micropython/ports/samd/clock_config.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* This file provides functions for configuring the clocks.
*
* The MIT License (MIT)
*
* Copyright (c) 2022 Robert Hammelrath
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include <stdint.h>
#include "py/runtime.h"
#include "samd_soc.h"
static uint32_t cpu_freq = CPU_FREQ;
static uint32_t apb_freq = APB_FREQ;
#if defined(MCU_SAMD21)
int sercom_gclk_id[] = {
GCLK_CLKCTRL_ID_SERCOM0_CORE, GCLK_CLKCTRL_ID_SERCOM1_CORE,
GCLK_CLKCTRL_ID_SERCOM2_CORE, GCLK_CLKCTRL_ID_SERCOM3_CORE,
GCLK_CLKCTRL_ID_SERCOM4_CORE, GCLK_CLKCTRL_ID_SERCOM5_CORE
};
#elif defined(MCU_SAMD51)
int sercom_gclk_id[] = {
SERCOM0_GCLK_ID_CORE, SERCOM1_GCLK_ID_CORE,
SERCOM2_GCLK_ID_CORE, SERCOM3_GCLK_ID_CORE,
SERCOM4_GCLK_ID_CORE, SERCOM5_GCLK_ID_CORE,
#if defined(SERCOM7_GCLK_ID_CORE)
SERCOM6_GCLK_ID_CORE, SERCOM7_GCLK_ID_CORE,
#endif
};
#endif
uint32_t get_cpu_freq(void) {
return cpu_freq;
}
uint32_t get_apb_freq(void) {
return apb_freq;
}
#if defined(MCU_SAMD21)
void set_cpu_freq(uint32_t cpu_freq_arg) {
cpu_freq = cpu_freq_arg;
}
#elif defined(MCU_SAMD51)
void set_cpu_freq(uint32_t cpu_freq_arg) {
cpu_freq = cpu_freq_arg;
// Setup GCLK0 for 48MHz as default state to keep the MCU running during config change.
GCLK->GENCTRL[0].reg = GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL;
while (GCLK->SYNCBUSY.bit.GENCTRL0) {
}
// Setup DPLL0 for 120 MHz
// first: disable DPLL0 in case it is running
OSCCTRL->Dpll[0].DPLLCTRLA.bit.ENABLE = 0;
while (OSCCTRL->Dpll[0].DPLLSYNCBUSY.bit.ENABLE == 1) {
}
// Now configure the registers
OSCCTRL->Dpll[0].DPLLCTRLB.reg = OSCCTRL_DPLLCTRLB_DIV(1) | OSCCTRL_DPLLCTRLB_LBYPASS |
OSCCTRL_DPLLCTRLB_REFCLK(0) | OSCCTRL_DPLLCTRLB_WUF | OSCCTRL_DPLLCTRLB_FILTER(0x01);
uint32_t div = cpu_freq / DPLLx_REF_FREQ;
uint32_t frac = (cpu_freq - div * DPLLx_REF_FREQ) / (DPLLx_REF_FREQ / 32);
OSCCTRL->Dpll[0].DPLLRATIO.reg = (frac << 16) + div - 1;
// enable it again
OSCCTRL->Dpll[0].DPLLCTRLA.reg = OSCCTRL_DPLLCTRLA_ENABLE | OSCCTRL_DPLLCTRLA_RUNSTDBY;
// Per errata 2.13.1
while (!(OSCCTRL->Dpll[0].DPLLSTATUS.bit.CLKRDY == 1)) {
}
// Setup GCLK0 for DPLL0 output (48 or 48-200MHz)
GCLK->GENCTRL[0].reg = GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DPLL0;
while (GCLK->SYNCBUSY.bit.GENCTRL0) {
}
}
#endif
void init_clocks(uint32_t cpu_freq) {
#if defined(MCU_SAMD21)
// SAMD21 Clock settings
// GCLK0: 48MHz from DFLL open loop mode or closed loop mode from 32k Crystal
// GCLK1: 32768 Hz from 32K ULP or 32k Crystal
// GCLK2: 48MHz from DFLL for Peripherals
// GCLK3: 1Mhz for the us-counter (TC3/TC4)
// GCLK8: 1kHz clock for WDT
NVMCTRL->CTRLB.bit.MANW = 1; // errata "Spurious Writes"
NVMCTRL->CTRLB.bit.RWS = 1; // 1 read wait state for 48MHz
#if MICROPY_HW_XOSC32K
// Set up OSC32K according datasheet 17.6.3
SYSCTRL->XOSC32K.reg = SYSCTRL_XOSC32K_STARTUP(0x3) | SYSCTRL_XOSC32K_EN32K |
SYSCTRL_XOSC32K_XTALEN;
SYSCTRL->XOSC32K.bit.ENABLE = 1;
while (SYSCTRL->PCLKSR.bit.XOSC32KRDY == 0) {
}
// Set up the DFLL48 according to the data sheet 17.6.7.1.2
// Step 1: Set up the reference clock
// Connect the OSC32K via GCLK1 to the DFLL input and for further use.
GCLK->GENDIV.reg = GCLK_GENDIV_ID(1) | GCLK_GENDIV_DIV(1);
GCLK->GENCTRL.reg = GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_XOSC32K | GCLK_GENCTRL_ID(1);
while (GCLK->STATUS.bit.SYNCBUSY) {
}
GCLK->CLKCTRL.reg = GCLK_CLKCTRL_ID_DFLL48 | GCLK_CLKCTRL_GEN_GCLK1 | GCLK_CLKCTRL_CLKEN;
// Enable access to the DFLLCTRL reg acc. to Errata 1.2.1
SYSCTRL->DFLLCTRL.reg = SYSCTRL_DFLLCTRL_ENABLE;
while (SYSCTRL->PCLKSR.bit.DFLLRDY == 0) {
}
// Step 2: Set the coarse and fine values.
// The coarse setting will be taken from the calibration data. So the value used here
// does not matter. Get the coarse value from the calib data. In case it is not set,
// set a midrange value.
uint32_t coarse = (*((uint32_t *)FUSES_DFLL48M_COARSE_CAL_ADDR) & FUSES_DFLL48M_COARSE_CAL_Msk)
>> FUSES_DFLL48M_COARSE_CAL_Pos;
if (coarse == 0x3f) {
coarse = 0x1f;
}
SYSCTRL->DFLLVAL.reg = SYSCTRL_DFLLVAL_COARSE(coarse) | SYSCTRL_DFLLVAL_FINE(512);
while (SYSCTRL->PCLKSR.bit.DFLLRDY == 0) {
}
// Step 3: Set the multiplication values. The offset of 16384 to the freq is for rounding.
SYSCTRL->DFLLMUL.reg = SYSCTRL_DFLLMUL_MUL((CPU_FREQ + 16384) / 32768) |
SYSCTRL_DFLLMUL_FSTEP(1) | SYSCTRL_DFLLMUL_CSTEP(1);
while (SYSCTRL->PCLKSR.bit.DFLLRDY == 0) {
}
// Step 4: Start the DFLL and wait for the PLL lock. We just wait for the fine lock, since
// coarse adjusting is bypassed.
SYSCTRL->DFLLCTRL.reg |= SYSCTRL_DFLLCTRL_MODE | SYSCTRL_DFLLCTRL_WAITLOCK |
SYSCTRL_DFLLCTRL_BPLCKC | SYSCTRL_DFLLCTRL_ENABLE;
while (SYSCTRL->PCLKSR.bit.DFLLLCKF == 0) {
}
#else // MICROPY_HW_XOSC32K
// Enable DFLL48M
SYSCTRL->DFLLCTRL.reg = SYSCTRL_DFLLCTRL_ENABLE;
while (!SYSCTRL->PCLKSR.bit.DFLLRDY) {
}
SYSCTRL->DFLLMUL.reg = SYSCTRL_DFLLMUL_CSTEP(1) | SYSCTRL_DFLLMUL_FSTEP(1)
| SYSCTRL_DFLLMUL_MUL(48000);
uint32_t coarse = (*((uint32_t *)FUSES_DFLL48M_COARSE_CAL_ADDR) & FUSES_DFLL48M_COARSE_CAL_Msk)
>> FUSES_DFLL48M_COARSE_CAL_Pos;
if (coarse == 0x3f) {
coarse = 0x1f;
}
SYSCTRL->DFLLVAL.reg = SYSCTRL_DFLLVAL_COARSE(coarse) | SYSCTRL_DFLLVAL_FINE(512);
SYSCTRL->DFLLCTRL.reg = SYSCTRL_DFLLCTRL_CCDIS | SYSCTRL_DFLLCTRL_USBCRM
| SYSCTRL_DFLLCTRL_MODE | SYSCTRL_DFLLCTRL_ENABLE;
while (!SYSCTRL->PCLKSR.bit.DFLLRDY) {
}
// Enable 32768 Hz on GCLK1 for consistency
GCLK->GENDIV.reg = GCLK_GENDIV_ID(1) | GCLK_GENDIV_DIV(48016384 / 32768);
GCLK->GENCTRL.reg = GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL48M | GCLK_GENCTRL_ID(1);
while (GCLK->STATUS.bit.SYNCBUSY) {
}
#endif // MICROPY_HW_XOSC32K
// Enable GCLK output: 48M on both CCLK0 and GCLK2
GCLK->GENDIV.reg = GCLK_GENDIV_ID(0) | GCLK_GENDIV_DIV(1);
GCLK->GENCTRL.reg = GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL48M | GCLK_GENCTRL_ID(0);
while (GCLK->STATUS.bit.SYNCBUSY) {
}
GCLK->GENDIV.reg = GCLK_GENDIV_ID(2) | GCLK_GENDIV_DIV(1);
GCLK->GENCTRL.reg = GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL48M | GCLK_GENCTRL_ID(2);
while (GCLK->STATUS.bit.SYNCBUSY) {
}
// Enable GCLK output: 1MHz on GCLK3 for TC3
GCLK->GENDIV.reg = GCLK_GENDIV_ID(3) | GCLK_GENDIV_DIV(48);
GCLK->GENCTRL.reg = GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL48M | GCLK_GENCTRL_ID(3);
while (GCLK->STATUS.bit.SYNCBUSY) {
}
// Set GCLK8 to 1 kHz.
GCLK->GENDIV.reg = GCLK_GENDIV_ID(8) | GCLK_GENDIV_DIV(32);
GCLK->GENCTRL.reg = GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_OSCULP32K | GCLK_GENCTRL_ID(8);
while (GCLK->STATUS.bit.SYNCBUSY) {
}
#elif defined(MCU_SAMD51)
// SAMD51 clock settings
// GCLK0: 48MHz from DFLL48M or 48 - 200 MHz from DPLL0 (SAMD51)
// GCLK1: DPLLx_REF_FREQ 32768 Hz from 32KULP or 32k Crystal
// GCLK2: 48MHz from DFLL48M for Peripheral devices
// GCLK3: 16Mhz for the us-counter (TC0/TC1)
// DPLL0: 48 - 200 MHz
// Steps to set up clocks:
// Reset Clocks
// Switch GCLK0 to DFLL 48MHz
// Setup 32768 Hz source and DFLL48M in closed loop mode, if a crystal is present.
// Setup GCLK1 to the DPLL0 Reference freq. of 32768 Hz
// Setup GCLK1 to drive peripheral channel 1
// Setup DPLL0 to 120MHz
// Setup GCLK0 to 120MHz
// Setup GCLK2 to 48MHz for Peripherals
// Setup GCLK3 to 8MHz for TC0/TC1
// Setup GCLK0 for 48MHz as default state to keep the MCU running during config change.
GCLK->GENCTRL[0].reg = GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL;
while (GCLK->SYNCBUSY.bit.GENCTRL0) {
}
#if MICROPY_HW_XOSC32K
// OSCILLATOR CONTROL
// Setup XOSC32K
OSC32KCTRL->INTFLAG.reg = OSC32KCTRL_INTFLAG_XOSC32KRDY | OSC32KCTRL_INTFLAG_XOSC32KFAIL;
OSC32KCTRL->XOSC32K.bit.CGM = OSC32KCTRL_XOSC32K_CGM_HS_Val;
OSC32KCTRL->XOSC32K.bit.XTALEN = 1; // 0: Generator 1: Crystal
OSC32KCTRL->XOSC32K.bit.EN32K = 1;
OSC32KCTRL->XOSC32K.bit.ONDEMAND = 0;
OSC32KCTRL->XOSC32K.bit.RUNSTDBY = 1;
OSC32KCTRL->XOSC32K.bit.STARTUP = 4;
OSC32KCTRL->CFDCTRL.bit.CFDEN = 1; // Fall back to internal Osc on crystal fail
OSC32KCTRL->XOSC32K.bit.ENABLE = 1;
// make sure osc32kcrtl is ready
while (OSC32KCTRL->STATUS.bit.XOSC32KRDY == 0) {
}
// Setup GCLK1 for 32kHz crystal
GCLK->GENCTRL[1].reg = GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_XOSC32K;
while (GCLK->SYNCBUSY.bit.GENCTRL1) {
}
// Set-up the DFLL48M in closed loop mode with input from the 32kHz crystal
// Step 1: Peripheral channel 0 is driven by GCLK1 and it feeds DFLL48M
GCLK->PCHCTRL[0].reg = GCLK_PCHCTRL_GEN_GCLK1 | GCLK_PCHCTRL_CHEN;
while (GCLK->PCHCTRL[0].bit.CHEN == 0) {
}
// Step 2: Set the multiplication values. The offset of 16384 to the freq is for rounding.
OSCCTRL->DFLLMUL.reg = OSCCTRL_DFLLMUL_MUL((APB_FREQ + DPLLx_REF_FREQ / 2) / DPLLx_REF_FREQ) |
OSCCTRL_DFLLMUL_FSTEP(1) | OSCCTRL_DFLLMUL_CSTEP(1);
while (OSCCTRL->DFLLSYNC.bit.DFLLMUL == 1) {
}
// Step 3: Set the mode to closed loop
OSCCTRL->DFLLCTRLB.reg = OSCCTRL_DFLLCTRLB_BPLCKC | OSCCTRL_DFLLCTRLB_MODE;
while (OSCCTRL->DFLLSYNC.bit.DFLLCTRLB == 1) {
}
// Wait for lock fine
while (OSCCTRL->STATUS.bit.DFLLLCKF == 0) {
}
// Step 4: Start the DFLL.
OSCCTRL->DFLLCTRLA.reg = OSCCTRL_DFLLCTRLA_RUNSTDBY | OSCCTRL_DFLLCTRLA_ENABLE;
while (OSCCTRL->DFLLSYNC.bit.ENABLE == 1) {
}
#else // MICROPY_HW_XOSC32K
// Set GCLK1 to DPLL0_REF_FREQ as defined in mpconfigboard.h (e.g. 32768 Hz)
GCLK->GENCTRL[1].reg = ((APB_FREQ + DPLLx_REF_FREQ / 2) / DPLLx_REF_FREQ) << GCLK_GENCTRL_DIV_Pos
| GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL;
while (GCLK->SYNCBUSY.bit.GENCTRL1) {
}
#endif // MICROPY_HW_XOSC32K
// Peripheral channel 1 is driven by GCLK1 and it feeds DPLL0
GCLK->PCHCTRL[1].reg = GCLK_PCHCTRL_GEN_GCLK1 | GCLK_PCHCTRL_CHEN;
while (GCLK->PCHCTRL[1].bit.CHEN == 0) {
}
set_cpu_freq(cpu_freq);
apb_freq = APB_FREQ; // To be changed if CPU_FREQ < 48M
// Setup GCLK2 for DPLL1 output (48 MHz)
GCLK->GENCTRL[2].reg = GCLK_GENCTRL_DIV(1) | GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL;
while (GCLK->SYNCBUSY.bit.GENCTRL2) {
}
// Setup GCLK3 for 8MHz, Used for TC0/1 counter
GCLK->GENCTRL[3].reg = GCLK_GENCTRL_DIV(6) | GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL;
while (GCLK->SYNCBUSY.bit.GENCTRL3) {
}
#endif // defined(MCU_SAMD51)
}
void enable_sercom_clock(int id) {
// Next: Set up the clocks
#if defined(MCU_SAMD21)
// Enable synchronous clock. The bits are nicely arranged
PM->APBCMASK.reg |= 0x04 << id;
// Select multiplexer generic clock source and enable.
GCLK->CLKCTRL.reg = GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK2 | sercom_gclk_id[id];
// Wait while it updates synchronously.
while (GCLK->STATUS.bit.SYNCBUSY) {
}
#elif defined(MCU_SAMD51)
GCLK->PCHCTRL[sercom_gclk_id[id]].reg = GCLK_PCHCTRL_CHEN | GCLK_PCHCTRL_GEN_GCLK2;
// no easy way to set the clocks, except enabling all of them
switch (id) {
case 0:
MCLK->APBAMASK.bit.SERCOM0_ = 1;
break;
case 1:
MCLK->APBAMASK.bit.SERCOM1_ = 1;
break;
case 2:
MCLK->APBBMASK.bit.SERCOM2_ = 1;
break;
case 3:
MCLK->APBBMASK.bit.SERCOM3_ = 1;
break;
case 4:
MCLK->APBDMASK.bit.SERCOM4_ = 1;
break;
case 5:
MCLK->APBDMASK.bit.SERCOM5_ = 1;
break;
#ifdef SERCOM7_GCLK_ID_CORE
case 6:
MCLK->APBDMASK.bit.SERCOM6_ = 1;
break;
case 7:
MCLK->APBDMASK.bit.SERCOM7_ = 1;
break;
#endif
}
#endif
}