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fcd1788937
Applies to both SPI and I2C. The underflow caused high baudrate settings resulting in the lowest possible baudrate. The overflow resulted in erratic baudrates, not just the lowest possible.
344 lines
12 KiB
C
344 lines
12 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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* The MIT License (MIT)
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*
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* Copyright (c) 2020-2021 Damien P. George
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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 "py/runtime.h"
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#include "py/mphal.h"
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#include "extmod/machine_spi.h"
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#include "modmachine.h"
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#include "samd_soc.h"
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#include "pin_af.h"
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#include "clock_config.h"
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#define DEFAULT_SPI_BAUDRATE (1000000)
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#define DEFAULT_SPI_POLARITY (0)
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#define DEFAULT_SPI_PHASE (0)
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#define DEFAULT_SPI_BITS (8)
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#define DEFAULT_SPI_FIRSTBIT (0)
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typedef struct _machine_spi_obj_t {
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mp_obj_base_t base;
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uint8_t id;
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uint8_t polarity;
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uint8_t phase;
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uint8_t firstbit;
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uint8_t sck;
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uint8_t mosi;
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uint8_t miso;
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uint8_t new;
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uint32_t baudrate;
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sercom_pad_config_t sck_pad_config;
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sercom_pad_config_t mosi_pad_config;
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sercom_pad_config_t miso_pad_config;
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uint8_t *dest;
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size_t rxlen;
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} machine_spi_obj_t;
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extern Sercom *sercom_instance[];
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MP_REGISTER_ROOT_POINTER(void *sercom_table[SERCOM_INST_NUM]);
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void common_spi_irq_handler(int spi_id) {
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// handle Sercom IRQ RXC
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machine_spi_obj_t *self = MP_STATE_PORT(sercom_table[spi_id]);
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// Handle IRQ
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if (self != NULL) {
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Sercom *spi = sercom_instance[self->id];
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if (spi->SPI.INTFLAG.bit.RXC != 0) {
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if (self->rxlen > 0) {
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*(self->dest)++ = spi->SPI.DATA.bit.DATA;
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self->rxlen--;
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} else {
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// Just in the unlikely case there is data but no space in the buffer
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// discard the data and clear the intflag
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uint32_t temp;
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(void)temp;
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temp = spi->SPI.DATA.bit.DATA;
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}
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}
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}
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}
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STATIC void machine_spi_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
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machine_spi_obj_t *self = MP_OBJ_TO_PTR(self_in);
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mp_printf(print, "SPI(%u, baudrate=%u, firstbit=%u, polarity=%u, phase=%u, bits=8)",
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self->id, self->baudrate, self->firstbit, self->polarity, self->phase);
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}
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STATIC void machine_spi_init(mp_obj_base_t *self_in, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
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enum { ARG_baudrate, ARG_polarity, ARG_phase, ARG_firstbit,
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ARG_sck, ARG_mosi, ARG_miso};
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static const mp_arg_t allowed_args[] = {
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{ MP_QSTR_baudrate, MP_ARG_INT, {.u_int = -1} },
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{ MP_QSTR_polarity, MP_ARG_INT, {.u_int = -1} },
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{ MP_QSTR_phase, MP_ARG_INT, {.u_int = -1} },
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{ MP_QSTR_firstbit, MP_ARG_INT, {.u_int = -1} },
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{ MP_QSTR_sck, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
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{ MP_QSTR_mosi, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
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{ MP_QSTR_miso, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
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};
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machine_spi_obj_t *self = MP_OBJ_TO_PTR(self_in);
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// Parse args
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mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
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mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
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// Set baudrate if configured.
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if (args[ARG_baudrate].u_int >= 0) {
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self->baudrate = args[ARG_baudrate].u_int;
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}
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// Set polarity if configured.
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if (args[ARG_polarity].u_int >= 0) {
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self->polarity = args[ARG_polarity].u_int;
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}
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// Set phase if configured.
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if (args[ARG_phase].u_int >= 0) {
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self->phase = args[ARG_phase].u_int;
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}
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// Set firstbit if configured.
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if (args[ARG_firstbit].u_int >= 0) {
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self->firstbit = args[ARG_firstbit].u_int;
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}
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// Set SCK/MOSI/MISO pins if configured.
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if (args[ARG_sck].u_obj != mp_const_none) {
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self->sck = mp_hal_get_pin_obj(args[ARG_sck].u_obj);
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}
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if (args[ARG_mosi].u_obj != mp_const_none) {
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self->mosi = mp_hal_get_pin_obj(args[ARG_mosi].u_obj);
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}
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if (args[ARG_miso].u_obj != mp_const_none) {
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self->miso = mp_hal_get_pin_obj(args[ARG_miso].u_obj);
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}
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// Initialise the SPI peripheral if any arguments given, or it was not initialised previously.
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if (n_args > 0 || kw_args->used > 0 || self->new) {
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self->new = false;
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// Get the pad and alt-fct numbers.
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self->sck_pad_config = get_sercom_config(self->sck, self->id);
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self->mosi_pad_config = get_sercom_config(self->mosi, self->id);
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uint8_t dopo = 0;
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#if defined(MCU_SAMD21)
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if (self->mosi_pad_config.pad_nr == 0 && self->sck_pad_config.pad_nr == 1) {
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dopo = 0;
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} else if (self->mosi_pad_config.pad_nr == 2 && self->sck_pad_config.pad_nr == 3) {
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dopo = 1;
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} else if (self->mosi_pad_config.pad_nr == 3 && self->sck_pad_config.pad_nr == 1) {
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dopo = 2;
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} else if (self->mosi_pad_config.pad_nr == 0 && self->sck_pad_config.pad_nr == 3) {
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dopo = 3;
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} else {
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mp_raise_ValueError(MP_ERROR_TEXT("invalid pin for sck or mosi"));
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}
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#elif defined(MCU_SAMD51)
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if (self->mosi_pad_config.pad_nr == 0 && self->sck_pad_config.pad_nr == 1) {
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dopo = 0;
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} else if (self->mosi_pad_config.pad_nr == 3 && self->sck_pad_config.pad_nr == 1) {
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dopo = 2;
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} else {
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mp_raise_ValueError(MP_ERROR_TEXT("invalid pin for sck or mosi"));
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}
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#endif
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if (self->miso != 0xff) { // Miso may be undefined
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self->miso_pad_config = get_sercom_config(self->miso, self->id);
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mp_hal_set_pin_mux(self->miso, self->miso_pad_config.alt_fct);
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}
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// Configure the Pin mux.
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mp_hal_set_pin_mux(self->sck, self->sck_pad_config.alt_fct);
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mp_hal_set_pin_mux(self->mosi, self->mosi_pad_config.alt_fct);
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// Set up the clocks
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enable_sercom_clock(self->id);
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// Configure the SPI
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Sercom *spi = sercom_instance[self->id];
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// Reset (clear) the peripheral registers.
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while (spi->SPI.SYNCBUSY.bit.SWRST) {
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}
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spi->SPI.CTRLA.bit.SWRST = 1;
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while (spi->SPI.SYNCBUSY.bit.SWRST) {
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}
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// Set the registers
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spi->SPI.CTRLA.bit.MODE = 0x03; // SPI master mode
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spi->SPI.CTRLA.bit.CPOL = self->polarity;
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spi->SPI.CTRLA.bit.CPHA = self->phase;
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spi->SPI.CTRLA.bit.DIPO = self->miso_pad_config.pad_nr;
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spi->SPI.CTRLA.bit.DOPO = dopo;
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spi->SPI.CTRLA.bit.DORD = self->firstbit;
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// Enable receive only if miso is defined
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if (self->miso != 0xff) {
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spi->SPI.CTRLB.reg = SERCOM_SPI_CTRLB_RXEN;
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while (spi->SPI.SYNCBUSY.bit.CTRLB) {
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}
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}
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#if defined(MCU_SAMD51)
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spi->SPI.CTRLC.reg = 1; // 1 clock cycle character spacing
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#endif
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// SPI is driven by the clock of GCLK Generator 2, freq by get_peripheral_freq()
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// baud = bus_freq / (2 * baudrate) - 1
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uint32_t baud = get_peripheral_freq() / (2 * self->baudrate);
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if (baud > 0) { // Avoid underflow
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baud -= 1;
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}
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if (baud > 255) { // Avoid overflow
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baud = 255;
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}
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spi->SPI.BAUD.reg = baud; // Set Baud
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// Enable RXC interrupt only if miso is defined
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if (self->miso != 0xff) {
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#if defined(MCU_SAMD21)
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NVIC_EnableIRQ(SERCOM0_IRQn + self->id);
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#elif defined(MCU_SAMD51)
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NVIC_EnableIRQ(SERCOM0_0_IRQn + 4 * self->id + 2);
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#endif
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sercom_register_irq(self->id, &common_spi_irq_handler);
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}
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sercom_enable(spi, 1);
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}
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}
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STATIC mp_obj_t machine_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
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mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);
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// Get SPI bus.
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int spi_id = mp_obj_get_int(args[0]);
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if (spi_id < 0 || spi_id > SERCOM_INST_NUM) {
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mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("SPI(%d) doesn't exist"), spi_id);
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}
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// Create the SPI object and fill it with defaults.
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machine_spi_obj_t *self = mp_obj_malloc(machine_spi_obj_t, &machine_spi_type);
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self->id = spi_id;
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self->baudrate = DEFAULT_SPI_BAUDRATE;
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self->polarity = DEFAULT_SPI_POLARITY;
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self->phase = DEFAULT_SPI_PHASE;
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self->firstbit = DEFAULT_SPI_FIRSTBIT;
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self->mosi = 0xff; // 0xff: pin not defined (yet)
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self->miso = 0xff;
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self->sck = 0xff;
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self->new = true;
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MP_STATE_PORT(sercom_table[spi_id]) = self;
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mp_map_t kw_args;
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mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
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machine_spi_init((mp_obj_base_t *)self, n_args - 1, args + 1, &kw_args);
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return self;
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}
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STATIC void machine_sercom_deinit(mp_obj_base_t *self_in) {
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machine_spi_obj_t *self = MP_OBJ_TO_PTR(self_in);
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Sercom *spi = sercom_instance[self->id];
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// Disable interrupts (if any)
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spi->SPI.INTENCLR.reg = 0xff;
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sercom_enable(spi, 0);
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// clear table entry of spi
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MP_STATE_PORT(sercom_table[self->id]) = NULL;
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}
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void sercom_deinit_all(void) {
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for (int i = 0; i < SERCOM_INST_NUM; i++) {
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Sercom *spi = sercom_instance[i];
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spi->SPI.INTENCLR.reg = 0xff;
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sercom_register_irq(i, NULL);
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sercom_enable(spi, 0);
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MP_STATE_PORT(sercom_table[i]) = NULL;
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}
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}
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STATIC void machine_spi_transfer(mp_obj_base_t *self_in, size_t len, const uint8_t *src, uint8_t *dest) {
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machine_spi_obj_t *self = (machine_spi_obj_t *)self_in;
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Sercom *spi = sercom_instance[self->id];
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size_t txlen = len;
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// Clear the input queue, if needed
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while (dest && spi->SPI.INTFLAG.bit.RXC) {
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uint32_t temp;
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(void)temp;
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temp = spi->SPI.DATA.bit.DATA;
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}
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// Set up the irq data pointers and enable IRQ
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if (dest) {
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if (self->miso == 0xff) {
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mp_raise_ValueError(MP_ERROR_TEXT("read is not enabled"));
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}
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spi->SPI.INTENSET.bit.RXC = 1;
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self->dest = dest;
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self->rxlen = len;
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}
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// Send by polling & receive by IRQ
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while (txlen) {
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if (spi->SPI.INTFLAG.bit.DRE) {
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spi->SPI.DATA.bit.DATA = *src;
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src += 1;
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txlen--;
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}
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}
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// Receive the remaining data, if any and clear IRQ
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// Do no wait forever.
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if (dest) {
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int32_t timeout = 1000;
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while (self->rxlen > 0 && timeout) {
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timeout--;
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MICROPY_EVENT_POLL_HOOK
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}
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spi->SPI.INTENCLR.bit.RXC = 1;
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} else {
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// Wait for the data being shifted out.
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while (!spi->SPI.INTFLAG.bit.TXC) {
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}
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}
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}
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STATIC const mp_machine_spi_p_t machine_spi_p = {
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.init = machine_spi_init,
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.deinit = machine_sercom_deinit,
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.transfer = machine_spi_transfer,
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};
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MP_DEFINE_CONST_OBJ_TYPE(
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machine_spi_type,
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MP_QSTR_SPI,
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MP_TYPE_FLAG_NONE,
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make_new, machine_spi_make_new,
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print, machine_spi_print,
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protocol, &machine_spi_p,
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locals_dict, &mp_machine_spi_locals_dict
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);
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