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https://github.com/openmv/openmv.git
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188 lines
5.2 KiB
C
188 lines
5.2 KiB
C
/*
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* SPDX-License-Identifier: MIT
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*
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* Copyright (C) 2013-2024 OpenMV, LLC.
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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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* Software I2C implementation.
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*/
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#include <string.h>
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#include <stdint.h>
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#include <stdbool.h>
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#include "py/mphal.h"
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#include "soft_i2c.h"
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#include "omv_boardconfig.h"
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#include "omv_gpio.h"
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#if defined(OMV_SOFT_I2C_SIOC_PIN)
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#define ACK 0
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#define NACK 1
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static void delay(void) {
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for (volatile int i = 0; i < OMV_SOFT_I2C_SPIN_DELAY; i++) {
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;
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}
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}
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static void i2c_start(void) {
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/* The start of data transmission occurs when
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SIO_D is driven low while SIO_C is high */
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omv_gpio_write(OMV_SOFT_I2C_SIOD_PIN, 0);
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delay();
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omv_gpio_write(OMV_SOFT_I2C_SIOC_PIN, 0);
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delay();
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}
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static void i2c_stop(void) {
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/* The stop of data transmission occurs when
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SIO_D is driven high while SIO_C is high */
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omv_gpio_write(OMV_SOFT_I2C_SIOC_PIN, 1);
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delay();
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omv_gpio_write(OMV_SOFT_I2C_SIOD_PIN, 1);
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delay();
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}
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static uint8_t i2c_read_byte(char ack) {
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uint8_t data = 0;
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omv_gpio_write(OMV_SOFT_I2C_SIOD_PIN, 1);
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delay();
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for (char i = 0; i < 8; i++) {
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omv_gpio_write(OMV_SOFT_I2C_SIOC_PIN, 1);
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delay();
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data += data + omv_gpio_read(OMV_SOFT_I2C_SIOD_PIN);
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delay();
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omv_gpio_write(OMV_SOFT_I2C_SIOC_PIN, 0);
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delay();
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}
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/* Write ACK */
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omv_gpio_write(OMV_SOFT_I2C_SIOD_PIN, ack);
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delay();
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omv_gpio_write(OMV_SOFT_I2C_SIOC_PIN, 1);
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delay();
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omv_gpio_write(OMV_SOFT_I2C_SIOC_PIN, 0);
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delay();
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omv_gpio_write(OMV_SOFT_I2C_SIOD_PIN, 0);
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delay();
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return data;
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}
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static char i2c_write_byte(uint8_t data) {
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char i;
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for (i = 0; i < 8; i++) {
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omv_gpio_write(OMV_SOFT_I2C_SIOD_PIN, (data >> (7 - i)) & 1);
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delay();
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omv_gpio_write(OMV_SOFT_I2C_SIOC_PIN, 1);
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delay();
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omv_gpio_write(OMV_SOFT_I2C_SIOC_PIN, 0);
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delay();
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}
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omv_gpio_write(OMV_SOFT_I2C_SIOD_PIN, 1);
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delay();
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omv_gpio_write(OMV_SOFT_I2C_SIOC_PIN, 1);
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delay();
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/* Read ACK */
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i = omv_gpio_read(OMV_SOFT_I2C_SIOD_PIN);
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delay();
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omv_gpio_write(OMV_SOFT_I2C_SIOC_PIN, 0);
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delay();
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omv_gpio_write(OMV_SOFT_I2C_SIOD_PIN, 0);
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delay();
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return i;
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}
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int soft_i2c_read_bytes(uint8_t slv_addr, uint8_t *buf, int len, bool stop) {
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int ret = 0;
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mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
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i2c_start();
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ret |= i2c_write_byte(slv_addr | 1);
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for (int i = 0; i < len; i++) {
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buf[i] = i2c_read_byte((i != (len - 1)) ? ACK : NACK);
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}
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if (stop) {
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i2c_stop();
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} else {
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omv_gpio_write(OMV_SOFT_I2C_SIOD_PIN, 1);
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delay();
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omv_gpio_write(OMV_SOFT_I2C_SIOC_PIN, 1);
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delay();
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}
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MICROPY_END_ATOMIC_SECTION(atomic_state);
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return ret;
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}
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int soft_i2c_write_bytes(uint8_t slv_addr, uint8_t *buf, int len, bool stop) {
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int ret = 0;
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mp_uint_t atomic_state = MICROPY_BEGIN_ATOMIC_SECTION();
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i2c_start();
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ret |= i2c_write_byte(slv_addr);
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for (int i = 0; i < len; i++) {
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ret |= i2c_write_byte(buf[i]);
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}
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if (stop) {
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i2c_stop();
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} else {
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omv_gpio_write(OMV_SOFT_I2C_SIOD_PIN, 1);
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delay();
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omv_gpio_write(OMV_SOFT_I2C_SIOC_PIN, 1);
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delay();
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}
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MICROPY_END_ATOMIC_SECTION(atomic_state);
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return ret;
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}
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void soft_i2c_init() {
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omv_gpio_write(OMV_SOFT_I2C_SIOC_PIN, 1); // Set first to prevent glitches.
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omv_gpio_config(OMV_SOFT_I2C_SIOC_PIN, OMV_GPIO_MODE_OUTPUT_OD, OMV_GPIO_PULL_NONE, OMV_GPIO_SPEED_LOW, -1);
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omv_gpio_write(OMV_SOFT_I2C_SIOD_PIN, 1); // Set first to prevent glitches.
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omv_gpio_config(OMV_SOFT_I2C_SIOD_PIN, OMV_GPIO_MODE_OUTPUT_OD, OMV_GPIO_PULL_NONE, OMV_GPIO_SPEED_LOW, -1);
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for (volatile int i = 0; i < 1000; i++) {
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;
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}
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for (int j = 0; j < 127; j++) {
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// initialize bus
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soft_i2c_write_bytes(j << 1, NULL, 0, true);
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}
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}
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void soft_i2c_deinit() {
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for (volatile int i = 0; i < 1000; i++) {
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;
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}
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omv_gpio_deinit(OMV_SOFT_I2C_SIOC_PIN);
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omv_gpio_deinit(OMV_SOFT_I2C_SIOD_PIN);
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}
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#endif // defined(OMV_SOFT_I2C_SIOC_PIN)
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