1/*
2 * @brief Systick example using systick timer, the SYSTICK clock divider, and the LED
3 *
4 * @note
5 * Copyright(C) NXP Semiconductors, 2013
6 * All rights reserved.
7 *
8 * @par
9 * Software that is described herein is for illustrative purposes only
10 * which provides customers with programming information regarding the
11 * LPC products.  This software is supplied "AS IS" without any warranties of
12 * any kind, and NXP Semiconductors and its licensor disclaim any and
13 * all warranties, express or implied, including all implied warranties of
14 * merchantability, fitness for a particular purpose and non-infringement of
15 * intellectual property rights.  NXP Semiconductors assumes no responsibility
16 * or liability for the use of the software, conveys no license or rights under any
17 * patent, copyright, mask work right, or any other intellectual property rights in
18 * or to any products. NXP Semiconductors reserves the right to make changes
19 * in the software without notification. NXP Semiconductors also makes no
20 * representation or warranty that such application will be suitable for the
21 * specified use without further testing or modification.
22 *
23 * @par
24 * Permission to use, copy, modify, and distribute this software and its
25 * documentation is hereby granted, under NXP Semiconductors' and its
26 * licensor's relevant copyrights in the software, without fee, provided that it
27 * is used in conjunction with NXP Semiconductors microcontrollers.  This
28 * copyright, permission, and disclaimer notice must appear in all copies of
29 * this code.
30 */
31
32/** @defgroup EXAMPLES_PERIPH_15XX_SYSTICK LPC15xx Simple systick example
33 * @ingroup EXAMPLES_PERIPH_15XX
34 * <b>Example description</b><br>
35 * The Systick example simply blinks an LED at a periodic rate using the systick
36 * timer and SYSTICK clock divider. The LED state is toggled in the systick
37 * interrupt handler.<br>
38 *
39 * <b>NOTE</b><br>
40 * While one would expect a clock divider to delay an interrupt occurrence this implementation
41 * seems to hasten the interrupt occurrence. For example, if the SYSTICK clock divider is set
42 * to 1, 453 interrupts occur in a 30-second interval.  If the SYSTICK clock divider is set
43 * to 2, one would expect to see half the interrupt count however twice the interrupts occure as
44 * though the clock divider were really a clock multiplier.<br>
45 *
46 * <b>NOTE</b><br>
47 * In addition, once the SYSTICK clock divider is set and SYSTICK is enabled, the SYSTICK clock
48 * divider becomes static, changes seem to have no effect.  Once the clock was running, the effective
49 * rate could not be changed or the SYSTICK timer clock disabled as described in the UM.
50 *
51 * <b>Special connection requirements</b><br>
52 * There are no special connection requirements for this example.<br>
53 *
54 * <b>Build procedures:</b><br>
55 * Visit the <a href="http://www.lpcware.com/content/project/lpcopen-platform-nxp-lpc-microcontrollers/lpcopen-v200-quickstart-guides">LPCOpen quickstart guides</a>
56 * to get started building LPCOpen projects.
57 *
58 * <b>Supported boards and board setup:</b><br>
59 * @ref LPCOPEN_15XX_BOARD_LPCXPRESSO_1549<br>
60 *
61 * <b>Submitting LPCOpen issues:</b><br>
62 * @ref LPCOPEN_COMMUNITY
63 * @{
64 */
65
66/**
67 * @}
68 */
69