![Damien George](/assets/img/avatar_default.png)
So long as a port defines relevant mp_hal_pin_xxx functions (and delay) it can make use of this software SPI class without the need for additional code.
346 lines
14 KiB
C
346 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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* The MIT License (MIT)
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*
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* Copyright (c) 2016 Damien P. George
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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 <stdio.h>
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#include <string.h>
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#include "py/runtime.h"
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#include "extmod/machine_spi.h"
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#if MICROPY_PY_MACHINE_SPI
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// if a port didn't define MSB/LSB constants then provide them
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#ifndef MICROPY_PY_MACHINE_SPI_MSB
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#define MICROPY_PY_MACHINE_SPI_MSB (0)
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#define MICROPY_PY_MACHINE_SPI_LSB (1)
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#endif
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void mp_machine_soft_spi_transfer(mp_obj_base_t *self_in, size_t len, const uint8_t *src, uint8_t *dest) {
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mp_machine_soft_spi_obj_t *self = (mp_machine_soft_spi_obj_t*)self_in;
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uint32_t delay_half = self->delay_half;
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// only MSB transfer is implemented
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// If a port defines MICROPY_PY_MACHINE_SPI_MIN_DELAY, and the configured
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// delay_half is equal to this value, then the software SPI implementation
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// will run as fast as possible, limited only by CPU speed and GPIO time.
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#ifdef MICROPY_PY_MACHINE_SPI_MIN_DELAY
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if (delay_half == MICROPY_PY_MACHINE_SPI_MIN_DELAY) {
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for (size_t i = 0; i < len; ++i) {
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uint8_t data_out = src[i];
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uint8_t data_in = 0;
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for (int j = 0; j < 8; ++j, data_out <<= 1) {
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mp_hal_pin_write(self->mosi, (data_out >> 7) & 1);
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mp_hal_pin_write(self->sck, 1 - self->polarity);
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data_in = (data_in << 1) | mp_hal_pin_read(self->miso);
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mp_hal_pin_write(self->sck, self->polarity);
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}
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if (dest != NULL) {
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dest[i] = data_in;
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}
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}
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return;
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}
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#endif
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for (size_t i = 0; i < len; ++i) {
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uint8_t data_out = src[i];
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uint8_t data_in = 0;
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for (int j = 0; j < 8; ++j, data_out <<= 1) {
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mp_hal_pin_write(self->mosi, (data_out >> 7) & 1);
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if (self->phase == 0) {
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mp_hal_delay_us_fast(delay_half);
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mp_hal_pin_write(self->sck, 1 - self->polarity);
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} else {
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mp_hal_pin_write(self->sck, 1 - self->polarity);
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mp_hal_delay_us_fast(delay_half);
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}
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data_in = (data_in << 1) | mp_hal_pin_read(self->miso);
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if (self->phase == 0) {
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mp_hal_delay_us_fast(delay_half);
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mp_hal_pin_write(self->sck, self->polarity);
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} else {
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mp_hal_pin_write(self->sck, self->polarity);
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mp_hal_delay_us_fast(delay_half);
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}
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}
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if (dest != NULL) {
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dest[i] = data_in;
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}
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// Some ports need a regular callback, but probably we don't need
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// to do this every byte, or even at all.
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#ifdef MICROPY_EVENT_POLL_HOOK
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MICROPY_EVENT_POLL_HOOK;
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#endif
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}
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}
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/******************************************************************************/
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// MicroPython bindings for generic machine.SPI
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STATIC mp_obj_t mp_machine_soft_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args);
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mp_obj_t mp_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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// check the id argument, if given
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if (n_args > 0) {
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if (args[0] != MP_OBJ_NEW_SMALL_INT(-1)) {
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#if defined(MICROPY_PY_MACHINE_SPI_MAKE_NEW)
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// dispatch to port-specific constructor
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extern mp_obj_t MICROPY_PY_MACHINE_SPI_MAKE_NEW(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args);
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return MICROPY_PY_MACHINE_SPI_MAKE_NEW(type, n_args, n_kw, args);
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#else
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mp_raise_ValueError("invalid SPI peripheral");
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#endif
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}
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--n_args;
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++args;
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}
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// software SPI
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return mp_machine_soft_spi_make_new(type, n_args, n_kw, args);
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}
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STATIC mp_obj_t machine_spi_init(size_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
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mp_obj_base_t *s = (mp_obj_base_t*)MP_OBJ_TO_PTR(args[0]);
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mp_machine_spi_p_t *spi_p = (mp_machine_spi_p_t*)s->type->protocol;
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spi_p->init(s, n_args - 1, args + 1, kw_args);
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return mp_const_none;
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_KW(machine_spi_init_obj, 1, machine_spi_init);
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STATIC mp_obj_t machine_spi_deinit(mp_obj_t self) {
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mp_obj_base_t *s = (mp_obj_base_t*)MP_OBJ_TO_PTR(self);
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mp_machine_spi_p_t *spi_p = (mp_machine_spi_p_t*)s->type->protocol;
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if (spi_p->deinit != NULL) {
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spi_p->deinit(s);
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}
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return mp_const_none;
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}
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STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_spi_deinit_obj, machine_spi_deinit);
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STATIC void mp_machine_spi_transfer(mp_obj_t self, size_t len, const void *src, void *dest) {
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mp_obj_base_t *s = (mp_obj_base_t*)MP_OBJ_TO_PTR(self);
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mp_machine_spi_p_t *spi_p = (mp_machine_spi_p_t*)s->type->protocol;
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spi_p->transfer(s, len, src, dest);
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}
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STATIC mp_obj_t mp_machine_spi_read(size_t n_args, const mp_obj_t *args) {
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vstr_t vstr;
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vstr_init_len(&vstr, mp_obj_get_int(args[1]));
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memset(vstr.buf, n_args == 3 ? mp_obj_get_int(args[2]) : 0, vstr.len);
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mp_machine_spi_transfer(args[0], vstr.len, vstr.buf, vstr.buf);
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return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
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}
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MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_machine_spi_read_obj, 2, 3, mp_machine_spi_read);
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STATIC mp_obj_t mp_machine_spi_readinto(size_t n_args, const mp_obj_t *args) {
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mp_buffer_info_t bufinfo;
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mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_WRITE);
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memset(bufinfo.buf, n_args == 3 ? mp_obj_get_int(args[2]) : 0, bufinfo.len);
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mp_machine_spi_transfer(args[0], bufinfo.len, bufinfo.buf, bufinfo.buf);
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return mp_const_none;
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}
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MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(mp_machine_spi_readinto_obj, 2, 3, mp_machine_spi_readinto);
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STATIC mp_obj_t mp_machine_spi_write(mp_obj_t self, mp_obj_t wr_buf) {
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mp_buffer_info_t src;
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mp_get_buffer_raise(wr_buf, &src, MP_BUFFER_READ);
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mp_machine_spi_transfer(self, src.len, (const uint8_t*)src.buf, NULL);
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return mp_const_none;
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}
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MP_DEFINE_CONST_FUN_OBJ_2(mp_machine_spi_write_obj, mp_machine_spi_write);
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STATIC mp_obj_t mp_machine_spi_write_readinto(mp_obj_t self, mp_obj_t wr_buf, mp_obj_t rd_buf) {
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mp_buffer_info_t src;
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mp_get_buffer_raise(wr_buf, &src, MP_BUFFER_READ);
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mp_buffer_info_t dest;
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mp_get_buffer_raise(rd_buf, &dest, MP_BUFFER_WRITE);
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if (src.len != dest.len) {
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mp_raise_ValueError("buffers must be the same length");
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}
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mp_machine_spi_transfer(self, src.len, src.buf, dest.buf);
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return mp_const_none;
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}
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MP_DEFINE_CONST_FUN_OBJ_3(mp_machine_spi_write_readinto_obj, mp_machine_spi_write_readinto);
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STATIC const mp_rom_map_elem_t machine_spi_locals_dict_table[] = {
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{ MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&machine_spi_init_obj) },
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{ MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&machine_spi_deinit_obj) },
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{ MP_ROM_QSTR(MP_QSTR_read), MP_ROM_PTR(&mp_machine_spi_read_obj) },
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{ MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&mp_machine_spi_readinto_obj) },
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{ MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&mp_machine_spi_write_obj) },
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{ MP_ROM_QSTR(MP_QSTR_write_readinto), MP_ROM_PTR(&mp_machine_spi_write_readinto_obj) },
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{ MP_ROM_QSTR(MP_QSTR_MSB), MP_ROM_INT(MICROPY_PY_MACHINE_SPI_MSB) },
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{ MP_ROM_QSTR(MP_QSTR_LSB), MP_ROM_INT(MICROPY_PY_MACHINE_SPI_LSB) },
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};
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MP_DEFINE_CONST_DICT(mp_machine_spi_locals_dict, machine_spi_locals_dict_table);
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/******************************************************************************/
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// Implementation of soft SPI
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STATIC uint32_t baudrate_from_delay_half(uint32_t delay_half) {
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#ifdef MICROPY_PY_MACHINE_SPI_MIN_DELAY
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if (delay_half == MICROPY_PY_MACHINE_SPI_MIN_DELAY) {
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return MICROPY_PY_MACHINE_SPI_MAX_BAUDRATE;
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} else
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#endif
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{
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return 500000 / delay_half;
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}
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}
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STATIC uint32_t baudrate_to_delay_half(uint32_t baudrate) {
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#ifdef MICROPY_PY_MACHINE_SPI_MIN_DELAY
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if (baudrate >= MICROPY_PY_MACHINE_SPI_MAX_BAUDRATE) {
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return MICROPY_PY_MACHINE_SPI_MIN_DELAY;
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} else
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#endif
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{
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uint32_t delay_half = 500000 / baudrate;
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// round delay_half up so that: actual_baudrate <= requested_baudrate
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if (500000 % baudrate != 0) {
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delay_half += 1;
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}
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return delay_half;
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}
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}
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STATIC void mp_machine_soft_spi_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
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mp_machine_soft_spi_obj_t *self = MP_OBJ_TO_PTR(self_in);
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mp_printf(print, "SoftSPI(baudrate=%u, polarity=%u, phase=%u,"
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" sck=" MP_HAL_PIN_FMT ", mosi=" MP_HAL_PIN_FMT ", miso=" MP_HAL_PIN_FMT ")",
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baudrate_from_delay_half(self->delay_half), self->polarity, self->phase,
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mp_hal_pin_name(self->sck), mp_hal_pin_name(self->mosi), mp_hal_pin_name(self->miso));
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}
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STATIC mp_obj_t mp_machine_soft_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
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enum { ARG_baudrate, ARG_polarity, ARG_phase, ARG_bits, ARG_firstbit, 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 = 500000} },
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{ MP_QSTR_polarity, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
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{ MP_QSTR_phase, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 0} },
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{ MP_QSTR_bits, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = 8} },
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{ MP_QSTR_firstbit, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = MICROPY_PY_MACHINE_SPI_MSB} },
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{ MP_QSTR_sck, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
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{ MP_QSTR_mosi, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
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{ MP_QSTR_miso, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
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};
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mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
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mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
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// create new object
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mp_machine_soft_spi_obj_t *self = m_new_obj(mp_machine_soft_spi_obj_t);
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self->base.type = &mp_machine_soft_spi_type;
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// set parameters
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self->delay_half = baudrate_to_delay_half(args[ARG_baudrate].u_int);
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self->polarity = args[ARG_polarity].u_int;
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self->phase = args[ARG_phase].u_int;
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if (args[ARG_bits].u_int != 8) {
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mp_raise_ValueError("bits must be 8");
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}
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if (args[ARG_firstbit].u_int != MICROPY_PY_MACHINE_SPI_MSB) {
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mp_raise_ValueError("firstbit must be MSB");
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}
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if (args[ARG_sck].u_obj == MP_OBJ_NULL
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|| args[ARG_mosi].u_obj == MP_OBJ_NULL
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|| args[ARG_miso].u_obj == MP_OBJ_NULL) {
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mp_raise_ValueError("must specify all of sck/mosi/miso");
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}
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self->sck = mp_hal_get_pin_obj(args[ARG_sck].u_obj);
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self->mosi = mp_hal_get_pin_obj(args[ARG_mosi].u_obj);
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self->miso = mp_hal_get_pin_obj(args[ARG_miso].u_obj);
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// configure pins
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mp_hal_pin_write(self->sck, self->polarity);
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mp_hal_pin_output(self->sck);
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mp_hal_pin_output(self->mosi);
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mp_hal_pin_input(self->miso);
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return MP_OBJ_FROM_PTR(self);
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}
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STATIC void mp_machine_soft_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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mp_machine_soft_spi_obj_t *self = (mp_machine_soft_spi_obj_t*)self_in;
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enum { ARG_baudrate, ARG_polarity, ARG_phase, 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_sck, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
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{ MP_QSTR_mosi, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
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{ MP_QSTR_miso, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
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};
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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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if (args[ARG_baudrate].u_int != -1) {
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self->delay_half = baudrate_to_delay_half(args[ARG_baudrate].u_int);
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}
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if (args[ARG_polarity].u_int != -1) {
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self->polarity = args[ARG_polarity].u_int;
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}
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if (args[ARG_phase].u_int != -1) {
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self->phase = args[ARG_phase].u_int;
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}
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if (args[ARG_sck].u_obj != MP_OBJ_NULL) {
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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_OBJ_NULL) {
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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_OBJ_NULL) {
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self->miso = mp_hal_get_pin_obj(args[ARG_miso].u_obj);
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}
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// configure pins
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mp_hal_pin_write(self->sck, self->polarity);
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mp_hal_pin_output(self->sck);
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mp_hal_pin_output(self->mosi);
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mp_hal_pin_input(self->miso);
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}
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STATIC const mp_machine_spi_p_t mp_machine_soft_spi_p = {
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.init = mp_machine_soft_spi_init,
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.deinit = NULL,
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.transfer = mp_machine_soft_spi_transfer,
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};
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const mp_obj_type_t mp_machine_soft_spi_type = {
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{ &mp_type_type },
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.name = MP_QSTR_SoftSPI,
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.print = mp_machine_soft_spi_print,
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.make_new = mp_machine_spi_make_new, // delegate to master constructor
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.protocol = &mp_machine_soft_spi_p,
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.locals_dict = (mp_obj_dict_t*)&mp_machine_spi_locals_dict,
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};
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#endif // MICROPY_PY_MACHINE_SPI
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