365 lines
14 KiB
C
365 lines
14 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* This file provides functions for configuring the clocks.
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2022 Robert Hammelrath
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <stdint.h>
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#include "py/runtime.h"
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#include "py/mphal.h"
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#include "samd_soc.h"
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static uint32_t cpu_freq = CPU_FREQ;
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static uint32_t peripheral_freq = DFLL48M_FREQ;
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static uint32_t dfll48m_calibration;
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int sercom_gclk_id[] = {
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SERCOM0_GCLK_ID_CORE, SERCOM1_GCLK_ID_CORE,
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SERCOM2_GCLK_ID_CORE, SERCOM3_GCLK_ID_CORE,
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SERCOM4_GCLK_ID_CORE, SERCOM5_GCLK_ID_CORE,
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#if defined(SERCOM7_GCLK_ID_CORE)
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SERCOM6_GCLK_ID_CORE, SERCOM7_GCLK_ID_CORE,
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#endif
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};
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uint32_t get_cpu_freq(void) {
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return cpu_freq;
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}
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uint32_t get_peripheral_freq(void) {
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return peripheral_freq;
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}
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void set_cpu_freq(uint32_t cpu_freq_arg) {
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// Setup GCLK0 for 48MHz as default state to keep the MCU running during config change.
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GCLK->GENCTRL[0].reg = GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL;
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while (GCLK->SYNCBUSY.bit.GENCTRL0) {
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}
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// Setup DPLL0 for 120 MHz
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// first: disable DPLL0 in case it is running
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OSCCTRL->Dpll[0].DPLLCTRLA.bit.ENABLE = 0;
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while (OSCCTRL->Dpll[0].DPLLSYNCBUSY.bit.ENABLE == 1) {
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}
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if (cpu_freq_arg > DFLL48M_FREQ) {
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cpu_freq = cpu_freq_arg;
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peripheral_freq = DFLL48M_FREQ;
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// Now configure the registers
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OSCCTRL->Dpll[0].DPLLCTRLB.reg = OSCCTRL_DPLLCTRLB_DIV(1) | OSCCTRL_DPLLCTRLB_LBYPASS |
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OSCCTRL_DPLLCTRLB_REFCLK(0) | OSCCTRL_DPLLCTRLB_WUF | OSCCTRL_DPLLCTRLB_FILTER(0x01);
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uint32_t div = cpu_freq / DPLLx_REF_FREQ;
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uint32_t frac = (cpu_freq - div * DPLLx_REF_FREQ) / (DPLLx_REF_FREQ / 32);
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OSCCTRL->Dpll[0].DPLLRATIO.reg = (frac << 16) + div - 1;
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// enable it again
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OSCCTRL->Dpll[0].DPLLCTRLA.reg = OSCCTRL_DPLLCTRLA_ENABLE | OSCCTRL_DPLLCTRLA_RUNSTDBY;
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// Per errata 2.13.1
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while (!(OSCCTRL->Dpll[0].DPLLSTATUS.bit.CLKRDY == 1)) {
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}
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// Setup GCLK0 for DPLL0 output (48 or 48-200MHz)
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GCLK->GENCTRL[0].reg = GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DPLL0;
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while (GCLK->SYNCBUSY.bit.GENCTRL0) {
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}
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// Set GCLK 2 back to 48 MHz
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GCLK->GENCTRL[2].reg = GCLK_GENCTRL_DIV(1) | GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL;
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while (GCLK->SYNCBUSY.bit.GENCTRL2) {
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}
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} else {
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int div = DFLL48M_FREQ / cpu_freq_arg;
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// Setup GCLK1 for the low freq
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GCLK->GENCTRL[2].reg = GCLK_GENCTRL_DIV(div) | GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL;
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while (GCLK->SYNCBUSY.bit.GENCTRL2) {
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}
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GCLK->GENCTRL[0].reg = GCLK_GENCTRL_DIV(div) | GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL;
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while (GCLK->SYNCBUSY.bit.GENCTRL0) {
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}
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peripheral_freq = DFLL48M_FREQ / div;
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cpu_freq = DFLL48M_FREQ / div;
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}
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if (cpu_freq >= 8000000) {
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// Setup GCLK5 for DFLL48M output (48 MHz)
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GCLK->GENCTRL[5].reg = GCLK_GENCTRL_DIV(1) | GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL;
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while (GCLK->SYNCBUSY.bit.GENCTRL5) {
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}
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} else {
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// Setup GCLK5 off if CPU Clk < 8 MHz
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GCLK->GENCTRL[5].reg = 0;
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while (GCLK->SYNCBUSY.bit.GENCTRL5) {
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}
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}
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SysTick_Config(cpu_freq / 1000);
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}
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void check_usb_recovery_mode(void) {
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#if !MICROPY_HW_XOSC32K
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mp_hal_delay_ms(500);
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// Check USB status. If not connected, switch DFLL48M back to open loop
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if (USB->DEVICE.DeviceEndpoint[0].EPCFG.reg == 0) {
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// as per Errata 2.8.3
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OSCCTRL->DFLLMUL.reg = 0;
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while (OSCCTRL->DFLLSYNC.bit.DFLLMUL == 1) {
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}
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// Set the mode to open loop mode
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OSCCTRL->DFLLCTRLB.reg = 0;
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while (OSCCTRL->DFLLSYNC.bit.DFLLCTRLB == 1) {
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}
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OSCCTRL->DFLLCTRLA.reg = OSCCTRL_DFLLCTRLA_RUNSTDBY | OSCCTRL_DFLLCTRLA_ENABLE;
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while (OSCCTRL->DFLLSYNC.bit.ENABLE == 1) {
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}
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OSCCTRL->DFLLVAL.reg = dfll48m_calibration; // Reload DFLLVAL register
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while (OSCCTRL->DFLLSYNC.bit.DFLLVAL == 1) {
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}
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// Set the mode to open loop mode
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OSCCTRL->DFLLCTRLB.reg = 0;
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while (OSCCTRL->DFLLSYNC.bit.DFLLCTRLB == 1) {
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}
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}
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#endif // MICROPY_HW_XOSC32K
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}
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// Purpose of the #defines for the clock configuration.
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//
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// The CPU clock is generated by DPLL0, which takes 32768 Hz as reference frequency,
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// supplied through GCLK1.
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//
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// DFLL48M is used for the peripheral clock, e.g. for PWM, UART, SPI, I2C.
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// DFLL48M is either free running, or controlled by the 32kHz crystal, or
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// Synchronized with the USB clock.
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//
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// GCLK1 takes it's input either from the 32kHz crystal, the internal low power
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// RC oscillator or from DFLL48M.
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//
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// #define MICROPY_HW_XOSC32K (0 | 1)
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//
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// If MICROPY_HW_XOSC32K = 1, the 32kHz crystal is used for the DFLL48M oscillator
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// and for GCLK1, feeding the CPU, unless MICROPY_HW_MCU_OSC32KULP is set.
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// In that case GCLK1 (and the CPU clock) is driven by the 32K Low power oscillator.
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// The reason for offering this option is a design flaw of the Adafruit
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// Feather boards, where the RGB Led and Debug signals interfere with the
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// crystal, causing the CPU to fail if it is driven by the crystal. The
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// peripheral devices are affected as well, but continue it's operation.
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//
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// If MICROPY_HW_XOSC32K = 0, the 32kHz signal for GCLK1 (and the CPU) is
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// created by dividing the 48MHz clock of DFLL48M.
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//
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// If MICROPY_HW_DFLL_USB_SYNC = 0, the DFLL48M oscillator is free running using
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// the pre-configured trim values. In that mode, the peripheral clock is
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// not exactly 48Mhz and has a substantional temperature drift.
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//
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// If MICROPY_HW_DFLL_USB_SYNC = 1, the DFLL48 is synchronized with the 1 kHz USB sync
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// signal. If after boot there is no USB sync withing 500ms, the configuratuion falls
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// back to a free running 48Mhz oscillator.
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//
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// In all modes, the 48MHz signal has a substantial jitter, largest when
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// MICROPY_HW_DFLL_USB_SYNC is active. That is caused by the repective
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// reference frequencies of 32kHz or 1 kHz being low. That affects most
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// PWM. Std Dev at 1kHz 0.156Hz (w. Crystal) up to 0.4 Hz (with USB sync).
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//
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// If none of the mentioned defines is set, the device uses the internal oscillators.
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void init_clocks(uint32_t cpu_freq) {
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dfll48m_calibration = 0; // please the compiler
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// SAMD51 clock settings
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//
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// GCLK0: 48MHz, source: 48 - 200 MHz from DPLL0, usage: CPU
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// GCLK1: 32kHz, source: OSCULP32K or DFLL48M, usage: ref_clk DPLL0
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// GCLK2: 1-48MHz, source:DFLL48M, usage: Peripheral devices
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// GCLK3: 16Mhz, source: DLLL48M, usage: us-counter (TC0/TC1)
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// GCLK4: 32kHz, source: XOSC32K, if crystal present, usage: DFLL48M reference
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// GCLK5: 48MHz, source: DFLL48M, usage: USB
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// DFLL48M: Reference sources:
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// - in closed loop mode: eiter XOSC32K or OSCULP32K or USB clock
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// - in open loop mode: None
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// DPLL0: 48 - 200 MHz
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// Steps to set up clocks:
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// Reset Clocks
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// Switch GCLK0 to DFLL 48MHz
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// Setup 32768 Hz source and DFLL48M in closed loop mode, if a crystal is present.
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// Setup GCLK1 to the DPLL0 Reference freq. of 32768 Hz
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// Setup GCLK1 to drive peripheral channel 1
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// Setup DPLL0 to 120MHz
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// Setup GCLK0 to 120MHz
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// Setup GCLK2 to 48MHz for Peripherals
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// Setup GCLK3 to 16MHz for TC0/TC1
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// Setup GCLK4 to 32kHz crystal, if present
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// Setup GCLK5 to 48 MHz
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// Setup GCLK0 for 48MHz as default state to keep the MCU running during config change.
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GCLK->GENCTRL[0].reg = GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL;
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while (GCLK->SYNCBUSY.bit.GENCTRL0) {
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}
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#if MICROPY_HW_XOSC32K
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// OSCILLATOR CONTROL
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// Enable the clock for RTC
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OSC32KCTRL->RTCCTRL.reg = OSC32KCTRL_RTCCTRL_RTCSEL_XOSC1K;
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// Setup XOSC32K
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OSC32KCTRL->INTFLAG.reg = OSC32KCTRL_INTFLAG_XOSC32KRDY | OSC32KCTRL_INTFLAG_XOSC32KFAIL;
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OSC32KCTRL->CFDCTRL.bit.CFDEN = 1; // Fall back to internal Osc on crystal fail
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OSC32KCTRL->XOSC32K.reg =
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OSC32KCTRL_XOSC32K_CGM_HS |
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OSC32KCTRL_XOSC32K_XTALEN |
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OSC32KCTRL_XOSC32K_EN32K |
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OSC32KCTRL_XOSC32K_EN1K |
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OSC32KCTRL_XOSC32K_RUNSTDBY |
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OSC32KCTRL_XOSC32K_STARTUP(4) |
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OSC32KCTRL_XOSC32K_ENABLE;
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// make sure osc32kcrtl is ready
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while (OSC32KCTRL->STATUS.bit.XOSC32KRDY == 0) {
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}
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#if MICROPY_HW_MCU_OSC32KULP
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// Setup GCLK1 for 32kHz ULP
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GCLK->GENCTRL[1].reg = GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_OSCULP32K;
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#else
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// Setup GCLK1 for 32kHz crystal
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GCLK->GENCTRL[1].reg = GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_XOSC32K;
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#endif
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while (GCLK->SYNCBUSY.bit.GENCTRL1) {
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}
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// Setup GCLK4 for 32kHz crystal
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GCLK->GENCTRL[4].reg = GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_XOSC32K;
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while (GCLK->SYNCBUSY.bit.GENCTRL4) {
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}
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// Set-up the DFLL48M in closed loop mode with input from the 32kHz crystal
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// Step 1: Peripheral channel 0 is driven by GCLK4 and it feeds DFLL48M
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GCLK->PCHCTRL[0].reg = GCLK_PCHCTRL_GEN_GCLK4 | GCLK_PCHCTRL_CHEN;
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while (GCLK->PCHCTRL[0].bit.CHEN == 0) {
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}
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// Step 2: Set the multiplication values. The offset of 16384 to the freq is for rounding.
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OSCCTRL->DFLLMUL.reg = OSCCTRL_DFLLMUL_MUL((DFLL48M_FREQ + DPLLx_REF_FREQ / 2) / DPLLx_REF_FREQ) |
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OSCCTRL_DFLLMUL_FSTEP(1) | OSCCTRL_DFLLMUL_CSTEP(1);
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while (OSCCTRL->DFLLSYNC.bit.DFLLMUL == 1) {
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}
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// Step 3: Set the mode to closed loop
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OSCCTRL->DFLLCTRLB.reg = OSCCTRL_DFLLCTRLB_BPLCKC | OSCCTRL_DFLLCTRLB_STABLE | OSCCTRL_DFLLCTRLB_MODE;
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while (OSCCTRL->DFLLSYNC.bit.DFLLCTRLB == 1) {
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}
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// Wait for lock fine
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while (OSCCTRL->STATUS.bit.DFLLLCKF == 0) {
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}
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// Step 4: Start the DFLL.
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OSCCTRL->DFLLCTRLA.reg = OSCCTRL_DFLLCTRLA_RUNSTDBY | OSCCTRL_DFLLCTRLA_ENABLE;
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while (OSCCTRL->DFLLSYNC.bit.ENABLE == 1) {
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}
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#else // MICROPY_HW_XOSC32K
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// Enable the clock for RTC
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OSC32KCTRL->RTCCTRL.reg = OSC32KCTRL_RTCCTRL_RTCSEL_ULP1K;
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// Derive GCLK1 from DFLL48M at DPLL0_REF_FREQ as defined in mpconfigboard.h (e.g. 32768 Hz)
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GCLK->GENCTRL[1].reg = ((DFLL48M_FREQ + DPLLx_REF_FREQ / 2) / DPLLx_REF_FREQ) << GCLK_GENCTRL_DIV_Pos
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| GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL;
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while (GCLK->SYNCBUSY.bit.GENCTRL1) {
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}
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OSCCTRL->DFLLCTRLA.bit.RUNSTDBY = 1;
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OSCCTRL->DFLLCTRLA.bit.ONDEMAND = 0;
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OSCCTRL->DFLLCTRLA.bit.ENABLE = 1;
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while (OSCCTRL->DFLLSYNC.bit.ENABLE == 1) {
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}
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#if MICROPY_HW_DFLL_USB_SYNC
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// Configure the DFLL48M for USB clock recovery.
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// Will have to switch back if no USB
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dfll48m_calibration = OSCCTRL->DFLLVAL.reg;
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// Set the Multiplication factor.
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OSCCTRL->DFLLMUL.reg = OSCCTRL_DFLLMUL_MUL(48000) |
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OSCCTRL_DFLLMUL_FSTEP(1) | OSCCTRL_DFLLMUL_CSTEP(1);
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while (OSCCTRL->DFLLSYNC.bit.DFLLMUL == 1) {
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}
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// Set the mode to closed loop USB Recovery
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OSCCTRL->DFLLCTRLB.reg = OSCCTRL_DFLLCTRLB_USBCRM | OSCCTRL_DFLLCTRLB_CCDIS | OSCCTRL_DFLLCTRLB_MODE;
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while (OSCCTRL->DFLLSYNC.bit.DFLLCTRLB == 1) {
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}
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#endif
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#endif // MICROPY_HW_XOSC32K
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// Peripheral channel 1 is driven by GCLK1 and it feeds DPLL0
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GCLK->PCHCTRL[1].reg = GCLK_PCHCTRL_GEN_GCLK1 | GCLK_PCHCTRL_CHEN;
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while (GCLK->PCHCTRL[1].bit.CHEN == 0) {
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}
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set_cpu_freq(cpu_freq);
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peripheral_freq = DFLL48M_FREQ; // To be changed if CPU_FREQ < 48M
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// Setup GCLK2 for DFLL48M output (48 MHz), may be scaled down later by calls to set_cpu_freq
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GCLK->GENCTRL[2].reg = GCLK_GENCTRL_DIV(1) | GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL;
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while (GCLK->SYNCBUSY.bit.GENCTRL2) {
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}
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// Setup GCLK3 for 16MHz, Used for TC0/1 counter
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GCLK->GENCTRL[3].reg = GCLK_GENCTRL_DIV(3) | GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL;
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while (GCLK->SYNCBUSY.bit.GENCTRL3) {
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}
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}
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void enable_sercom_clock(int id) {
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GCLK->PCHCTRL[sercom_gclk_id[id]].reg = GCLK_PCHCTRL_CHEN | GCLK_PCHCTRL_GEN_GCLK2;
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// no easy way to set the clocks, except enabling all of them
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switch (id) {
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case 0:
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MCLK->APBAMASK.bit.SERCOM0_ = 1;
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break;
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case 1:
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MCLK->APBAMASK.bit.SERCOM1_ = 1;
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break;
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case 2:
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MCLK->APBBMASK.bit.SERCOM2_ = 1;
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break;
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case 3:
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MCLK->APBBMASK.bit.SERCOM3_ = 1;
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break;
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case 4:
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MCLK->APBDMASK.bit.SERCOM4_ = 1;
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break;
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case 5:
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MCLK->APBDMASK.bit.SERCOM5_ = 1;
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break;
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#ifdef SERCOM7_GCLK_ID_CORE
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case 6:
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MCLK->APBDMASK.bit.SERCOM6_ = 1;
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break;
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case 7:
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MCLK->APBDMASK.bit.SERCOM7_ = 1;
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break;
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#endif
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}
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}
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