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modpybspi.c
modpybspi.c 8.53 KiB
/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2016 Damien P. George
*
* 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 <stdio.h>
#include <stdint.h>
#include <string.h>
#include "ets_sys.h"
#include "etshal.h"
#include "ets_alt_task.h"
#include "py/runtime.h"
#include "py/stream.h"
#include "py/mphal.h"
typedef struct _pyb_spi_obj_t {
mp_obj_base_t base;
uint32_t baudrate;
uint8_t polarity;
uint8_t phase;
mp_hal_pin_obj_t sck;
mp_hal_pin_obj_t mosi;
mp_hal_pin_obj_t miso;
} pyb_spi_obj_t;
STATIC void mp_hal_spi_transfer(pyb_spi_obj_t *self, size_t src_len, const uint8_t *src_buf, size_t dest_len, uint8_t *dest_buf) {
// only MSB transfer is implemented
uint32_t delay_half = 500000 / self->baudrate + 1;
for (size_t i = 0; i < src_len || i < dest_len; ++i) {
uint8_t data_out;
if (src_len == 1) {
data_out = src_buf[0];
} else {
data_out = src_buf[i];
}
uint8_t data_in = 0;
for (int j = 0; j < 8; ++j, data_out <<= 1) {
mp_hal_pin_write(self->mosi, (data_out >> 7) & 1);
if (self->phase == 0) {
ets_delay_us(delay_half);
mp_hal_pin_write(self->sck, 1 - self->polarity);
} else {
mp_hal_pin_write(self->sck, 1 - self->polarity);
ets_delay_us(delay_half);
}
data_in = (data_in << 1) | mp_hal_pin_read(self->miso);
if (self->phase == 0) { ets_delay_us(delay_half);
mp_hal_pin_write(self->sck, self->polarity);
} else {
mp_hal_pin_write(self->sck, self->polarity);
ets_delay_us(delay_half);
}
}
if (dest_len != 0) {
dest_buf[i] = data_in;
}
// make sure pending tasks have a chance to run
ets_loop_iter();
}
}
/******************************************************************************/
// MicroPython bindings for SPI
STATIC void pyb_spi_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
pyb_spi_obj_t *self = MP_OBJ_TO_PTR(self_in);
mp_printf(print, "SPI(baudrate=%u, polarity=%u, phase=%u, sck=%u, mosi=%u, miso=%u)",
self->baudrate, self->polarity, self->phase, self->sck, self->mosi, self->miso);
}
STATIC void pyb_spi_init_helper(pyb_spi_obj_t *self, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_baudrate, ARG_polarity, ARG_phase, ARG_sck, ARG_mosi, ARG_miso };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_baudrate, MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_polarity, MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_phase, MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_sck, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_mosi, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
{ MP_QSTR_miso, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_obj = MP_OBJ_NULL} },
};
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
if (args[ARG_baudrate].u_int != -1) {
self->baudrate = args[ARG_baudrate].u_int;
}
if (args[ARG_polarity].u_int != -1) {
self->polarity = args[ARG_polarity].u_int;
}
if (args[ARG_phase].u_int != -1) {
self->phase = args[ARG_phase].u_int;
}
if (args[ARG_sck].u_obj != MP_OBJ_NULL) {
self->sck = mp_hal_get_pin_obj(args[ARG_sck].u_obj);
}
if (args[ARG_mosi].u_obj != MP_OBJ_NULL) {
self->mosi = mp_hal_get_pin_obj(args[ARG_mosi].u_obj);
}
if (args[ARG_miso].u_obj != MP_OBJ_NULL) {
self->miso = mp_hal_get_pin_obj(args[ARG_miso].u_obj);
}
// configure pins
mp_hal_pin_write(self->sck, self->polarity);
mp_hal_pin_output(self->sck);
mp_hal_pin_output(self->mosi);
mp_hal_pin_input(self->miso);
}
mp_obj_t pyb_spi_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
mp_arg_check_num(n_args, n_kw, 0, MP_OBJ_FUN_ARGS_MAX, true);
pyb_spi_obj_t *self = m_new_obj(pyb_spi_obj_t);
self->base.type = &pyb_spi_type;
// set defaults
self->baudrate = 500000;
self->polarity = 0; self->phase = 0;
self->sck = 14;
self->mosi = 13;
self->miso = 12;
mp_map_t kw_args;
mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
pyb_spi_init_helper(self, n_args, args, &kw_args);
return MP_OBJ_FROM_PTR(self);
}
STATIC mp_obj_t pyb_spi_init(size_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
pyb_spi_init_helper(args[0], n_args - 1, args + 1, kw_args);
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_KW(pyb_spi_init_obj, 1, pyb_spi_init);
STATIC mp_obj_t pyb_spi_read(size_t n_args, const mp_obj_t *args) {
pyb_spi_obj_t *self = MP_OBJ_TO_PTR(args[0]);
uint8_t write_byte = 0;
if (n_args == 3) {
write_byte = mp_obj_get_int(args[2]);
}
vstr_t vstr;
vstr_init_len(&vstr, mp_obj_get_int(args[1]));
mp_hal_spi_transfer(self, 1, &write_byte, vstr.len, (uint8_t*)vstr.buf);
return mp_obj_new_str_from_vstr(&mp_type_bytes, &vstr);
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_spi_read_obj, 2, 3, pyb_spi_read);
STATIC mp_obj_t pyb_spi_readinto(size_t n_args, const mp_obj_t *args) {
pyb_spi_obj_t *self = MP_OBJ_TO_PTR(args[0]);
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(args[1], &bufinfo, MP_BUFFER_WRITE);
uint8_t write_byte = 0;
if (n_args == 3) {
write_byte = mp_obj_get_int(args[2]);
}
mp_hal_spi_transfer(self, 1, &write_byte, bufinfo.len, (uint8_t*)bufinfo.buf);
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_spi_readinto_obj, 2, 3, pyb_spi_readinto);
STATIC mp_obj_t pyb_spi_write(mp_obj_t self_in, mp_obj_t wr_buf_in) {
pyb_spi_obj_t *self = MP_OBJ_TO_PTR(self_in);
mp_buffer_info_t src_buf;
mp_get_buffer_raise(wr_buf_in, &src_buf, MP_BUFFER_READ);
mp_hal_spi_transfer(self, src_buf.len, (const uint8_t*)src_buf.buf, 0, NULL);
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_2(pyb_spi_write_obj, pyb_spi_write);
STATIC mp_obj_t pyb_spi_write_readinto(mp_obj_t self_in, mp_obj_t wr_buf_in, mp_obj_t rd_buf_in) {
pyb_spi_obj_t *self = MP_OBJ_TO_PTR(self_in);
mp_buffer_info_t src_buf;
mp_get_buffer_raise(wr_buf_in, &src_buf, MP_BUFFER_READ);
mp_buffer_info_t dest_buf;
mp_get_buffer_raise(rd_buf_in, &dest_buf, MP_BUFFER_WRITE);
if (src_buf.len != dest_buf.len) {
nlr_raise(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "buffers must be the same length"));
}
mp_hal_spi_transfer(self, src_buf.len, (const uint8_t*)src_buf.buf, dest_buf.len, (uint8_t*)dest_buf.buf);
return mp_const_none;
}
MP_DEFINE_CONST_FUN_OBJ_3(pyb_spi_write_readinto_obj, pyb_spi_write_readinto);
STATIC const mp_rom_map_elem_t pyb_spi_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&pyb_spi_init_obj) },
{ MP_ROM_QSTR(MP_QSTR_read), MP_ROM_PTR(&pyb_spi_read_obj) },
{ MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&pyb_spi_readinto_obj) },
{ MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&pyb_spi_write_obj) }, { MP_ROM_QSTR(MP_QSTR_write_readinto), MP_ROM_PTR(&pyb_spi_write_readinto_obj) },
};
STATIC MP_DEFINE_CONST_DICT(pyb_spi_locals_dict, pyb_spi_locals_dict_table);
const mp_obj_type_t pyb_spi_type = {
{ &mp_type_type },
.name = MP_QSTR_SoftSPI,
.print = pyb_spi_print,
.make_new = pyb_spi_make_new,
.locals_dict = (mp_obj_dict_t*)&pyb_spi_locals_dict,
};