC oscillator. More...

#define	OSC_MAINCK_8M_RC_HZ CHIP_FREQ_MAINCK_RC_8MHZ
	Internal 8MHz RC oscillator. More...

#define	OSC_MAINCK_12M_RC_HZ CHIP_FREQ_MAINCK_RC_12MHZ
	Internal 12MHz RC oscillator. More...

#define	OSC_MAINCK_XTAL_HZ BOARD_FREQ_MAINCK_XTAL
	External crystal oscillator. More...

#define	OSC_MAINCK_BYPASS_HZ BOARD_FREQ_MAINCK_BYPASS
	External bypass oscillator. More...

#define OSC_MAINCK_12M_RC 5

Internal 12MHz RC oscillator.

Referenced by genclk_enable_source(), osc_disable(), osc_enable(), osc_get_rate(), osc_is_ready(), and sysclk_init().

#define OSC_MAINCK_12M_RC_HZ CHIP_FREQ_MAINCK_RC_12MHZ

Internal 12MHz RC oscillator.

Referenced by genclk_get_frequency_hz(), osc_get_rate(), and sysclk_get_main_hz().

#define OSC_MAINCK_4M_RC 3

Internal 4MHz RC oscillator.

Referenced by genclk_enable_source(), osc_disable(), osc_enable(), osc_get_rate(), and osc_is_ready().

#define OSC_MAINCK_4M_RC_HZ CHIP_FREQ_MAINCK_RC_4MHZ

Internal 4MHz RC oscillator.

Referenced by genclk_get_frequency_hz(), osc_get_rate(), and sysclk_get_main_hz().

#define OSC_MAINCK_8M_RC 4

Internal 8MHz RC oscillator.

Referenced by genclk_enable_source(), osc_disable(), osc_enable(), osc_get_rate(), osc_is_ready(), and sysclk_init().

#define OSC_MAINCK_8M_RC_HZ CHIP_FREQ_MAINCK_RC_8MHZ

Internal 8MHz RC oscillator.

Referenced by genclk_get_frequency_hz(), osc_get_rate(), and sysclk_get_main_hz().

#define OSC_MAINCK_BYPASS 7

External bypass oscillator.

Referenced by genclk_enable_source(), osc_disable(), osc_enable(), osc_get_rate(), osc_is_ready(), and sysclk_init().

#define OSC_MAINCK_BYPASS_HZ BOARD_FREQ_MAINCK_BYPASS

External bypass oscillator.

Referenced by sysclk_get_main_hz().

#define OSC_MAINCK_XTAL 6

External crystal oscillator.

Referenced by genclk_enable_source(), osc_disable(), osc_enable(), osc_get_rate(), osc_is_ready(), and sysclk_init().

#define OSC_MAINCK_XTAL_HZ BOARD_FREQ_MAINCK_XTAL

External crystal oscillator.

Referenced by genclk_get_frequency_hz(), and sysclk_get_main_hz().

#define OSC_SLCK_32K_BYPASS 2

External 32kHz bypass oscillator.

Referenced by genclk_enable_source(), osc_disable(), osc_enable(), osc_get_rate(), osc_is_ready(), and sysclk_init().

#define OSC_SLCK_32K_BYPASS_HZ BOARD_FREQ_SLCK_BYPASS

External 32kHz bypass oscillator.

Referenced by sysclk_get_main_hz().

#define OSC_SLCK_32K_RC 0

Internal 32kHz RC oscillator.

Referenced by genclk_enable_source(), osc_disable(), osc_enable(), osc_get_rate(), osc_is_ready(), and sysclk_init().

#define OSC_SLCK_32K_RC_HZ CHIP_FREQ_SLCK_RC

Internal 32kHz RC oscillator.

Referenced by genclk_get_frequency_hz(), osc_enable(), osc_get_rate(), and sysclk_get_main_hz().

#define OSC_SLCK_32K_XTAL 1

External 32kHz crystal oscillator.

Referenced by genclk_enable_source(), osc_disable(), osc_enable(), osc_get_rate(), osc_is_ready(), and sysclk_init().

#define OSC_SLCK_32K_XTAL_HZ BOARD_FREQ_SLCK_XTAL

External 32kHz crystal oscillator.

Referenced by genclk_get_frequency_hz(), and sysclk_get_main_hz().

static void osc_disable ( uint32_t ul_id )

inlinestatic

References OSC_MAINCK_12M_RC, OSC_MAINCK_4M_RC, OSC_MAINCK_8M_RC, OSC_MAINCK_BYPASS, OSC_MAINCK_XTAL, OSC_SLCK_32K_BYPASS, OSC_SLCK_32K_RC, OSC_SLCK_32K_XTAL, PMC_OSC_BYPASS, pmc_osc_disable_fastrc(), pmc_osc_disable_xtal(), and PMC_OSC_XTAL.

static void osc_enable ( uint32_t ul_id )

inlinestatic

References BOARD_OSC_STARTUP_US, OSC_MAINCK_12M_RC, OSC_MAINCK_4M_RC, OSC_MAINCK_8M_RC, OSC_MAINCK_BYPASS, OSC_MAINCK_XTAL, OSC_SLCK_32K_BYPASS, OSC_SLCK_32K_RC, OSC_SLCK_32K_RC_HZ, OSC_SLCK_32K_XTAL, PMC_OSC_BYPASS, PMC_OSC_XTAL, pmc_switch_mainck_to_fastrc(), pmc_switch_mainck_to_xtal(), pmc_switch_sclk_to_32kxtal(), and pmc_us_to_moscxtst.

Referenced by genclk_enable_source(), pll_enable_source(), and sysclk_init().

static uint32_t osc_get_rate ( uint32_t ul_id )

inlinestatic

References BOARD_FREQ_MAINCK_BYPASS, BOARD_FREQ_MAINCK_XTAL, BOARD_FREQ_SLCK_BYPASS, BOARD_FREQ_SLCK_XTAL, OSC_MAINCK_12M_RC, OSC_MAINCK_12M_RC_HZ, OSC_MAINCK_4M_RC, OSC_MAINCK_4M_RC_HZ, OSC_MAINCK_8M_RC, OSC_MAINCK_8M_RC_HZ, OSC_MAINCK_BYPASS, OSC_MAINCK_XTAL, OSC_SLCK_32K_BYPASS, OSC_SLCK_32K_RC, OSC_SLCK_32K_RC_HZ, and OSC_SLCK_32K_XTAL.

Referenced by pll_config_init().

static bool osc_is_ready ( uint32_t ul_id )

inlinestatic

References OSC_MAINCK_12M_RC, OSC_MAINCK_4M_RC, OSC_MAINCK_8M_RC, OSC_MAINCK_BYPASS, OSC_MAINCK_XTAL, OSC_SLCK_32K_BYPASS, OSC_SLCK_32K_RC, OSC_SLCK_32K_XTAL, pmc_osc_is_ready_32kxtal(), and pmc_osc_is_ready_mainck().

Referenced by genclk_enable_source(), and osc_wait_ready().

static void osc_wait_ready ( uint8_t id )

inlinestatic

Wait until the oscillator identified by id is ready.

This function will busy-wait for the oscillator identified by id to become stable and ready to use as a clock source.

Parameters

id	A number identifying the oscillator to wait for.

References osc_is_ready().

Referenced by genclk_enable_source(), pll_enable_source(), and sysclk_init().