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.

Macros
#define	CONFIG_RCFAST_FRANGE 0

#define	OSC0_GAIN_VALUE SCIF_OSCCTRL0_GAIN(3)

#define	OSC0_MODE_VALUE OSC_MODE_XTAL
	Board-dependent value written to the MODE bitfield of PM_OSCCTRL(0) More...

#define	OSC0_STARTUP_TIMEOUT 2560
	Number of slow clock cycles to wait for OSC0 to start. More...

#define	OSC0_STARTUP_VALUE OSC_STARTUP_2048
	Board-dependent value written to the STARTUP bitfield of PM_OSCCTRL(0) More...

#define	OSC32_MODE_VALUE OSC32_MODE_XTAL

#define	OSC32_STARTUP_VALUE OSC32_STARTUP_131072

Functions
void	osc_priv_disable_osc0 (void)

void	osc_priv_disable_osc32 (void)

void	osc_priv_disable_rc1m (void)

void	osc_priv_disable_rc32k (void)

void	osc_priv_disable_rc80m (void)

void	osc_priv_disable_rcfast (void)

void	osc_priv_enable_osc0 (void)

void	osc_priv_enable_osc32 (void)

void	osc_priv_enable_rc1m (void)

void	osc_priv_enable_rc32k (void)

void	osc_priv_enable_rc80m (void)

void	osc_priv_enable_rcfast (void)

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

static void	osc_enable (uint8_t id)
	Enable oscillator id. More...

static void	osc_disable (uint8_t id)
	Disable oscillator id. More...

static bool	osc_is_ready (uint8_t id)
	Determine whether oscillator id is ready. More...

static uint32_t	osc_get_rate (uint8_t id)
	Return the frequency of oscillator id in Hz. More...

Oscillator identifiers
#define	OSC_ID_OSC0 0
	External Oscillator 0. More...

#define	OSC_ID_OSC32 1
	External 32 kHz oscillator. More...

#define	OSC_ID_RC32K 2
	Internal 32 kHz RC oscillator. More...

#define	OSC_ID_RC80M 3
	Internal 80 MHz RC oscillator. More...

#define	OSC_ID_RCFAST 4
	Internal 4-8-12 MHz RCFAST oscillator. More...

#define	OSC_ID_RC1M 5
	Internal 1 MHz RC oscillator. More...

#define	OSC_ID_RCSYS 6
	Internal System RC oscillator. More...

OSC0 mode values
#define	OSC_MODE_EXTERNAL 0
	External clock connected to XIN. More...

#define	OSC_MODE_XTAL SCIF_OSCCTRL0_MODE
	Crystal connected to XIN/XOUT. More...

OSC32 mode values
#define	OSC32_MODE_EXTERNAL BSCIF_OSCCTRL32_MODE(0)
	External clock connected to XIN32. More...

#define	OSC32_MODE_XTAL BSCIF_OSCCTRL32_MODE(1)
	Crystal connected to XIN32/XOUT32. More...

#define	OSC32_MODE_XTAL_HC BSCIF_OSCCTRL32_MODE(4)
	Crystal connected to XIN32/XOUT32 in high current mode. More...

OSC0 startup values
#define	OSC_STARTUP_0 SCIF_OSCCTRL0_STARTUP(0)
	0 cycles More...

#define	OSC_STARTUP_64 SCIF_OSCCTRL0_STARTUP(1)
	64 cycles (560 us) More...

#define	OSC_STARTUP_128 SCIF_OSCCTRL0_STARTUP(2)
	128 cycles (1.1 ms) More...

#define	OSC_STARTUP_2048 SCIF_OSCCTRL0_STARTUP(3)
	2048 cycles (18 ms) More...

#define	OSC_STARTUP_4096 SCIF_OSCCTRL0_STARTUP(4)
	4096 cycles (36 ms) More...

#define	OSC_STARTUP_8192 SCIF_OSCCTRL0_STARTUP(5)
	8192 cycles (71 ms) More...

#define	OSC_STARTUP_16384 SCIF_OSCCTRL0_STARTUP(6)
	16384 cycles (143 ms) More...

#define	OSC_STARTUP_32768 SCIF_OSCCTRL0_STARTUP(7)
	32768 cycles (285 ms) More...

OSC32 startup values
#define	OSC32_STARTUP_0 BSCIF_OSCCTRL32_STARTUP(0)
	0 cycles More...

#define	OSC32_STARTUP_128 BSCIF_OSCCTRL32_STARTUP(1)
	128 cycles (1.1 ms) More...

#define	OSC32_STARTUP_8192 BSCIF_OSCCTRL32_STARTUP(2)
	8192 cycles (72.3 ms) More...

#define	OSC32_STARTUP_16384 BSCIF_OSCCTRL32_STARTUP(3)
	16384 cycles (143 ms) More...

#define	OSC32_STARTUP_65536 BSCIF_OSCCTRL32_STARTUP(4)
	65536 cycles (570 ms) More...

#define	OSC32_STARTUP_131072 BSCIF_OSCCTRL32_STARTUP(5)
	131072 cycles (1.1 s) More...

#define	OSC32_STARTUP_262144 BSCIF_OSCCTRL32_STARTUP(6)
	262144 cycles (2.3 s) More...

#define	OSC32_STARTUP_524288 BSCIF_OSCCTRL32_STARTUP(7)
	524288 cycles (4.6 s) More...

RC oscillator frequency limits
The frequency of the internal RC oscillators may drift a bit as a result of temperature changes. These definitions provide upper and lower limits which may be used to calculate upper and lower limits of timeouts, derived clock frequencies, etc.
#define	OSC_RCSYS_NOMINAL_HZ 115000
	Nominal frequency of RCSYS in Hz. More...

#define	OSC_RCSYS_MIN_HZ 100000
	Minimum frequency of RCSYS in Hz. More...

#define	OSC_RCSYS_MAX_HZ 120000
	Maximum frequency of RCSYS in Hz. More...

#define	OSC_RC32K_NOMINAL_HZ 32768
	Nominal frequency of RC32K in Hz. More...

#define	OSC_RC32K_MIN_HZ 20000
	Minimum frequency of RC32K in Hz. More...

#define	OSC_RC32K_MAX_HZ 44000
	Maximum frequency of RC32K in Hz. More...

#define	OSC_RC80M_NOMINAL_HZ 80000000
	Nominal frequency of RC80M in Hz. More...

#define	OSC_RCFAST4M_NOMINAL_HZ 4000000
	Nominal frequency of RCFAST4M in Hz. More...

#define	OSC_RCFAST8M_NOMINAL_HZ 8000000
	Nominal frequency of RCFAST8M in Hz. More...

#define	OSC_RCFAST12M_NOMINAL_HZ 12000000
	Nominal frequency of RCFAST12M in Hz. More...

#define	OSC_RC1M_NOMINAL_HZ 1000000
	Nominal frequency of RC1M in Hz. More...

#define CONFIG_RCFAST_FRANGE 0

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

#define OSC0_GAIN_VALUE SCIF_OSCCTRL0_GAIN(3)

#define OSC0_MODE_VALUE OSC_MODE_XTAL

Board-dependent value written to the MODE bitfield of PM_OSCCTRL(0)

#define OSC0_STARTUP_TIMEOUT 2560

Number of slow clock cycles to wait for OSC0 to start.

This is the number of slow clock cycles corresponding to OSC0_STARTUP_VALUE with an additional 25% safety margin. If the oscillator isn't running when this timeout has expired, it is assumed to have failed to start.

#define OSC0_STARTUP_VALUE OSC_STARTUP_2048

Board-dependent value written to the STARTUP bitfield of PM_OSCCTRL(0)

#define OSC32_MODE_EXTERNAL BSCIF_OSCCTRL32_MODE(0)

External clock connected to XIN32.

#define OSC32_MODE_VALUE OSC32_MODE_XTAL

#define OSC32_MODE_XTAL BSCIF_OSCCTRL32_MODE(1)

Crystal connected to XIN32/XOUT32.

#define OSC32_MODE_XTAL_HC BSCIF_OSCCTRL32_MODE(4)

Crystal connected to XIN32/XOUT32 in high current mode.

#define OSC32_STARTUP_0 BSCIF_OSCCTRL32_STARTUP(0)

0 cycles

#define OSC32_STARTUP_128 BSCIF_OSCCTRL32_STARTUP(1)

128 cycles (1.1 ms)

#define OSC32_STARTUP_131072 BSCIF_OSCCTRL32_STARTUP(5)

131072 cycles (1.1 s)

#define OSC32_STARTUP_16384 BSCIF_OSCCTRL32_STARTUP(3)

16384 cycles (143 ms)

#define OSC32_STARTUP_262144 BSCIF_OSCCTRL32_STARTUP(6)

262144 cycles (2.3 s)

#define OSC32_STARTUP_524288 BSCIF_OSCCTRL32_STARTUP(7)

524288 cycles (4.6 s)

#define OSC32_STARTUP_65536 BSCIF_OSCCTRL32_STARTUP(4)

65536 cycles (570 ms)

#define OSC32_STARTUP_8192 BSCIF_OSCCTRL32_STARTUP(2)

8192 cycles (72.3 ms)

#define OSC32_STARTUP_VALUE OSC32_STARTUP_131072

#define OSC_ID_OSC0 0

External Oscillator 0.

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

#define OSC_ID_OSC32 1

External 32 kHz oscillator.

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

#define OSC_ID_RC1M 5

Internal 1 MHz RC oscillator.

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

#define OSC_ID_RC32K 2

Internal 32 kHz RC oscillator.

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

#define OSC_ID_RC80M 3

Internal 80 MHz RC oscillator.

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

#define OSC_ID_RCFAST 4

Internal 4-8-12 MHz RCFAST oscillator.

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

#define OSC_ID_RCSYS 6

Internal System RC oscillator.

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

#define OSC_MODE_EXTERNAL 0

External clock connected to XIN.

#define OSC_MODE_XTAL SCIF_OSCCTRL0_MODE

Crystal connected to XIN/XOUT.

#define OSC_RC1M_NOMINAL_HZ 1000000

Nominal frequency of RC1M in Hz.

Referenced by osc_get_rate(), and sysclk_get_main_hz().

#define OSC_RC32K_MAX_HZ 44000

Maximum frequency of RC32K in Hz.

#define OSC_RC32K_MIN_HZ 20000

Minimum frequency of RC32K in Hz.

#define OSC_RC32K_NOMINAL_HZ 32768

Nominal frequency of RC32K in Hz.

Referenced by dfll_priv_get_source_hz(), main(), osc_get_rate(), and wdt_set_ctrl().

#define OSC_RC80M_NOMINAL_HZ 80000000

Nominal frequency of RC80M in Hz.

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

#define OSC_RCFAST12M_NOMINAL_HZ 12000000

Nominal frequency of RCFAST12M in Hz.

Referenced by osc_get_rate(), and sysclk_get_main_hz().

#define OSC_RCFAST4M_NOMINAL_HZ 4000000

Nominal frequency of RCFAST4M in Hz.

Referenced by osc_get_rate(), and sysclk_get_main_hz().

#define OSC_RCFAST8M_NOMINAL_HZ 8000000

Nominal frequency of RCFAST8M in Hz.

Referenced by osc_get_rate(), and sysclk_get_main_hz().

#define OSC_RCSYS_MAX_HZ 120000

Maximum frequency of RCSYS in Hz.

#define OSC_RCSYS_MIN_HZ 100000

Minimum frequency of RCSYS in Hz.

#define OSC_RCSYS_NOMINAL_HZ 115000

Nominal frequency of RCSYS in Hz.

Referenced by dfll_priv_get_source_hz(), main(), osc_get_rate(), sysclk_get_main_hz(), and wdt_set_ctrl().

#define OSC_STARTUP_0 SCIF_OSCCTRL0_STARTUP(0)

0 cycles

#define OSC_STARTUP_128 SCIF_OSCCTRL0_STARTUP(2)

128 cycles (1.1 ms)

#define OSC_STARTUP_16384 SCIF_OSCCTRL0_STARTUP(6)

16384 cycles (143 ms)

#define OSC_STARTUP_2048 SCIF_OSCCTRL0_STARTUP(3)

2048 cycles (18 ms)

#define OSC_STARTUP_32768 SCIF_OSCCTRL0_STARTUP(7)

32768 cycles (285 ms)

#define OSC_STARTUP_4096 SCIF_OSCCTRL0_STARTUP(4)

4096 cycles (36 ms)

#define OSC_STARTUP_64 SCIF_OSCCTRL0_STARTUP(1)

64 cycles (560 us)

#define OSC_STARTUP_8192 SCIF_OSCCTRL0_STARTUP(5)

8192 cycles (71 ms)

void osc_disable ( uint8_t id )

inlinestatic

Disable oscillator id.

References OSC_ID_OSC0, OSC_ID_OSC32, OSC_ID_RC1M, OSC_ID_RC32K, OSC_ID_RC80M, OSC_ID_RCFAST, OSC_ID_RCSYS, osc_priv_disable_osc0(), osc_priv_disable_osc32(), osc_priv_disable_rc1m(), osc_priv_disable_rc32k(), osc_priv_disable_rc80m(), and osc_priv_disable_rcfast().

Referenced by main().

void osc_enable ( uint8_t id )

inlinestatic

Enable oscillator id.

The startup time and mode value is automatically determined based on definitions in the board code.

References OSC_ID_OSC0, OSC_ID_OSC32, OSC_ID_RC1M, OSC_ID_RC32K, OSC_ID_RC80M, OSC_ID_RCFAST, OSC_ID_RCSYS, osc_priv_enable_osc0(), osc_priv_enable_osc32(), osc_priv_enable_rc1m(), osc_priv_enable_rc32k(), osc_priv_enable_rc80m(), and osc_priv_enable_rcfast().

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

uint32_t osc_get_rate ( uint8_t id )

inlinestatic

Return the frequency of oscillator id in Hz.

References BOARD_OSC0_HZ, BOARD_OSC32_HZ, CONFIG_RCFAST_FRANGE, OSC_ID_OSC0, OSC_ID_OSC32, OSC_ID_RC1M, OSC_ID_RC32K, OSC_ID_RC80M, OSC_ID_RCFAST, OSC_ID_RCSYS, OSC_RC1M_NOMINAL_HZ, OSC_RC32K_NOMINAL_HZ, OSC_RC80M_NOMINAL_HZ, OSC_RCFAST12M_NOMINAL_HZ, OSC_RCFAST4M_NOMINAL_HZ, OSC_RCFAST8M_NOMINAL_HZ, and OSC_RCSYS_NOMINAL_HZ.

Referenced by pll_config_init().

osc_is_ready ( uint8_t id )

inlinestatic

Determine whether oscillator id is ready.

Return values

true	Oscillator id is running and ready to use as a clock source.
false	Oscillator id is not running.

References OSC_ID_OSC0, OSC_ID_OSC32, OSC_ID_RC1M, OSC_ID_RC32K, OSC_ID_RC80M, OSC_ID_RCFAST, and OSC_ID_RCSYS.

Referenced by dfll_enable_source(), genclk_enable_source(), osc_wait_ready(), and pll_enable_source().

void osc_priv_disable_osc0 ( void )

Referenced by osc_disable().

void osc_priv_disable_osc32 ( void )

Referenced by osc_disable().

void osc_priv_disable_rc1m ( void )

References cpu_irq_restore(), and cpu_irq_save().

Referenced by osc_disable().

void osc_priv_disable_rc32k ( void )

References cpu_irq_restore(), and cpu_irq_save().

Referenced by osc_disable().

void osc_priv_disable_rc80m ( void )

References cpu_irq_restore(), and cpu_irq_save().

Referenced by osc_disable().

void osc_priv_disable_rcfast ( void )

References cpu_irq_restore(), and cpu_irq_save().

Referenced by osc_disable().

void osc_priv_enable_osc0 ( void )

Referenced by osc_enable().

void osc_priv_enable_osc32 ( void )

Referenced by osc_enable().

void osc_priv_enable_rc1m ( void )

References cpu_irq_restore(), and cpu_irq_save().

Referenced by osc_enable().

void osc_priv_enable_rc32k ( void )

References cpu_irq_restore(), and cpu_irq_save().

Referenced by osc_enable().

void osc_priv_enable_rc80m ( void )

References cpu_irq_restore(), and cpu_irq_save().

Referenced by osc_enable().

void osc_priv_enable_rcfast ( void )

References CONFIG_RCFAST_FRANGE, cpu_irq_restore(), and cpu_irq_save().

Referenced by osc_enable().

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

Microchip® Advanced Software Framework

Board-specific Definitions

Macros

Functions

Oscillator Management

Oscillator identifiers

OSC0 mode values

OSC32 mode values

OSC0 startup values

OSC32 startup values

RC oscillator frequency limits