stm32_manageable_psu.c

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/**
 * \file heivs/stm32_manageable_psu.c
 *
 * \author marc dot pignat at hevs dot ch
 */

#include "heivs/stm32_manageable_psu.h"
#include "heivs/stm32_mcp4552.h"
#include "heivs/bsp.h"

static const struct mcp4552_t mcp4552[] =
{
        {
            .bus            = &bus_i2c[0],
            .i2c_address    = 0x2c
        },
        {
            .bus            = &bus_i2c[0],
            .i2c_address    = 0x2d
        },
};

static const struct gpio_t gpio_enable_not0 = DEF_GPIOG(14, GPIO_OUTPUT_1);
static const struct gpio_t gpio_enable_not1 = DEF_GPIOG(13, GPIO_OUTPUT_1);

struct manageable_psu_t
{
    const struct mcp4552_t  *potentiometer;
    const struct gpio_t     *enable_not;
};

static const struct manageable_psu_t psu[] =
{
    {
        .potentiometer  = &mcp4552[0],
        .enable_not     = &gpio_enable_not0,
    },
    {
        .potentiometer  = &mcp4552[1],
        .enable_not     = &gpio_enable_not1,
    },
};

static status_e psu_set(const struct manageable_psu_t *psu, uint32_t mv)
{
    /**
     * Output formula
     * Ra = ((Vout / 0.6663) - 1) * Rb
     * Vout should be < Vin
     *
     * Rb is 13k
     * Vin = 3.3V
     *
     * Ra = 50k*value/256
     * -> value = 256 * Ra / 50k
     * -> value = 256 * ((mv/1000 / 0.6663)- 1) * 13k / 50k
     * -> value = 256 * ((mv / 666.3) - 1) * 13 / 50
     */
    uint64_t value = mv;
    uint32_t f = 1000;

    gpio_setup(psu->enable_not);
    gpio_set(psu->enable_not, 1);

    if (mv > 3300)
    {
        return ERROR_BAD_PARAM;
    }

    if (mv < 666)
    {
        return ERROR_BAD_PARAM;
    }

    value *= 10 * f;
    value /= 6663;
    value -= f;

    value *= 13 * 256;
    value /= 50;
    value /= f;

    value = min(value, (uint32_t)256);

    gpio_set(psu->enable_not, 0);

    mcp4552_set(psu->potentiometer, value);

    return NO_ERROR;
}

status_e psu_aux0_set(uint32_t mv)
{
    return psu_set(&psu[0], mv);
}

status_e psu_aux1_set(uint32_t mv)
{
    return psu_set(&psu[1], mv);
}