#include <rtl.h>

int os_tick_init (void);

The os_tick_init function initializes the hardware timer as a system tick timer and starts it. It is used in Cortex™-M library, if you want to use alternate peripheral timer as RTX tick timer. If this function does not exist in a project, the default SysTick timer is used as RTX tick timer.

The os_tick_init function is part of RL-RTX. The prototype is defined in rtl.h. You can customize the function in rtx_config.c.

Note

• The os_tick_init function is used in Alternate Tick Timer configuration. It is not supported in ARM7™/ARM9™ library version.

The os_tick_init function returns the Cortex-M interrupt number of alternate peripheral timer.

OS_Tick_Handler, os_tick_irqack

#include <rtl.h>

int os_tick_init (void) {
  /* Initialize hardware timer as system tick timer. */

  LPC_SC->PCONP     |=  (1<<16);   // Enable power for RIT
  LPC_SC->PCLKSEL1  &= ~(3<<26);
  LPC_SC->PCLKSEL1  |=  (1<<26);   // RIT Clock = CCLK

  LPC_RIT->RICOMPVAL = OS_TRV;     // Set match value
  LPC_RIT->RICOUNTER = 0;          // Set count value to 0
  LPC_RIT->RICTRL    = (1<<3) |    // Timer enable
                       (1<<1) |    // Enable clear on match
                       (1<<0);     // Clear interrupt flag

  return (RIT_IRQn);  /* Return IRQ number of timer (0..239) */
}