Erik Fountain / NorAmMote_PA_Test

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Dependents:   PA_Boost_test

Fork of mbed-src by mbed official

targets/cmsis/TARGET_NORDIC/TARGET_MCU_NRF51822/system_nrf51822.c@305:89b9c3a9a045, 2014-08-29 (annotated)

Committer:
mbed_official
Date:
Fri Aug 29 17:15:07 2014 +0100
Revision:
305:89b9c3a9a045
Parent:
270:e2babe29baf8
Child:
307:d33324c3b5a2
Synchronized with git revision 734f365d7da26ef199751f4b0d91611479b495ea



Full URL: https://github.com/mbedmicro/mbed/commit/734f365d7da26ef199751f4b0d91611479b495ea/



1. timestamp_t as an abstraction for time values managed by

   Ticker. Using uint64_t for timestamp_t allows a wraparound-free

   Ticker. This change forces us to update the definitions of usTicker

   for all platforms; but the changes beyond nRF51822 aren't major.



2. reduce power consumption on the nRF51822 by removing the need for

   the high-frequency processor timer; and reimplementing it using the

   RTC.



I've also replaced high-frequency clock with low-frequency external

clock during system startup of the nRF51822. This brings a major win

in power consumption.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mbed_official 85:e1a8e879a6a9 1 /* mbed Microcontroller Library
mbed_official 85:e1a8e879a6a9 2
mbed_official 104:a6a92e2e5a92 3 * Copyright (c) 2013 Nordic Semiconductor.
mbed_official 85:e1a8e879a6a9 4 *
mbed_official 85:e1a8e879a6a9 5 * Licensed under the Apache License, Version 2.0 (the "License");
mbed_official 85:e1a8e879a6a9 6 * you may not use this file except in compliance with the License.
mbed_official 85:e1a8e879a6a9 7 * You may obtain a copy of the License at
mbed_official 85:e1a8e879a6a9 8 *
mbed_official 85:e1a8e879a6a9 9 * http://www.apache.org/licenses/LICENSE-2.0
mbed_official 85:e1a8e879a6a9 10 *
mbed_official 85:e1a8e879a6a9 11 * Unless required by applicable law or agreed to in writing, software
mbed_official 85:e1a8e879a6a9 12 * distributed under the License is distributed on an "AS IS" BASIS,
mbed_official 85:e1a8e879a6a9 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
mbed_official 85:e1a8e879a6a9 14 * See the License for the specific language governing permissions and
mbed_official 85:e1a8e879a6a9 15 * limitations under the License.
mbed_official 85:e1a8e879a6a9 16 */
mbed_official 85:e1a8e879a6a9 17
mbed_official 85:e1a8e879a6a9 18
mbed_official 85:e1a8e879a6a9 19 #include <stdint.h>
mbed_official 85:e1a8e879a6a9 20 #include <stdbool.h>
mbed_official 85:e1a8e879a6a9 21 #include "nrf51822.h"
mbed_official 85:e1a8e879a6a9 22 #include "system_nrf51822.h"
mbed_official 85:e1a8e879a6a9 23
mbed_official 85:e1a8e879a6a9 24
mbed_official 85:e1a8e879a6a9 25 #define __SYSTEM_CLOCK (16000000UL) //!< nRF51 devices use a fixed System Clock Frequency of 16MHz
mbed_official 85:e1a8e879a6a9 26
mbed_official 85:e1a8e879a6a9 27 static bool is_manual_peripheral_setup_needed(void);
mbed_official 85:e1a8e879a6a9 28 static bool is_disabled_in_debug_needed(void);
mbed_official 85:e1a8e879a6a9 29
mbed_official 85:e1a8e879a6a9 30
mbed_official 85:e1a8e879a6a9 31 #if defined ( __CC_ARM )
mbed_official 305:89b9c3a9a045 32 uint32_t SystemCoreClock __attribute__((used)) = __SYSTEM_CLOCK;
mbed_official 85:e1a8e879a6a9 33 #elif defined ( __ICCARM__ )
mbed_official 85:e1a8e879a6a9 34 __root uint32_t SystemCoreClock = __SYSTEM_CLOCK;
mbed_official 85:e1a8e879a6a9 35 #elif defined ( __GNUC__ )
mbed_official 85:e1a8e879a6a9 36 uint32_t SystemCoreClock __attribute__((used)) = __SYSTEM_CLOCK;
mbed_official 85:e1a8e879a6a9 37 #endif
mbed_official 85:e1a8e879a6a9 38
mbed_official 85:e1a8e879a6a9 39
mbed_official 85:e1a8e879a6a9 40 void SystemCoreClockUpdate(void)
mbed_official 85:e1a8e879a6a9 41 {
mbed_official 85:e1a8e879a6a9 42 SystemCoreClock = __SYSTEM_CLOCK;
mbed_official 85:e1a8e879a6a9 43 }
mbed_official 85:e1a8e879a6a9 44
mbed_official 85:e1a8e879a6a9 45 void SystemInit(void)
mbed_official 305:89b9c3a9a045 46 {
mbed_official 85:e1a8e879a6a9 47 // Prepare the peripherals for use as indicated by the PAN 26 "System: Manual setup is required
mbed_official 85:e1a8e879a6a9 48 // to enable the use of peripherals" found at Product Anomaly document for your device found at
mbed_official 305:89b9c3a9a045 49 // https://www.nordicsemi.com/. The side effect of executing these instructions in the devices
mbed_official 85:e1a8e879a6a9 50 // that do not need it is that the new peripherals in the second generation devices (LPCOMP for
mbed_official 85:e1a8e879a6a9 51 // example) will not be available.
mbed_official 85:e1a8e879a6a9 52 if (is_manual_peripheral_setup_needed()){
mbed_official 85:e1a8e879a6a9 53 *(uint32_t volatile *)0x40000504 = 0xC007FFDF;
mbed_official 85:e1a8e879a6a9 54 *(uint32_t volatile *)0x40006C18 = 0x00008000;
mbed_official 85:e1a8e879a6a9 55 }
mbed_official 305:89b9c3a9a045 56
mbed_official 85:e1a8e879a6a9 57 // Disable PROTENSET registers under debug, as indicated by PAN 59 "MPU: Reset value of DISABLEINDEBUG
mbed_official 305:89b9c3a9a045 58 // register is incorrect" found at Product Anomaly document four your device found at
mbed_official 305:89b9c3a9a045 59 // https://www.nordicsemi.com/. There is no side effect of using these instruction if not needed.
mbed_official 85:e1a8e879a6a9 60 if (is_disabled_in_debug_needed()){
mbed_official 85:e1a8e879a6a9 61 NRF_MPU->DISABLEINDEBUG = MPU_DISABLEINDEBUG_DISABLEINDEBUG_Disabled << MPU_DISABLEINDEBUG_DISABLEINDEBUG_Pos;
mbed_official 85:e1a8e879a6a9 62 }
mbed_official 305:89b9c3a9a045 63
mbed_official 305:89b9c3a9a045 64 // Start the external 32khz crystal oscillator.
mbed_official 305:89b9c3a9a045 65 NRF_CLOCK->LFCLKSRC = (CLOCK_LFCLKSRC_SRC_Xtal << CLOCK_LFCLKSRC_SRC_Pos);
mbed_official 305:89b9c3a9a045 66 NRF_CLOCK->EVENTS_LFCLKSTARTED = 0;
mbed_official 305:89b9c3a9a045 67 NRF_CLOCK->TASKS_LFCLKSTART = 1;
mbed_official 85:e1a8e879a6a9 68
mbed_official 85:e1a8e879a6a9 69 // Wait for the external oscillator to start up.
mbed_official 305:89b9c3a9a045 70 while (NRF_CLOCK->EVENTS_LFCLKSTARTED == 0) {
mbed_official 85:e1a8e879a6a9 71 // Do nothing.
mbed_official 85:e1a8e879a6a9 72 }
mbed_official 85:e1a8e879a6a9 73 }
mbed_official 85:e1a8e879a6a9 74
mbed_official 305:89b9c3a9a045 75 static bool is_manual_peripheral_setup_needed(void)
mbed_official 85:e1a8e879a6a9 76 {
mbed_official 85:e1a8e879a6a9 77 if ((((*(uint32_t *)0xF0000FE0) & 0x000000FF) == 0x1) && (((*(uint32_t *)0xF0000FE4) & 0x0000000F) == 0x0))
mbed_official 85:e1a8e879a6a9 78 {
mbed_official 85:e1a8e879a6a9 79 if ((((*(uint32_t *)0xF0000FE8) & 0x000000F0) == 0x00) && (((*(uint32_t *)0xF0000FEC) & 0x000000F0) == 0x0))
mbed_official 85:e1a8e879a6a9 80 {
mbed_official 85:e1a8e879a6a9 81 return true;
mbed_official 85:e1a8e879a6a9 82 }
mbed_official 85:e1a8e879a6a9 83 if ((((*(uint32_t *)0xF0000FE8) & 0x000000F0) == 0x10) && (((*(uint32_t *)0xF0000FEC) & 0x000000F0) == 0x0))
mbed_official 85:e1a8e879a6a9 84 {
mbed_official 85:e1a8e879a6a9 85 return true;
mbed_official 85:e1a8e879a6a9 86 }
mbed_official 85:e1a8e879a6a9 87 if ((((*(uint32_t *)0xF0000FE8) & 0x000000F0) == 0x30) && (((*(uint32_t *)0xF0000FEC) & 0x000000F0) == 0x0))
mbed_official 85:e1a8e879a6a9 88 {
mbed_official 85:e1a8e879a6a9 89 return true;
mbed_official 85:e1a8e879a6a9 90 }
mbed_official 85:e1a8e879a6a9 91 }
mbed_official 305:89b9c3a9a045 92
mbed_official 85:e1a8e879a6a9 93 return false;
mbed_official 85:e1a8e879a6a9 94 }
mbed_official 85:e1a8e879a6a9 95
mbed_official 305:89b9c3a9a045 96 static bool is_disabled_in_debug_needed(void)
mbed_official 85:e1a8e879a6a9 97 {
mbed_official 85:e1a8e879a6a9 98 if ((((*(uint32_t *)0xF0000FE0) & 0x000000FF) == 0x1) && (((*(uint32_t *)0xF0000FE4) & 0x0000000F) == 0x0))
mbed_official 85:e1a8e879a6a9 99 {
mbed_official 85:e1a8e879a6a9 100 if ((((*(uint32_t *)0xF0000FE8) & 0x000000F0) == 0x40) && (((*(uint32_t *)0xF0000FEC) & 0x000000F0) == 0x0))
mbed_official 85:e1a8e879a6a9 101 {
mbed_official 85:e1a8e879a6a9 102 return true;
mbed_official 85:e1a8e879a6a9 103 }
mbed_official 85:e1a8e879a6a9 104 }
mbed_official 305:89b9c3a9a045 105
mbed_official 85:e1a8e879a6a9 106 return false;
mbed_official 85:e1a8e879a6a9 107 }
mbed_official 85:e1a8e879a6a9 108