1 // Copyright 2015-2017 Espressif Systems (Shanghai) PTE LTD 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 #pragma once 16 17 /** 18 * @file esp_clk_internal.h 19 * 20 * Private clock-related functions 21 */ 22 23 /** 24 * @brief Initialize clock-related settings 25 * 26 * Called from cpu_start.c, not intended to be called from other places. 27 * This function configures the CPU clock, RTC slow and fast clocks, and 28 * performs RTC slow clock calibration. 29 */ 30 void esp_clk_init(void); 31 32 33 /** 34 * @brief Disables clock of some peripherals 35 * 36 * Called from cpu_start.c, not intended to be called from other places. 37 * This function disables clock of useless peripherals when cpu starts. 38 */ 39 void esp_perip_clk_init(void); 40 41 /* Selects an external clock source (32 kHz) for RTC. 42 * Only internal use in unit test. 43 */ 44 void rtc_clk_select_rtc_slow_clk(void); 45