mbed library sources
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Diff: targets/cmsis/TARGET_NORDIC/TARGET_MCU_NRF51822/system_nrf51822.c
- Revision:
- 270:e2babe29baf8
- Parent:
- 127:ce7cebc0511f
- Child:
- 304:89b9c3a9a045
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/targets/cmsis/TARGET_NORDIC/TARGET_MCU_NRF51822/system_nrf51822.c Fri Aug 01 14:45:06 2014 +0100 @@ -0,0 +1,107 @@ +/* mbed Microcontroller Library + + * Copyright (c) 2013 Nordic Semiconductor. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + + +#include <stdint.h> +#include <stdbool.h> +#include "nrf51822.h" +#include "system_nrf51822.h" + + +#define __SYSTEM_CLOCK (16000000UL) //!< nRF51 devices use a fixed System Clock Frequency of 16MHz + +static bool is_manual_peripheral_setup_needed(void); +static bool is_disabled_in_debug_needed(void); + + +#if defined ( __CC_ARM ) + uint32_t SystemCoreClock __attribute__((used)) = __SYSTEM_CLOCK; +#elif defined ( __ICCARM__ ) + __root uint32_t SystemCoreClock = __SYSTEM_CLOCK; +#elif defined ( __GNUC__ ) + uint32_t SystemCoreClock __attribute__((used)) = __SYSTEM_CLOCK; +#endif + + +void SystemCoreClockUpdate(void) +{ + SystemCoreClock = __SYSTEM_CLOCK; +} + +void SystemInit(void) +{ + // Prepare the peripherals for use as indicated by the PAN 26 "System: Manual setup is required + // to enable the use of peripherals" found at Product Anomaly document for your device found at + // https://www.nordicsemi.com/. The side effect of executing these instructions in the devices + // that do not need it is that the new peripherals in the second generation devices (LPCOMP for + // example) will not be available. + if (is_manual_peripheral_setup_needed()){ + *(uint32_t volatile *)0x40000504 = 0xC007FFDF; + *(uint32_t volatile *)0x40006C18 = 0x00008000; + } + + // Disable PROTENSET registers under debug, as indicated by PAN 59 "MPU: Reset value of DISABLEINDEBUG + // register is incorrect" found at Product Anomaly document four your device found at + // https://www.nordicsemi.com/. There is no side effect of using these instruction if not needed. + if (is_disabled_in_debug_needed()){ + NRF_MPU->DISABLEINDEBUG = MPU_DISABLEINDEBUG_DISABLEINDEBUG_Disabled << MPU_DISABLEINDEBUG_DISABLEINDEBUG_Pos; + } + + // Start 16 MHz crystal oscillator. + NRF_CLOCK->EVENTS_HFCLKSTARTED = 0; + NRF_CLOCK->TASKS_HFCLKSTART = 1; + + // Wait for the external oscillator to start up. + while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0) { + // Do nothing. + } +} + +static bool is_manual_peripheral_setup_needed(void) +{ + if ((((*(uint32_t *)0xF0000FE0) & 0x000000FF) == 0x1) && (((*(uint32_t *)0xF0000FE4) & 0x0000000F) == 0x0)) + { + if ((((*(uint32_t *)0xF0000FE8) & 0x000000F0) == 0x00) && (((*(uint32_t *)0xF0000FEC) & 0x000000F0) == 0x0)) + { + return true; + } + if ((((*(uint32_t *)0xF0000FE8) & 0x000000F0) == 0x10) && (((*(uint32_t *)0xF0000FEC) & 0x000000F0) == 0x0)) + { + return true; + } + if ((((*(uint32_t *)0xF0000FE8) & 0x000000F0) == 0x30) && (((*(uint32_t *)0xF0000FEC) & 0x000000F0) == 0x0)) + { + return true; + } + } + + return false; +} + +static bool is_disabled_in_debug_needed(void) +{ + if ((((*(uint32_t *)0xF0000FE0) & 0x000000FF) == 0x1) && (((*(uint32_t *)0xF0000FE4) & 0x0000000F) == 0x0)) + { + if ((((*(uint32_t *)0xF0000FE8) & 0x000000F0) == 0x40) && (((*(uint32_t *)0xF0000FEC) & 0x000000F0) == 0x0)) + { + return true; + } + } + + return false; +} +