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mirror of https://github.com/RIOT-OS/RIOT.git synced 2024-12-29 04:50:03 +01:00
RIOT/cpu/rpx0xx/xosc.c
Marian Buschsieweke bf96c28889
cpu/rpx0xx: Update vendor header files
Generated new vendor header files from upstream SVD files using:

    ./SVDConv "$PICO_SDK_DIR"/src/rp2040/hardware_regs/rp2040.svd \
        --generate=header --fields=macro --fields=enum

Note: The missing `--fields=struct` flag resulted in the header no
      longer containing bit-fields to represent different fields
      within registers. While this would generally ease writing code,
      the RP2040 has the unpleasant feature of corrupting the
      remaining bits of the register when a write access that is not
      word-sized occurs in the memory mapped I/O area. This could
      happen e.g. when a bit field is byte-sized and byte-aligned.
2023-03-22 19:34:29 +01:00

49 lines
1.4 KiB
C

/*
* Copyright (C) 2021 Otto-von-Guericke Universität Magdeburg
*
* This file is subject to the terms and conditions of the GNU Lesser
* General Public License v2.1. See the file LICENSE in the top level
* directory for more details.
*/
/**
* @ingroup cpu_rpx0xx
* @{
*
* @file
* @brief Implementation of the crystal oscillator (XOSC)
*
* @author Marian Buschsieweke <marian.buschsieweke@ovgu.de>
* @author Fabian Hüßler <fabian.huessler@ovgu.de>
*
* @}
*/
#include <assert.h>
#include "macros/units.h"
#include "vendor/RP2040.h"
#include "io_reg.h"
static inline uint32_t _xosc_conf_sartup_delay(uint32_t f_crystal_mhz, uint32_t t_stable_ms)
{
return (((f_crystal_mhz / 1000) * t_stable_ms) + 128) / 256;
}
void xosc_start(uint32_t f_ref)
{
assert(f_ref == MHZ(12));
uint32_t delay = _xosc_conf_sartup_delay(f_ref, 1);
io_reg_write_dont_corrupt(&XOSC->STARTUP, delay << XOSC_STARTUP_DELAY_Pos,
XOSC_STARTUP_DELAY_Msk);
io_reg_write_dont_corrupt(&XOSC->CTRL, XOSC_CTRL_ENABLE_ENABLE << XOSC_CTRL_ENABLE_Pos,
XOSC_CTRL_ENABLE_Msk);
while (!(XOSC->STATUS & XOSC_STATUS_STABLE_Msk)) { }
}
void xosc_stop(void)
{
io_reg_write_dont_corrupt(&XOSC->CTRL, XOSC_CTRL_ENABLE_DISABLE << XOSC_CTRL_ENABLE_Pos,
XOSC_CTRL_ENABLE_Msk);
}