modpybi2c.c

/*
 * 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 "osapi.h"
#include "gpio.h"

#include "py/runtime.h"
#include "modpyb.h"

typedef struct _pyb_i2c_obj_t {
    mp_obj_base_t base;
    pyb_pin_obj_t *scl;
    pyb_pin_obj_t *sda;
} pyb_i2c_obj_t;

// these set the frequency of SCL
#define mphal_i2c_wait_a() os_delay_us(2)
#define mphal_i2c_wait_b() os_delay_us(1)

STATIC void mphal_i2c_set_sda(pyb_i2c_obj_t *self, uint8_t sda) {
    uint32_t port = self->sda->phys_port;
    sda &= 0x01;
    gpio_output_set(sda << port, (1 - sda) << port, 1 << port, 0);
}

STATIC void mphal_i2c_set_scl(pyb_i2c_obj_t *self, uint8_t scl) {
    uint32_t port = self->scl->phys_port;
    scl &= 0x01;
    gpio_output_set(scl << port, (1 - scl) << port, 1 << port, 0);
}

STATIC int mphal_i2c_get_sda(pyb_i2c_obj_t *self) {
    return GPIO_INPUT_GET(GPIO_ID_PIN(self->sda->phys_port));
}

STATIC void mphal_i2c_start(pyb_i2c_obj_t *self) {
    mphal_i2c_set_sda(self, 1);
    mphal_i2c_wait_a();
    mphal_i2c_set_scl(self, 1);
    mphal_i2c_wait_a();
    mphal_i2c_set_sda(self, 0);