zephyrCommon: improve delay* accurancy

cores/arduino/Arduino.h

@@ -116,6 +116,8 @@ int digitalPinToInterrupt(pin_size_t pin);
 #define LED_BUILTIN ZARD_LED_BUILTIN
 #endif // LED_BUILTIN
 
+#include <inlines.h>
+
 #ifdef __cplusplus
 #include <zephyrSerial.h>
 #endif // __cplusplus

cores/arduino/inlines.h

@@ -0,0 +1,27 @@
+/*
+ * Copyright (c) Arduino s.r.l. and/or its affiliated companies
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/*
+ * Provide implementations for inline functions.
+ */
+
+#ifndef __INLINES_H__
+#define __INLINES_H__
+
+#include <zephyr/kernel.h>
+
+inline __attribute__((always_inline)) void delay(unsigned long ms) {
+	k_sleep(K_MSEC(ms));
+}
+
+inline __attribute__((always_inline)) void delayMicroseconds(unsigned int us) {
+	if (us == 0) {
+		return;
+	}
+	k_busy_wait(us - 1);
+}
+
+#endif /* __INLINES_H__ */

cores/arduino/time_macros.h

@@ -0,0 +1,13 @@
+/*
+ * Copyright (c) Arduino s.r.l. and/or its affiliated companies
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#pragma once
+
+#include <zephyr/sys/time_units.h>
+
+#define clockCyclesPerMicrosecond()  (1000000 / k_cyc_to_ns_near64(1000))
+#define clockCyclesToMicroseconds(a) (a / clockCyclesPerMicrosecond())
+#define microsecondsToClockCycles(a) (a * clockCyclesPerMicrosecond())

cores/arduino/zephyrCommon.cpp

@@ -338,14 +338,6 @@ void noTone(pin_size_t pinNumber) {
 	gpio_pin_set_dt(&arduino_pins[pinNumber], 0);
 }
 
-void delay(unsigned long ms) {
-	k_sleep(K_MSEC(ms));
-}
-
-void delayMicroseconds(unsigned int us) {
-	k_busy_wait(us);
-}
-
 unsigned long micros(void) {
 	return k_cyc_to_us_floor32(k_cycle_get_32());
 }