LPCOpen Platform for LPC18XX/43XX microcontrollers  18XX43XX
LPCOpen Platform for the NXP LPC18XX/43XX family of Microcontrollers
stopwatch_18xx_43xx.c
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1 /*
2  * @brief LPC18xx/43xx specific stopwatch implementation
3  *
4  * @note
5  * Copyright(C) NXP Semiconductors, 2014
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 #include "chip.h"
33 #include "stopwatch.h"
34 
35 /*****************************************************************************
36  * Private types/enumerations/variables
37  ****************************************************************************/
38 
39 /* Precompute these to optimize runtime */
40 static uint32_t ticksPerSecond;
41 static uint32_t ticksPerMs;
42 static uint32_t ticksPerUs;
43 
44 /*****************************************************************************
45  * Public types/enumerations/variables
46  ****************************************************************************/
47 
48 /*****************************************************************************
49  * Private functions
50  ****************************************************************************/
51 
52 /*****************************************************************************
53  * Public functions
54  ****************************************************************************/
55 
56 /* Initialize stopwatch */
57 void StopWatch_Init(void)
58 {
59  /* Use timer 1. Set prescaler to divide by 8 */
60  const uint32_t prescaleDivisor = 8;
62  Chip_TIMER_PrescaleSet(LPC_TIMER0, prescaleDivisor - 1);
64 
65  /* Pre-compute tick rate. */
66  ticksPerSecond = Chip_Clock_GetRate(CLK_MX_TIMER0) / prescaleDivisor;
67  ticksPerMs = ticksPerSecond / 1000;
68  ticksPerUs = ticksPerSecond / 1000000;
69 }
70 
71 /* Start a stopwatch */
72 uint32_t StopWatch_Start(void)
73 {
74  /* Return the current timer count. */
76 }
77 
78 /* Returns number of ticks per second of the stopwatch timer */
80 {
81  return ticksPerSecond;
82 }
83 
84 /* Converts from stopwatch ticks to mS. */
85 uint32_t StopWatch_TicksToMs(uint32_t ticks)
86 {
87  return ticks / ticksPerMs;
88 }
89 
90 /* Converts from stopwatch ticks to uS. */
91 uint32_t StopWatch_TicksToUs(uint32_t ticks)
92 {
93  return ticks / ticksPerUs;
94 }
95 
96 /* Converts from mS to stopwatch ticks. */
97 uint32_t StopWatch_MsToTicks(uint32_t mS)
98 {
99  return mS * ticksPerMs;
100 }
101 
102 /* Converts from uS to stopwatch ticks. */
103 uint32_t StopWatch_UsToTicks(uint32_t uS)
104 {
105  return uS * ticksPerUs;
106 }