atsam/clock/systick-freq.c

0001 /* SPDX-License-Identifier: BSD-2-Clause */
0002
0003 /*
0004  * Copyright (c) 2016 embedded brains GmbH & Co. KG
0005  *
0006  * Redistribution and use in source and binary forms, with or without
0007  * modification, are permitted provided that the following conditions
0008  * are met:
0009  * 1. Redistributions of source code must retain the above copyright
0010  *    notice, this list of conditions and the following disclaimer.
0011  * 2. Redistributions in binary form must reproduce the above copyright
0012  *    notice, this list of conditions and the following disclaimer in the
0013  *    documentation and/or other materials provided with the distribution.
0014  *
0015  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
0016  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
0017  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
0018  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
0019  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
0020  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
0021  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
0022  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
0023  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
0024  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
0025  * POSSIBILITY OF SUCH DAMAGE.
0026  */
0027
0028 #include <bsp.h>
0029
0030 #include <chip.h>
0031
0032 uint32_t atsam_systick_frequency(void)
0033 {
0034   uint32_t mdiv = (PMC->PMC_MCKR & PMC_MCKR_MDIV_Msk) >> PMC_MCKR_MDIV_Pos;
0035   uint32_t fclk;
0036
0037   if (mdiv == 3) {
0038     fclk = BOARD_MCK * mdiv;
0039   } else {
0040     fclk = BOARD_MCK * (1 << mdiv);
0041   }
0042
0043   return fclk;
0044 }