libopencm3 Defined Constants and Types for the Cortex SysTick More...

Collaboration diagram for Cortex-M SysTick Defines:

Modules
	STK_CSR Values

	STK_RVR Values

	STK_CALIB Values

Macros
#define	STK_CSR MMIO32(SYS_TICK_BASE + 0x00)
	SysTick Control and Status Register (CSR). More...

#define	STK_RVR MMIO32(SYS_TICK_BASE + 0x04)
	SysTick Reload Value Register (RVR). More...

#define	STK_CVR MMIO32(SYS_TICK_BASE + 0x08)
	SysTick Current Value Register (CVR). More...

#define	STK_CALIB MMIO32(SYS_TICK_BASE + 0x0C)
	SysTick Calibration Value Register(Read Only) (CALIB) Reads the calibration value and parameters for SysTick. More...

Functions
void	systick_set_reload (uint32_t value)

bool	systick_set_frequency (uint32_t freq, uint32_t ahb)

uint32_t	systick_get_reload (void)

uint32_t	systick_get_value (void)

void	systick_set_clocksource (uint8_t clocksource)

void	systick_interrupt_enable (void)

void	systick_interrupt_disable (void)

void	systick_counter_enable (void)

void	systick_counter_disable (void)

uint8_t	systick_get_countflag (void)

void	systick_clear (void)

uint32_t	systick_get_calib (void)

Detailed Description

libopencm3 Defined Constants and Types for the Cortex SysTick

Version: 1.0.0

Author: © 2010 Thomas Otto tommi.nosp@m.@via.nosp@m.dmin..nosp@m.org

Date: 19 August 2012

System Control Space (SCS) => System timer register support in the SCS. To configure SysTick, load the interval required between SysTick events to the SysTick Reload Value register. The timer interrupt, or COUNTFLAG bit in the SysTick Control and Status register, is activated on the transition from 1 to 0, therefore it activates every n+1 clock ticks. If you require a period of 100, write 99 to the SysTick Reload Value register. The SysTick Reload Value register supports values between 0x1 and 0x00FFFFFF.

If you want to use SysTick to generate an event at a timed interval, for example 1ms, you can use the SysTick Calibration Value Register to scale your value for the Reload register. The SysTick Calibration Value Register is a read-only register that contains the number of pulses for a period of 10ms, in the TENMS field, bits[23:0].

This register also has a SKEW bit. Bit[30] == 1 indicates that the calibration for 10ms in the TENMS section is not exactly 10ms due to clock frequency. Bit[31] == 1 indicates that the reference clock is not provided.

LGPL License Terms libopencm3 License

Macro Definition Documentation

◆ STK_CALIB

#define STK_CALIB MMIO32(SYS_TICK_BASE + 0x0C)

SysTick Calibration Value Register(Read Only) (CALIB) Reads the calibration value and parameters for SysTick.

Usage constraints: There are no usage constraints. Configurations Always implemented.

Definition at line 90 of file systick.h.

◆ STK_CSR

#define STK_CSR MMIO32(SYS_TICK_BASE + 0x00)

SysTick Control and Status Register (CSR).

Controls the system timer and provides status data. Usage constraints: There are no usage constraints. Configurations Always implemented.

Definition at line 66 of file systick.h.

◆ STK_CVR

#define STK_CVR MMIO32(SYS_TICK_BASE + 0x08)

SysTick Current Value Register (CVR).

Holds the current value of the counter. Usage constraints: There are no usage constraints. Configurations Always implemented.

Definition at line 83 of file systick.h.

◆ STK_RVR

#define STK_RVR MMIO32(SYS_TICK_BASE + 0x04)

SysTick Reload Value Register (RVR).

Reads or clears the value that will be loaded to the counter. Usage constraints:

Any write to the register clears the register to zero.
The counter does not provide read-modify-write protection.
Unsupported bits are read as zero Configurations Always implemented.

Definition at line 76 of file systick.h.

Function Documentation

◆ systick_clear()

void systick_clear ( void )

◆ systick_counter_disable()

void systick_counter_disable ( void )

◆ systick_counter_enable()

void systick_counter_enable ( void )

◆ systick_get_calib()

uint32_t systick_get_calib ( void )

◆ systick_get_countflag()

uint8_t systick_get_countflag ( void )

◆ systick_get_reload()

uint32_t systick_get_reload ( void )

◆ systick_get_value()

uint32_t systick_get_value ( void )

◆ systick_interrupt_disable()

void systick_interrupt_disable ( void )

◆ systick_interrupt_enable()

void systick_interrupt_enable ( void )

◆ systick_set_clocksource()

void systick_set_clocksource ( uint8_t clocksource )

◆ systick_set_frequency()

bool systick_set_frequency	(	uint32_t	freq,
		uint32_t	ahb
	)

◆ systick_set_reload()

void systick_set_reload ( uint32_t value )

Modules

Macros

Functions