circuitpython/stmhal/rtc.c

#include <stdio.h>

#include "stm32f4xx_hal.h"

#include "misc.h"
#include "mpconfig.h"
#include "qstr.h"
#include "obj.h"
#include "runtime.h"
#include "rtc.h"

RTC_HandleTypeDef RTCHandle;

// rtc_info indicates various things about RTC startup
// it's a bit of a hack at the moment
static machine_uint_t rtc_info;

// Note: LSI is around (32KHz), these dividers should work either way
// ck_spre(1Hz) = RTCCLK(LSE) /(uwAsynchPrediv + 1)*(uwSynchPrediv + 1)
#define RTC_ASYNCH_PREDIV (0x7f)
#define RTC_SYNCH_PREDIV  (0x00ff)

#if 0
#define RTC_INFO_USE_EXISTING (0)
#define RTC_INFO_USE_LSE (1)
#define RTC_INFO_USE_LSI (3)

void rtc_init(void) {
    // Enable the PWR clock
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);

    // Allow access to RTC
    PWR_BackupAccessCmd(ENABLE);

    if (RTC_ReadBackupRegister(RTC_BKP_DR0) == 0x32F2) {
        // RTC still alive, so don't re-init it
        // wait for RTC APB register synchronisation
        RTC_WaitForSynchro();
        rtc_info = RTC_INFO_USE_EXISTING;
        return;
    }

    uint32_t timeout = 10000000;

    // Enable the PWR clock
    RCC_APB1PeriphClockCmd(RCC_APB1Periph_PWR, ENABLE);

    // Allow access to RTC
    PWR_BackupAccessCmd(ENABLE);

    // Enable the LSE OSC
    RCC_LSEConfig(RCC_LSE_ON);

    // Wait till LSE is ready
    machine_uint_t sys_tick = sys_tick_counter;
    while((RCC_GetFlagStatus(RCC_FLAG_LSERDY) == RESET) && (--timeout > 0)) {
    }

    // record how long it took for the RTC to start up
    rtc_info = (sys_tick_counter - sys_tick) << 2;

    // If LSE timed out, use LSI instead
    if (timeout == 0) {
        // Disable the LSE OSC
        RCC_LSEConfig(RCC_LSE_OFF);

        // Enable the LSI OSC
        RCC_LSICmd(ENABLE);

        // Wait till LSI is ready
        while(RCC_GetFlagStatus(RCC_FLAG_LSIRDY) == RESET) {
        }

        // Use LSI as the RTC Clock Source
        RCC_RTCCLKConfig(RCC_RTCCLKSource_LSI);

        // record that we are using the LSI
        rtc_info |= RTC_INFO_USE_LSI;
    } else {
        // Use LSE as the RTC Clock Source
        RCC_RTCCLKConfig(RCC_RTCCLKSource_LSE);

        // record that we are using the LSE
        rtc_info |= RTC_INFO_USE_LSE;
    }

    // Note: LSI is around (32KHz), these dividers should work either way
    // ck_spre(1Hz) = RTCCLK(LSE) /(uwAsynchPrediv + 1)*(uwSynchPrediv + 1)
    uint32_t uwSynchPrediv = 0xFF;
    uint32_t uwAsynchPrediv = 0x7F;

    // Enable the RTC Clock
    RCC_RTCCLKCmd(ENABLE);

    // Wait for RTC APB registers synchronisation
    RTC_WaitForSynchro();

    // Configure the RTC data register and RTC prescaler
    RTC_InitTypeDef RTC_InitStructure;
    RTC_InitStructure.RTC_AsynchPrediv = uwAsynchPrediv;
    RTC_InitStructure.RTC_SynchPrediv = uwSynchPrediv;
    RTC_InitStructure.RTC_HourFormat = RTC_HourFormat_24;
    RTC_Init(&RTC_InitStructure);

    // Set the date (BCD)
    RTC_DateTypeDef RTC_DateStructure;
    RTC_DateStructure.RTC_Year = 0x13;
    RTC_DateStructure.RTC_Month = RTC_Month_October;
    RTC_DateStructure.RTC_Date = 0x26;
    RTC_DateStructure.RTC_WeekDay = RTC_Weekday_Saturday;
    RTC_SetDate(RTC_Format_BCD, &RTC_DateStructure);

    // Set the time (BCD)
    RTC_TimeTypeDef RTC_TimeStructure;
    RTC_TimeStructure.RTC_H12     = RTC_H12_AM;
    RTC_TimeStructure.RTC_Hours   = 0x01;
    RTC_TimeStructure.RTC_Minutes = 0x53;
    RTC_TimeStructure.RTC_Seconds = 0x00;
    RTC_SetTime(RTC_Format_BCD, &RTC_TimeStructure);

    // Indicator for the RTC configuration
    RTC_WriteBackupRegister(RTC_BKP_DR0, 0x32F2);
}
#endif

static void RTC_CalendarConfig(void);

void rtc_init(void) {
    RTCHandle.Instance = RTC;

    /* Configure RTC prescaler and RTC data registers */
    /* RTC configured as follow:
      - Hour Format    = Format 24
      - Asynch Prediv  = Value according to source clock
      - Synch Prediv   = Value according to source clock
      - OutPut         = Output Disable
      - OutPutPolarity = High Polarity
      - OutPutType     = Open Drain */
    RTCHandle.Init.HourFormat = RTC_HOURFORMAT_24;
    RTCHandle.Init.AsynchPrediv = RTC_ASYNCH_PREDIV;
    RTCHandle.Init.SynchPrediv = RTC_SYNCH_PREDIV;
    RTCHandle.Init.OutPut = RTC_OUTPUT_DISABLE;
    RTCHandle.Init.OutPutPolarity = RTC_OUTPUT_POLARITY_HIGH;
    RTCHandle.Init.OutPutType = RTC_OUTPUT_TYPE_OPENDRAIN;

    machine_uint_t tick = HAL_GetTick();

    if (HAL_RTC_Init(&RTCHandle) != HAL_OK) {
        // init error
        rtc_info = 0xffff; // indicate error
        return;
    }

    // record how long it took for the RTC to start up
    rtc_info = HAL_GetTick() - tick;

    // check data stored in BackUp register0
    if (HAL_RTCEx_BKUPRead(&RTCHandle, RTC_BKP_DR0) != 0x32f2) {
        // fresh reset; configure RTC Calendar
        RTC_CalendarConfig();
    } else {
        // RTC was previously set, so leave it alon
        if(__HAL_RCC_GET_FLAG(RCC_FLAG_PORRST) != RESET) {
            // power on reset occured
            rtc_info |= 0x10000;
        }
        if(__HAL_RCC_GET_FLAG(RCC_FLAG_PINRST) != RESET) {
            // external reset occured
            rtc_info |= 0x20000;
        }
        // Clear source Reset Flag
        __HAL_RCC_CLEAR_RESET_FLAGS();
    }
}

static void RTC_CalendarConfig(void) {
    // set the date to 1st Jan 2014
    RTC_DateTypeDef date;
    date.Year = 0x14;
    date.Month = RTC_MONTH_JANUARY;
    date.Date = 0x01;
    date.WeekDay = RTC_WEEKDAY_WEDNESDAY;

    if(HAL_RTC_SetDate(&RTCHandle, &date, FORMAT_BCD) != HAL_OK) {
        // init error
        return;
    }

    // set the time to 00:00:00
    RTC_TimeTypeDef time;
    time.Hours = 0x00;
    time.Minutes = 0x00;
    time.Seconds = 0x00;
    time.TimeFormat = RTC_HOURFORMAT12_AM;
    time.DayLightSaving = RTC_DAYLIGHTSAVING_NONE;
    time.StoreOperation = RTC_STOREOPERATION_RESET;

    if (HAL_RTC_SetTime(&RTCHandle, &time, FORMAT_BCD) != HAL_OK) {
        // init error
        return;
    }

    // write data to indicate the RTC has been set
    HAL_RTCEx_BKUPWrite(&RTCHandle, RTC_BKP_DR0, 0x32f2);
}

/******************************************************************************/
// Micro Python bindings

typedef struct _pyb_rtc_obj_t {
    mp_obj_base_t base;
} pyb_rtc_obj_t;

STATIC const pyb_rtc_obj_t pyb_rtc_obj = {{&pyb_rtc_type}};

STATIC mp_obj_t pyb_rtc_make_new(mp_obj_t type_in, uint n_args, uint n_kw, const mp_obj_t *args) {
    // check arguments
    mp_arg_check_num(n_args, n_kw, 0, 0, false);

    // return constant object
    return (mp_obj_t)&pyb_rtc_obj;
}

mp_obj_t pyb_rtc_info(mp_obj_t self_in) {
    return mp_obj_new_int(rtc_info);
}
MP_DEFINE_CONST_FUN_OBJ_1(pyb_rtc_info_obj, pyb_rtc_info);

mp_obj_t pyb_rtc_datetime(uint n_args, const mp_obj_t *args) {
    if (n_args == 1) {
        // get date and time
        // note: need to call get time then get date to correctly access the registers
        RTC_DateTypeDef date;
        RTC_TimeTypeDef time;
        HAL_RTC_GetTime(&RTCHandle, &time, FORMAT_BIN);
        HAL_RTC_GetDate(&RTCHandle, &date, FORMAT_BIN);
        mp_obj_t tuple[8] = {
            mp_obj_new_int(2000 + date.Year),
            mp_obj_new_int(date.Month),
            mp_obj_new_int(date.Date),
            mp_obj_new_int(date.WeekDay),
            mp_obj_new_int(time.Hours),
            mp_obj_new_int(time.Minutes),
            mp_obj_new_int(time.Seconds),
            mp_obj_new_int(time.SubSeconds),
        };
        return mp_obj_new_tuple(8, tuple);
    } else {
        // set date and time
        mp_obj_t *items;
        mp_obj_get_array_fixed_n(args[1], 8, &items);

        RTC_DateTypeDef date;
        date.Year = mp_obj_get_int(items[0]) - 2000;
        date.Month = mp_obj_get_int(items[1]);
        date.Date = mp_obj_get_int(items[2]);
        date.WeekDay = mp_obj_get_int(items[3]);
        HAL_RTC_SetDate(&RTCHandle, &date, FORMAT_BCD);

        RTC_TimeTypeDef time;
        time.Hours = mp_obj_get_int(items[4]);
        time.Minutes = mp_obj_get_int(items[5]);
        time.Seconds = mp_obj_get_int(items[6]);
        time.SubSeconds = mp_obj_get_int(items[7]);
        time.TimeFormat = RTC_HOURFORMAT12_AM;
        time.DayLightSaving = RTC_DAYLIGHTSAVING_NONE;
        time.StoreOperation = RTC_STOREOPERATION_SET;
        HAL_RTC_SetTime(&RTCHandle, &time, FORMAT_BCD);

        return mp_const_none;
    }
}
MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_rtc_datetime_obj, 1, 2, pyb_rtc_datetime);

STATIC const mp_map_elem_t pyb_rtc_locals_dict_table[] = {
    { MP_OBJ_NEW_QSTR(MP_QSTR_info), (mp_obj_t)&pyb_rtc_info_obj },
    { MP_OBJ_NEW_QSTR(MP_QSTR_datetime), (mp_obj_t)&pyb_rtc_datetime_obj },
};
STATIC MP_DEFINE_CONST_DICT(pyb_rtc_locals_dict, pyb_rtc_locals_dict_table);

const mp_obj_type_t pyb_rtc_type = {
    { &mp_type_type },
    .name = MP_QSTR_RTC,
    .make_new = pyb_rtc_make_new,
    .locals_dict = (mp_obj_t)&pyb_rtc_locals_dict,
};