Oscillator Management

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(), main(), 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(), main(), 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.

Referenced by main().

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(), main(), 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(), main(), pll_enable_source(), and sysclk_init().