circuitpython/ports/samd/samd_soc.c
robert-hh b4d29fd47a samd/clock_config: Set up the clock configuration.
Clock settings:
- GCLK0: 48 MHz (SAMD21) or 120 MHz(SAMD51).
- GCLK1: 32768 Hz for driving the PLL.
- GCLK2: 48 MHz for tzhe peripheral clock.
- GCLK3: 1 MHz (SAMD21) or 8 MHz (SAMD51) for the µs ticks timer.
- GCLK8: 1 kHz for WDT (SAMD21 only).

If a 32 kHz crystal is present, it will be used as clock source.  Otherwise
the DFLL48M in open-loop mode is used.

GCLK0 for SAM51 can be changed between 48 MHz and 200 MHz.  The specified
range is 96 MHz - 120 MHz.
2022-10-06 22:33:31 +11:00

114 lines
4.0 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* This file initialises the USB (tinyUSB) and USART (SERCOM). Board USART settings
* are set in 'boards/<board>/mpconfigboard.h.
*
* IMPORTANT: Please refer to "I/O Multiplexing and Considerations" chapters
* in device datasheets for I/O Pin functions and assignments.
*
* The MIT License (MIT)
*
* Copyright (c) 2019 Damien P. George
* 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 "py/runtime.h"
#include "modmachine.h"
#include "samd_soc.h"
#include "sam.h"
#include "tusb.h"
static void usb_init(void) {
// Init USB clock
#if defined(MCU_SAMD21)
GCLK->CLKCTRL.reg = GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | GCLK_CLKCTRL_ID_USB;
PM->AHBMASK.bit.USB_ = 1;
PM->APBBMASK.bit.USB_ = 1;
uint8_t alt = 6; // alt G, USB
#elif defined(MCU_SAMD51)
GCLK->PCHCTRL[USB_GCLK_ID].reg = GCLK_PCHCTRL_CHEN | GCLK_PCHCTRL_GEN_GCLK2;
while (GCLK->PCHCTRL[USB_GCLK_ID].bit.CHEN == 0) {
}
MCLK->AHBMASK.bit.USB_ = 1;
MCLK->APBBMASK.bit.USB_ = 1;
uint8_t alt = 7; // alt H, USB
#endif
// Init USB pins
PORT->Group[0].DIRSET.reg = 1 << 25 | 1 << 24;
PORT->Group[0].OUTCLR.reg = 1 << 25 | 1 << 24;
PORT->Group[0].PMUX[12].reg = alt << 4 | alt;
PORT->Group[0].PINCFG[24].reg = PORT_PINCFG_PMUXEN;
PORT->Group[0].PINCFG[25].reg = PORT_PINCFG_PMUXEN;
tusb_init();
}
// Initialize the microsecond counter on TC 0/1
void init_us_counter(void) {
#if defined(MCU_SAMD21)
PM->APBCMASK.bit.TC3_ = 1; // Enable TC3 clock
PM->APBCMASK.bit.TC4_ = 1; // Enable TC4 clock
// Select multiplexer generic clock source and enable.
GCLK->CLKCTRL.reg = GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK3 | GCLK_CLKCTRL_ID_TC4_TC5;
// Wait while it updates synchronously.
while (GCLK->STATUS.bit.SYNCBUSY) {
}
// configure the timer
TC4->COUNT32.CTRLA.bit.MODE = TC_CTRLA_MODE_COUNT32_Val;
TC4->COUNT32.CTRLA.bit.RUNSTDBY = 1;
TC4->COUNT32.CTRLA.bit.ENABLE = 1;
while (TC4->COUNT32.STATUS.bit.SYNCBUSY) {
}
TC4->COUNT32.READREQ.reg = TC_READREQ_RREQ | TC_READREQ_RCONT | 0x10;
while (TC4->COUNT32.STATUS.bit.SYNCBUSY) {
}
#elif defined(MCU_SAMD51)
MCLK->APBAMASK.bit.TC0_ = 1; // Enable TC0 clock
MCLK->APBAMASK.bit.TC1_ = 1; // Enable TC1 clock
// Peripheral channel 9 is driven by GCLK3, 8 MHz.
GCLK->PCHCTRL[TC0_GCLK_ID].reg = GCLK_PCHCTRL_GEN_GCLK3 | GCLK_PCHCTRL_CHEN;
while (GCLK->PCHCTRL[TC0_GCLK_ID].bit.CHEN == 0) {
}
// configure the timer
TC0->COUNT32.CTRLA.bit.PRESCALER = 0;
TC0->COUNT32.CTRLA.bit.MODE = TC_CTRLA_MODE_COUNT32_Val;
TC0->COUNT32.CTRLA.bit.RUNSTDBY = 1;
TC0->COUNT32.CTRLA.bit.ENABLE = 1;
while (TC0->COUNT32.SYNCBUSY.bit.ENABLE) {
}
#endif
}
void samd_init(void) {
init_clocks(get_cpu_freq());
SysTick_Config(get_cpu_freq() / 1000);
init_us_counter();
usb_init();
}