Scheduler Example

CleverOS Boot

Start the CleverOS runtime with two tasks, SysTick, PendSV context switching, LED output, and serial logs.

Board LPCXpresso51U68 EVB OM40005

Status Verified

Download lpc51u68_cleveros_boot_main.c

Run It

Use these commands from the COS workspace when the board and serial adapter are attached.

make -C firmware/lpc51u68_cleveros_boot clean allmake -C firmware/lpc51u68_cleveros_boot flashpython3 tools/uart_viewer.py --device <serial-device> --baud 9600

What To Look For

rtos_init receives task entry points.
SysTick drives scheduler timing.
PendSV switches between the two task contexts.

Download Code From This Website Open Repository

#include <stdint.h>

#include "cos_lpc51u68_bsp.h"
#include "cos_lpc51u68_rtos.h"

static void task_uart(void)
{
    uint32_t count = 0u;

    for (;;) {
        rtos_log_task_state("rtos task0 uart tick ", rtos_tick_ms(), count++);
        rtos_delay_ticks(1000u);
    }
}

static void task_led(void)
{
    uint32_t count = 0u;
    cos_lpc51u68_led_step_t step = COS_LPC51U68_LED_STEP_RED;

    for (;;) {
        rtos_set_led_step(step);
        rtos_log_task_state("rtos task1 led tick ", rtos_tick_ms(), count++);
        step = (cos_lpc51u68_led_step_t)(((uint32_t)step + 1u) & 0x3u);
        rtos_delay_ticks(1000u);
    }
}

int main(void)
{
    cos_lpc51u68_uart0_init_9600_8n1();
    cos_lpc51u68_gpio_leds_init();
    cos_lpc51u68_uart0_puts("\r\nCleverOS first boot on LPC51U68\r\n");

    rtos_init(task_uart, task_led);
    cos_lpc51u68_systick_init_1ms();
    rtos_boot_scheduler();

    for (;;) {
        __asm volatile("wfi");
    }
}