Busy-Wait Delay Routines

This module provides simple loop-based delay routines for those applications requiring a brief wait during execution.

Common API for UC3, XMEGA, and AVR MEGA.

Macros
#define	delay_init(fcpu_hz)
	Initialize the delay driver. More...
#define	delay_ms(delay)   ((delay) ? cpu_delay_ms(delay, F_CPU) : cpu_delay_us(1, F_CPU))
	Delay in milliseconds. More...
#define	delay_s(delay)   ((delay) ? cpu_delay_ms(1000 * delay, F_CPU) : cpu_delay_us(1, F_CPU))
	Delay in seconds. More...
#define	delay_us(delay)   ((delay) ? cpu_delay_us(delay, F_CPU) : cpu_delay_us(1, F_CPU))
	Delay in microseconds. More...
#define	F_CPU   sysclk_get_cpu_hz()
	MCU Clock Frequency (Hertz) More...

#define delay_init

(

fcpu_hz

)

Initialize the delay driver.

Parameters

fcpu_hz

CPU frequency in Hz

Deprecated:

This function is provided for compatibility with ASF applications that may not have been updated to configure the system clock via the common clock service; e.g. sysclk_init() and a configuration header file are used to configure clocks.

The functions in this module call sysclk_get_cpu_hz() function to obtain the system clock frequency.

#define delay_ms

(

delay

)

((delay) ? cpu_delay_ms(delay, F_CPU) : cpu_delay_us(1, F_CPU))

Delay in milliseconds.

Parameters

delay

Delay in milliseconds

Referenced by run_freqm_test().

#define delay_s

(

delay

)

((delay) ? cpu_delay_ms(1000 * delay, F_CPU) : cpu_delay_us(1, F_CPU))

Delay in seconds.

Parameters

delay

Delay in seconds

#define delay_us

(

delay

)

((delay) ? cpu_delay_us(delay, F_CPU) : cpu_delay_us(1, F_CPU))

Delay in microseconds.

Parameters

delay

Delay in microseconds

#define F_CPU   sysclk_get_cpu_hz()

MCU Clock Frequency (Hertz)

Deprecated:

The F_CPU configuration constant is used for compatibility with the Busy-Wait Delay Routines routines. The common loop-based delay routines are designed to use the Clock Management modules while anticipating support for legacy applications assuming a statically defined clock frequency. Applications using a statically configured MCU clock frequency can define F_CPU (Hertz), in which case the common delay routines will use this value rather than calling sysclk_get_cpu_hz() to get the current MCU clock frequency.