openmv/ports/stm32/soft_i2c.c
iabdalkader daf2bb30da misc: Restructure repo.
Signed-off-by: iabdalkader <i.abdalkader@gmail.com>
2025-04-13 08:28:34 +02:00

188 lines
5.2 KiB
C

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