- /* Teensyduino Core Library
- * http://www.pjrc.com/teensy/
- * Copyright (c) 2013 PJRC.COM, LLC.
- * Modifications by Jacob Alexander 2013-2014
- *
- * Permission is hereby granted, free of charge, to any person obtaining
- * a copy of this software and associated documentation files (the
- * "Software"), to deal in the Software without restriction, including
- * without limitation the rights to use, copy, modify, merge, publish,
- * distribute, sublicense, and/or sell copies of the Software, and to
- * permit persons to whom the Software is furnished to do so, subject to
- * the following conditions:
- *
- * 1. The above copyright notice and this permission notice shall be
- * included in all copies or substantial portions of the Software.
- *
- * 2. If the Software is incorporated into a build system that allows
- * selection among a list of target devices, then similar target
- * devices manufactured by PJRC.COM must be included in the list of
- * target devices and selectable in the same manner.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
- * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
- * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
- * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
- * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
- * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
- * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
-
- // ----- Local Includes -----
-
- #include "delay.h"
- #include "mk20dx.h"
-
-
-
- // ----- Variables -----
-
- // the systick interrupt is supposed to increment this at 1 kHz rate
- volatile uint32_t systick_millis_count = 0;
-
-
-
- // ----- Functions -----
-
- void yield(void) {};
-
- uint32_t micros(void)
- {
- uint32_t count, current, istatus;
-
- __disable_irq();
- current = SYST_CVR;
- count = systick_millis_count;
- istatus = SCB_ICSR; // bit 26 indicates if systick exception pending
- __enable_irq();
- if ((istatus & SCB_ICSR_PENDSTSET) && current > ((F_CPU / 1000) - 50)) count++;
- current = ((F_CPU / 1000) - 1) - current;
- return count * 1000 + current / (F_CPU / 1000000);
- }
-
- void delay(uint32_t ms)
- {
- uint32_t start = micros();
-
- while (1) {
- if ((micros() - start) >= 1000) {
- ms--;
- if (ms == 0) break;
- start += 1000;
- }
- yield();
- }
- }
-
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