/bsp/k210:add delay us function in board.c ,when using posix interface ,rt_hw_us_delay this function will be called in unistd.c file
/*
- * Copyright (c) 2006-2018, RT-Thread Development Team
+ * Copyright (c) 2006-2021, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
+ *2021-06-10 xiaoyu implement rt_hw_us_delay()
*/
#include <rthw.h>
@@ -117,3 +118,19 @@ void rt_hw_cpu_reset(void)
}
MSH_CMD_EXPORT_ALIAS(rt_hw_cpu_reset, reboot, reset machine);
+
+/**
+ * This function will delay for some us.
+ *
+ * @param us the delay time of us
+ */
+void rt_hw_us_delay(rt_uint32_t usec)
+{
+ rt_uint32_t cycle = read_cycle();
+ rt_uint32_t nop_all = usec * sysctl_clock_get_freq(SYSCTL_CLOCK_CPU) / 1000000UL;
+ while (1)
+ {
+ if(read_cycle() - cycle >= nop_all)
+ break;
+ }
+}
