Clock driver

Files
file	clock-arch.c
	Software clock implementation for the gecko.

Functions
void	clock_init (void)
	Initialize the clock library.
clock_time_t	clock_time (void)
	Get the current clock time.
unsigned long	clock_seconds (void)
	Get the current value of the platform seconds.
void	clock_wait (clock_time_t i)
	Wait for a given number of ticks.
void	clock_delay_usec (uint16_t dt)
	Delay a given number of microseconds.
void	clock_delay (unsigned int i)
	Obsolete delay function but we implement it here since some code still uses it.

Detailed Description

Function Documentation

clock_delay_usec()

void clock_delay_usec

(

uint16_t

dt

)

Delay a given number of microseconds.

Parameters

dt	How many microseconds to delay.

Note

Interrupts could increase the delay by a variable amount.

< GPTIMER0

< GPTM Timer A interval load

< GPTIMER0

< GPTM control

< Timer A enable

< GPTIMER0

< GPTM control

< Timer A enable

Definition at line 114 of file clock-arch.c.

Referenced by clock_delay(), and clock_wait().

clock_init()

void clock_init

(

void

)

Initialize the clock library.

This function initializes the clock library and should be called from the main() function of the system.

Initialize the clock library.

We initialise the SysTick to fire 128 interrupts per second, giving us a value of 128 for CLOCK_SECOND

We also initialise GPT0:Timer A, which is used by clock_delay_usec(). We use 16-bit range (individual), count-down, one-shot, no interrupts. The prescaler is computed according to the system clock in order to get 1 tick per usec.

< GPT[3:0] clocks - active mode

< GPT0 clock enable, CPU running

< GPTIMER0

< GPTM control

< GPTIMER0

< GPTM configuration

< GPTIMER0

< GPTM Timer A mode

< GPTIMER0

< GPTM Timer A prescale

Definition at line 77 of file clock-arch.c.

clock_seconds()

unsigned long clock_seconds

(

void

)

Get the current value of the platform seconds.

This could be the number of seconds since startup, or since a standard epoch.

Returns

The value.

Definition at line 98 of file clock-arch.c.

clock_time()

clock_time_t clock_time

(

void

)

Get the current clock time.

This function returns the current system clock time.

Returns

The current clock time, measured in system ticks.

Definition at line 92 of file clock-arch.c.

Referenced by clock_wait().

clock_wait()

void clock_wait

(

clock_time_t

t

)

Wait for a given number of ticks.

Parameters

t	How many ticks.

Definition at line 104 of file clock-arch.c.

References clock_time(), and start().