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