1 /*
2 * @brief LPC15xx Chip specific SystemInit
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 #include "chip.h"
33
34 /*****************************************************************************
35 * Private types/enumerations/variables
36 ****************************************************************************/
37
38 /*****************************************************************************
39 * Public types/enumerations/variables
40 ****************************************************************************/
41
42 /*****************************************************************************
43 * Private functions
44 ****************************************************************************/
45
46 /*****************************************************************************
47 * Public functions
48 ****************************************************************************/
49
50 /* Clock and PLL initialization based on the internal oscillator */
Chip_SetupIrcClocking(void)51 void Chip_SetupIrcClocking(void)
52 {
53 volatile int i;
54
55 /* Powerup main IRC (likely already powered up) */
56 Chip_SYSCTL_PowerUp(SYSCTL_POWERDOWN_IRC_PD);
57 Chip_SYSCTL_PowerUp(SYSCTL_POWERDOWN_IRCOUT_PD);
58
59 /* Set system PLL input to IRC */
60 Chip_Clock_SetSystemPLLSource(SYSCTL_PLLCLKSRC_IRC);
61
62 /* Power down PLL to change the PLL divider ratio */
63 Chip_SYSCTL_PowerDown(SYSCTL_POWERDOWN_SYSPLL_PD);
64
65 /* Setup PLL for main oscillator rate (FCLKIN = 12MHz) * 6 = 72MHz
66 MSEL = 5 (this is pre-decremented), PSEL = 1 (for P = 2)
67 FCLKOUT = FCLKIN * (MSEL + 1) = 12MHz * 6 = 72MHz
68 FCCO = FCLKOUT * 2 * P = 72MHz * 2 * 2 = 288MHz (within FCCO range) */
69 Chip_Clock_SetupSystemPLL(5, 2);
70
71 /* Powerup system PLL */
72 Chip_SYSCTL_PowerUp(SYSCTL_POWERDOWN_SYSPLL_PD);
73
74 /* Wait for PLL to lock */
75 while (!Chip_Clock_IsSystemPLLLocked()) {}
76
77 /* Set system clock divider to 1 */
78 Chip_Clock_SetSysClockDiv(1);
79
80 /* Setup FLASH access timing for 72MHz */
81 Chip_FMC_SetFLASHAccess(SYSCTL_FLASHTIM_72MHZ_CPU);
82
83 /* Set main clock source to the system PLL. This will drive 72MHz
84 for the main clock */
85 Chip_Clock_SetMainClockSource(SYSCTL_MAINCLKSRC_SYSPLLOUT);
86 }
87
88 /* Clock and PLL initialization based on the external oscillator */
Chip_SetupXtalClocking(void)89 void Chip_SetupXtalClocking(void)
90 {
91 volatile int i;
92
93 /* Powerup main oscillator */
94 Chip_SYSCTL_PowerUp(SYSCTL_POWERDOWN_SYSOSC_PD);
95
96 /* Wait 200us for OSC to be stablized, no status
97 indication, dummy wait. */
98 for (i = 0; i < 0x200; i++) {}
99
100 /* Set system PLL input to main oscillator */
101 Chip_Clock_SetSystemPLLSource(SYSCTL_PLLCLKSRC_MAINOSC);
102
103 /* Power down PLL to change the PLL divider ratio */
104 Chip_SYSCTL_PowerDown(SYSCTL_POWERDOWN_SYSPLL_PD);
105
106 /* Setup PLL for main oscillator rate (FCLKIN = 12MHz) * 6 = 72MHz
107 MSEL = 5 (this is pre-decremented), PSEL = 1 (for P = 2)
108 FCLKOUT = FCLKIN * (MSEL + 1) = 12MHz * 6 = 72MHz
109 FCCO = FCLKOUT * 2 * P = 72MHz * 2 * 2 = 288MHz (within FCCO range) */
110 Chip_Clock_SetupSystemPLL(5, 2);
111
112 /* Powerup system PLL */
113 Chip_SYSCTL_PowerUp(SYSCTL_POWERDOWN_SYSPLL_PD);
114
115 /* Wait for PLL to lock */
116 while (!Chip_Clock_IsSystemPLLLocked()) {}
117
118 /* Set system clock divider to 1 */
119 Chip_Clock_SetSysClockDiv(1);
120
121 /* Setup FLASH access timing for 72MHz */
122 Chip_FMC_SetFLASHAccess(SYSCTL_FLASHTIM_72MHZ_CPU);
123
124 /* Set main clock source to the system PLL. This will drive 72MHz
125 for the main clock */
126 Chip_Clock_SetMainClockSource(SYSCTL_MAINCLKSRC_SYSPLLOUT);
127 }
128
129 /* Set up and initialize hardware prior to call to main */
Chip_SystemInit(void)130 void Chip_SystemInit(void)
131 {
132 /* Initial internal clocking */
133 Chip_SetupIrcClocking();
134 }
135