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circuitpython/shared-module/bitbangio/SPI.c

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12 KiB

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2013, 2014 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 "py/mpconfig.h"
#include "py/obj.h"
#include "py/runtime.h"
#include "common-hal/microcontroller/Pin.h"
#include "shared-bindings/microcontroller/__init__.h"
#include "shared-bindings/digitalio/DigitalInOut.h"
#include "shared-module/bitbangio/types.h"
#include "supervisor/shared/translate.h"
#define MAX_BAUDRATE (common_hal_mcu_get_clock_frequency() / 48)
void shared_module_bitbangio_spi_construct(bitbangio_spi_obj_t *self,
const mcu_pin_obj_t * clock, const mcu_pin_obj_t * mosi,
const mcu_pin_obj_t * miso) {
digitalinout_result_t result = common_hal_digitalio_digitalinout_construct(&self->clock, clock);
if (result != DIGITALINOUT_OK) {
mp_raise_ValueError(translate("Clock pin init failed."));
}
common_hal_digitalio_digitalinout_switch_to_output(&self->clock, self->polarity == 1, DRIVE_MODE_PUSH_PULL);
if (mosi != NULL) {
result = common_hal_digitalio_digitalinout_construct(&self->mosi, mosi);
if (result != DIGITALINOUT_OK) {
common_hal_digitalio_digitalinout_deinit(&self->clock);
mp_raise_ValueError(translate("MOSI pin init failed."));
}
self->has_mosi = true;
common_hal_digitalio_digitalinout_switch_to_output(&self->mosi, false, DRIVE_MODE_PUSH_PULL);
}
if (miso != NULL) {
// Starts out as input by default, no need to change.
result = common_hal_digitalio_digitalinout_construct(&self->miso, miso);
if (result != DIGITALINOUT_OK) {
common_hal_digitalio_digitalinout_deinit(&self->clock);
if (mosi != NULL) {
common_hal_digitalio_digitalinout_deinit(&self->mosi);
}
mp_raise_ValueError(translate("MISO pin init failed."));
}
self->has_miso = true;
}
self->delay_half = 5;
self->polarity = 0;
self->phase = 0;
}
bool shared_module_bitbangio_spi_deinited(bitbangio_spi_obj_t *self) {
return common_hal_digitalio_digitalinout_deinited(&self->clock);
}
void shared_module_bitbangio_spi_deinit(bitbangio_spi_obj_t *self) {
if (shared_module_bitbangio_spi_deinited(self)) {
return;
}
common_hal_digitalio_digitalinout_deinit(&self->clock);
if (self->has_mosi) {
common_hal_digitalio_digitalinout_deinit(&self->mosi);
}
if (self->has_miso) {
common_hal_digitalio_digitalinout_deinit(&self->miso);
}
}
void shared_module_bitbangio_spi_configure(bitbangio_spi_obj_t *self,
uint32_t baudrate, uint8_t polarity, uint8_t phase, uint8_t bits) {
self->delay_half = 500000 / baudrate;
// round delay_half up so that: actual_baudrate <= requested_baudrate
if (500000 % baudrate != 0) {
self->delay_half += 1;
}
self->polarity = polarity;
self->phase = phase;
}
bool shared_module_bitbangio_spi_try_lock(bitbangio_spi_obj_t *self) {
bool success = false;
common_hal_mcu_disable_interrupts();
if (!self->locked) {
self->locked = true;
success = true;
}
common_hal_mcu_enable_interrupts();
return success;
}
bool shared_module_bitbangio_spi_has_lock(bitbangio_spi_obj_t *self) {
return self->locked;
}
void shared_module_bitbangio_spi_unlock(bitbangio_spi_obj_t *self) {
self->locked = false;
}
// Writes out the given data.
bool shared_module_bitbangio_spi_write(bitbangio_spi_obj_t *self, const uint8_t *data, size_t len) {
if (len > 0 && !self->has_mosi) {
mp_raise_ValueError(translate("Cannot write without MOSI pin."));
}
uint32_t delay_half = self->delay_half;
// only MSB transfer is implemented
// If a port defines MICROPY_PY_MACHINE_SPI_MIN_DELAY, and the configured
// delay_half is equal to this value, then the software SPI implementation
// will run as fast as possible, limited only by CPU speed and GPIO time.
#ifdef MICROPY_PY_MACHINE_SPI_MIN_DELAY
if (delay_half <= MICROPY_PY_MACHINE_SPI_MIN_DELAY) {
for (size_t i = 0; i < len; ++i) {
uint8_t data_out = data[i];
for (int j = 0; j < 8; ++j, data_out <<= 1) {
common_hal_digitalio_digitalinout_set_value(&self->mosi, (data_out >> 7) & 1);
common_hal_digitalio_digitalinout_set_value(&self->clock, 1 - self->polarity);
common_hal_digitalio_digitalinout_set_value(&self->clock, self->polarity);
}
if (dest != NULL) {
dest[i] = data_in;
}
}
return true;
}
#endif
for (size_t i = 0; i < len; ++i) {
uint8_t data_out = data[i];
for (int j = 0; j < 8; ++j, data_out <<= 1) {
common_hal_digitalio_digitalinout_set_value(&self->mosi, (data_out >> 7) & 1);
if (self->phase == 0) {
common_hal_mcu_delay_us(delay_half);
common_hal_digitalio_digitalinout_set_value(&self->clock, 1 - self->polarity);
common_hal_mcu_delay_us(delay_half);
common_hal_digitalio_digitalinout_set_value(&self->clock, self->polarity);
} else {
common_hal_digitalio_digitalinout_set_value(&self->clock, 1 - self->polarity);
common_hal_mcu_delay_us(delay_half);
common_hal_digitalio_digitalinout_set_value(&self->clock, self->polarity);
common_hal_mcu_delay_us(delay_half);
}
}
// Some ports need a regular callback, but probably we don't need
// to do this every byte, or even at all.
#ifdef MICROPY_EVENT_POLL_HOOK
MICROPY_EVENT_POLL_HOOK;
#endif
}
return true;
}
// Reads in len bytes while outputting zeroes.
bool shared_module_bitbangio_spi_read(bitbangio_spi_obj_t *self, uint8_t *data, size_t len) {
if (len > 0 && !self->has_miso) {
mp_raise_ValueError(translate("Cannot read without MISO pin."));
}
uint32_t delay_half = self->delay_half;
// only MSB transfer is implemented
// If a port defines MICROPY_PY_MACHINE_SPI_MIN_DELAY, and the configured
// delay_half is equal to this value, then the software SPI implementation
// will run as fast as possible, limited only by CPU speed and GPIO time.
#ifdef MICROPY_PY_MACHINE_SPI_MIN_DELAY
if (delay_half <= MICROPY_PY_MACHINE_SPI_MIN_DELAY) {
// Clock out zeroes while we read.
if (self->has_mosi) {
common_hal_digitalio_digitalinout_set_value(&self->mosi, false);
}
for (size_t i = 0; i < len; ++i) {
uint8_t data_in = 0;
for (int j = 0; j < 8; ++j, data_out <<= 1) {
common_hal_digitalio_digitalinout_set_value(&self->clock, 1 - self->polarity);
data_in = (data_in << 1) | common_hal_digitalio_digitalinout_get_value(&self->miso);
common_hal_digitalio_digitalinout_set_value(&self->clock, self->polarity);
}
data[i] = data_in;
}
return true;
}
#endif
if (self->has_mosi) {
common_hal_digitalio_digitalinout_set_value(&self->mosi, false);
}
for (size_t i = 0; i < len; ++i) {
uint8_t data_in = 0;
for (int j = 0; j < 8; ++j) {
if (self->phase == 0) {
common_hal_mcu_delay_us(delay_half);
common_hal_digitalio_digitalinout_set_value(&self->clock, 1 - self->polarity);
} else {
common_hal_digitalio_digitalinout_set_value(&self->clock, 1 - self->polarity);
common_hal_mcu_delay_us(delay_half);
}
data_in = (data_in << 1) | common_hal_digitalio_digitalinout_get_value(&self->miso);
if (self->phase == 0) {
common_hal_mcu_delay_us(delay_half);
common_hal_digitalio_digitalinout_set_value(&self->clock, self->polarity);
} else {
common_hal_digitalio_digitalinout_set_value(&self->clock, self->polarity);
common_hal_mcu_delay_us(delay_half);
}
}
data[i] = data_in;
// Some ports need a regular callback, but probably we don't need
// to do this every byte, or even at all.
#ifdef MICROPY_EVENT_POLL_HOOK
MICROPY_EVENT_POLL_HOOK;
#endif
}
return true;
}
// transfer
bool shared_module_bitbangio_spi_transfer(bitbangio_spi_obj_t *self, const uint8_t *dout, uint8_t *din, size_t len) {
if (len > 0 && (!self->has_mosi || !self->has_miso) ) {
mp_raise_ValueError(translate("Cannot transfer without MOSI and MISO pins."));
}
uint32_t delay_half = self->delay_half;
// only MSB transfer is implemented
// If a port defines MICROPY_PY_MACHINE_SPI_MIN_DELAY, and the configured
// delay_half is equal to this value, then the software SPI implementation
// will run as fast as possible, limited only by CPU speed and GPIO time.
#ifdef MICROPY_PY_MACHINE_SPI_MIN_DELAY
if (delay_half <= MICROPY_PY_MACHINE_SPI_MIN_DELAY) {
for (size_t i = 0; i < len; ++i) {
uint8_t data_out = dout[i];
uint8_t data_in = 0;
for (int j = 0; j < 8; ++j, data_out <<= 1) {
common_hal_digitalio_digitalinout_set_value(&self->mosi, (data_out >> 7) & 1);
common_hal_digitalio_digitalinout_set_value(&self->clock, 1 - self->polarity);
data_in = (data_in << 1) | common_hal_digitalio_digitalinout_get_value(&self->miso);
common_hal_digitalio_digitalinout_set_value(&self->clock, self->polarity);
}
din[i] = data_in;
if (dest != NULL) {
dest[i] = data_in;
}
}
return true;
}
#endif
for (size_t i = 0; i < len; ++i) {
uint8_t data_out = dout[i];
uint8_t data_in = 0;
for (int j = 0; j < 8; ++j, data_out <<= 1) {
common_hal_digitalio_digitalinout_set_value(&self->mosi, (data_out >> 7) & 1);
if (self->phase == 0) {
common_hal_mcu_delay_us(delay_half);
common_hal_digitalio_digitalinout_set_value(&self->clock, 1 - self->polarity);
} else {
common_hal_digitalio_digitalinout_set_value(&self->clock, 1 - self->polarity);
common_hal_mcu_delay_us(delay_half);
}
data_in = (data_in << 1) | common_hal_digitalio_digitalinout_get_value(&self->miso);
if (self->phase == 0) {
common_hal_mcu_delay_us(delay_half);
common_hal_digitalio_digitalinout_set_value(&self->clock, self->polarity);
} else {
common_hal_digitalio_digitalinout_set_value(&self->clock, self->polarity);
common_hal_mcu_delay_us(delay_half);
}
}
din[i] = data_in;
// Some ports need a regular callback, but probably we don't need
// to do this every byte, or even at all.
#ifdef MICROPY_EVENT_POLL_HOOK
MICROPY_EVENT_POLL_HOOK;
#endif
}
return true;
}