Atmel Software Framework

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:

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_8M_RC   3
 Internal 8MHz RC oscillator. More...
 
#define OSC_MAINCK_16M_RC   4
 Internal 16MHz RC oscillator. More...
 
#define OSC_MAINCK_24M_RC   5
 Internal 24MHz 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_8M_RC_HZ   CHIP_FREQ_MAINCK_RC_8MHZ
 Internal 8MHz RC oscillator. More...
 
#define OSC_MAINCK_16M_RC_HZ   CHIP_FREQ_MAINCK_RC_16MHZ
 Internal 16MHz RC oscillator. More...
 
#define OSC_MAINCK_24M_RC_HZ   CHIP_FREQ_MAINCK_RC_24MHZ
 Internal 24MHz 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_16M_RC   4

Internal 16MHz RC oscillator.

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

#define OSC_MAINCK_16M_RC_HZ   CHIP_FREQ_MAINCK_RC_16MHZ

Internal 16MHz RC oscillator.

Referenced by osc_get_rate(), and sysclk_get_main_hz().

#define OSC_MAINCK_24M_RC   5

Internal 24MHz RC oscillator.

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

#define OSC_MAINCK_24M_RC_HZ   CHIP_FREQ_MAINCK_RC_24MHZ

Internal 24MHz RC oscillator.

Referenced by osc_get_rate(), and sysclk_get_main_hz().

#define OSC_MAINCK_8M_RC   3

Internal 8MHz RC oscillator.

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

#define OSC_MAINCK_8M_RC_HZ   CHIP_FREQ_MAINCK_RC_8MHZ

Internal 8MHz RC oscillator.

Referenced by 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 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 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 sysclk_get_main_hz().

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
idA number identifying the oscillator to wait for.

References osc_is_ready().

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