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b932b2dd1f
The delay_half parameter must be specified by the port to set up the timing of the software SPI. This allows the port to adjust the timing value to better suit its timing characteristics, as well as provide a more accurate printing of the baudrate.
120 lines
4.8 KiB
C
120 lines
4.8 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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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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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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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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#endif // MICROPY_PY_MACHINE_SPI
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