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Use the builtin RTC and display it

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Its roughly %15 fast, and initializes to zero, but the display
currently shows HH:MM:SS AM/PM.
This commit is contained in:
Max Regan
2019-03-11 22:56:08 -07:00
parent dedcb5af71
commit d5bfecedb2
10 changed files with 285 additions and 8 deletions
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rtc.c Normal file
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/*
* Copyright (C) 2019 Max Regan
*
* 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 "rtc.h"
#include "stm32l0xx.h"
#include "macros.h"
static void enable_rtc_write()
{
/*<! Disable write protection */
RTC->WPR = 0xCA;
RTC->WPR = 0x53;
}
static void disable_rtc_write()
{
/*<! Disable write protection */
RTC->WPR = 0x00;
}
void rtc_init()
{
uint32_t temp = RCC->CSR;
SET(RCC->CSR, RCC_CSR_RTCRST);
SET(RCC->APB1ENR, RCC_APB1ENR_PWREN);
SET(PWR->CR, PWR_CR_DBP);
/*<! Set RTC input clock to the LSI (low-speed internal 32.768kHz) clock */
SET_TO(temp, RCC_CSR_RTCSEL, RCC_CSR_RTCSEL_1);
SET(temp, RCC_CSR_RTCEN);
RCC->CSR = temp;
enable_rtc_write();
RTC->ISR = RTC_ISR_INIT;
while (!(RTC->ISR & RTC_ISR_INITF)) {}
/*<! Set the Clock Prescalers (32.768kHz / 128 / 256 = 1Hz */
/*<! Set the Async prescaler to the Maximum (divide the clock by 128) */
SET_TO(RTC->PRER, RTC_PRER_PREDIV_A, RTC_PRER_PREDIV_A);
/*<! Set the Syncronous scaler (divide the clock by 255 + 1) */
SET_TO(RTC->PRER, RTC_PRER_PREDIV_S, 255);
/*<! Load initial date and time */
// TODO
/* uint32_t time = 0; */
/* uint32_t date = 0; */
/*<! Set the date and time format */
// TODO: currently defaults to 24hr
CLR(RTC->ISR, RTC_ISR_INIT);
disable_rtc_write();
}
void rtc_get_time_bcd(struct time_bcd *tm_bcd)
{
uint32_t time = RTC->TR;
tm_bcd->hour_tens = STM32_FIELD(time, RTC_TR_HT);
tm_bcd->hour_ones = STM32_FIELD(time, RTC_TR_HU);
tm_bcd->minute_tens = STM32_FIELD(time, RTC_TR_MNT);
tm_bcd->minute_ones = STM32_FIELD(time, RTC_TR_MNU);
tm_bcd->second_tens = STM32_FIELD(time, RTC_TR_ST);
tm_bcd->second_ones = STM32_FIELD(time, RTC_TR_SU);
tm_bcd->pm = STM32_FIELD(time, RTC_TR_PM);
}