epd42/components/drivers_nrf/sdio/sdio.c

/* Copyright (c) 2009 Nordic Semiconductor. All Rights Reserved.
 *
 * The information contained herein is property of Nordic Semiconductor ASA.
 * Terms and conditions of usage are described in detail in NORDIC
 * SEMICONDUCTOR STANDARD SOFTWARE LICENSE AGREEMENT.
 *
 * Licensees are granted free, non-transferable use of the information. NO
 * WARRANTY of ANY KIND is provided. This heading must NOT be removed from
 * the file.
 *
 */

#include <stdint.h>

#include "nrf.h"
#include "nrf_delay.h"
#include "sdio.h"
#include "nrf_gpio.h"

#include "sdio_config.h"

/*lint ++flb "Enter library region" */

/*lint -e717 -save "Suppress do {} while (0) for these macros" */
#define SDIO_CLOCK_HIGH()   do { NRF_GPIO->OUTSET = (1UL << SDIO_CONFIG_CLOCK_PIN_NUMBER); } while (0) /*!< Pulls SCL line high */
#define SDIO_CLOCK_LOW()    do { NRF_GPIO->OUTCLR = (1UL << SDIO_CONFIG_CLOCK_PIN_NUMBER); } while (0) /*!< Pulls SCL line low */
#define SDIO_DATA_HIGH()    do { NRF_GPIO->OUTSET = (1UL << SDIO_CONFIG_DATA_PIN_NUMBER); } while (0)  /*!< Pulls SDA line high */
#define SDIO_DATA_LOW()     do { NRF_GPIO->OUTCLR = (1UL << SDIO_CONFIG_DATA_PIN_NUMBER); } while (0)  /*!< Pulls SDA line low */
#define SDIO_DATA_OUTPUT()  do { NRF_GPIO->DIRSET = (1UL << SDIO_CONFIG_DATA_PIN_NUMBER); } while (0)  /*!< Configures SDA pin as output */
#define SDIO_CLOCK_OUTPUT() do { NRF_GPIO->DIRSET = (1UL << SDIO_CONFIG_CLOCK_PIN_NUMBER); } while (0) /*!< Configures SCL pin as output */
/*lint -restore */

/*lint -emacro(845,SDIO_DATA_INPUT) // A zero has been given as right argument to operator '|'" */

#define SDIO_DATA_INPUT() do {                       \
        nrf_gpio_cfg_input(25, NRF_GPIO_PIN_NOPULL); \
} while (0)

#define SDIO_DATA_READ()  ((NRF_GPIO->IN >> SDIO_CONFIG_DATA_PIN_NUMBER) & 0x1UL)  /*!< Reads current state of SDA */
#define SDIO_CLOCK_READ() ((NRF_GPIO->IN >> SDIO_CONFIG_CLOCK_PIN_NUMBER) & 0x1UL) /*!< Reads current state of SCL */
#define SDIO_DELAY()      nrf_delay_us(10)                                         /*!< Time to wait when pin states are changed. For fast-mode the delay can be zero and for standard-mode 4 us delay is sufficient. */

void sdio_init(void)
{
    SDIO_CLOCK_HIGH();
    SDIO_DATA_HIGH();
    SDIO_CLOCK_OUTPUT();
    SDIO_DATA_INPUT();

    // If slave is stuck in the middle of transfer, clock out bits until the slave ACKs the transfer
    for (uint_fast8_t i = 16; i--;)
    {
        SDIO_DELAY();
        SDIO_CLOCK_LOW();
        SDIO_DELAY();
        SDIO_CLOCK_HIGH();
        SDIO_DELAY();

        if (SDIO_DATA_READ())
        {
            break;
        }
    }

    for (uint_fast8_t i = 5; i--;)
    {
        SDIO_DELAY();
        SDIO_CLOCK_LOW();
        SDIO_DELAY();
        SDIO_CLOCK_HIGH();
    }

    SDIO_DATA_OUTPUT();
    SDIO_DATA_HIGH();

    SDIO_DELAY();
}

uint8_t sdio_read_byte(uint8_t address)
{
    uint8_t data_byte = 0;

    SDIO_DATA_OUTPUT();

    for (uint_fast8_t i = 8; i--;)
    {
        SDIO_DELAY();

        SDIO_CLOCK_LOW();

        if (address & (1U << i))
        {
            SDIO_DATA_HIGH();
        }
        else
        {
            SDIO_DATA_LOW();
        }

        SDIO_DELAY();

        SDIO_CLOCK_HIGH();
    }

    nrf_delay_us(20);

    SDIO_DATA_INPUT();

    for (uint_fast8_t i = 8; i--;)
    {
        SDIO_CLOCK_LOW();
        SDIO_DELAY();
        SDIO_CLOCK_HIGH();
        SDIO_DELAY();
        data_byte |= (uint8_t)(SDIO_DATA_READ() << i);
    }

    SDIO_DATA_HIGH();
    SDIO_DATA_OUTPUT();

    SDIO_DELAY();

    return data_byte;
}

void sdio_read_burst(uint8_t * target_buffer, uint8_t target_buffer_size)
{
    uint_fast8_t address = 0x63;

    SDIO_DATA_OUTPUT();

    for (uint_fast8_t bit_index=8; bit_index--;)
    {
        SDIO_CLOCK_LOW();

        if (address & (1U << bit_index))
        {
            SDIO_DATA_HIGH();
        }
        else
        {
            SDIO_DATA_LOW();
        }

        SDIO_CLOCK_HIGH();
    }

    SDIO_DATA_INPUT();

    for (uint_fast8_t target_buffer_index = 0; target_buffer_index < target_buffer_size; target_buffer_index++)
    {
        target_buffer[target_buffer_index] = 0;

        for (uint_fast8_t bit_index = 8; bit_index--;)
        {
            SDIO_CLOCK_LOW();
            SDIO_CLOCK_HIGH();
            target_buffer[target_buffer_index] |= (uint8_t)(SDIO_DATA_READ() << bit_index);
        }
    }
}

void sdio_write_byte(uint8_t address, uint8_t data_byte)
{
    // Add write indication bit
    address |= 0x80;

    SDIO_DATA_OUTPUT();

    for (uint_fast8_t i = 8; i--;)
    {
        SDIO_DELAY();

        SDIO_CLOCK_LOW();

        if (address & (1U << i))
        {
            SDIO_DATA_HIGH();
        }
        else
        {
            SDIO_DATA_LOW();
        }

        SDIO_DELAY();

        SDIO_CLOCK_HIGH();
    }

    SDIO_DELAY();

    for (uint_fast8_t i = 8; i--;)
    {
        SDIO_CLOCK_LOW();

        if (data_byte & (1U << i))
        {
            SDIO_DATA_HIGH();
        }
        else
        {
            SDIO_DATA_LOW();
        }

        SDIO_DELAY();

        SDIO_CLOCK_HIGH();

        SDIO_DELAY();
    }

    SDIO_DATA_HIGH();

    SDIO_DELAY();
}

/*lint --flb "Leave library region" */