RX8900RTC

Arduino library that supports the SEIKO EPSON RX8900 Real-Time Clocks

citriena

I'm not good at English so correcting my English is welcome when it is wrong.

Introduction

RX8900RTC is an Arduino library that supports the SEIKO EPSON RX8900 Real-Time Clocks.

RX8900 has features of high stability (±5 seconds of month deviation with UA class) and low current consumption (typically 0.7uA when Vdd=3V, Fout=OFF).

This library is baed on the sample sketch by AKIZUKI DENSHI TSUSHO CO.,LTD. for AE-RX8900 module.

Features

Alarm

The alarm interrupt generation function generates interrupt events for alarm settings such as date, day, hour, and minute settings.

Fixed Cycle Timer

The fixed-cycle timer interrupt function generates interrupt events periodically at any fixed cycle set between 244.14us and 4095 minutes.

Time Update Interrupt

The time update interrupt function generates interrupt events at one-second or one-minute intervals.

Constructor

RX8900RTC myRTC;

Functions

Initialize

void init(void);
void begin(void);

Initialize RX8900. Eatehr of the functions above is available.

Setting the RTC time

uint8_t set(time_t t);
uint8_t write(tmElements_t tm);

Reading the RTC time

static time_t get(void);
static tmElements_t read(void);

Alarm

Setting alarm

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void setAlarm(uint8_t minute);
void setAlarm(uint8_t minute, uint8_t hour);

• minute: The minute value to set the alarm to.
• hour: The hour value to set the alarm to.

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void setDayAlarm(uint8_t minute, uint8_t hour, uint8_t daydate);

• daydate: The date of the month to set the alarm to.

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void setWeekAlarm(uint8_t minute, uint8_t hour, uint8_t daydate);

• daydate: The day(s) of the week to set the alarm to. The days are SUN, MON, TUE, WED, THU, FRI,and SAT.

Multiple days of the week can be set as SUN | SAT

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Other functions

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void alarmInterrupt(INTERRUPT_CONTROL_t interrupt);

Specifies /INT status of RX8900 when an alarm interrupt event occurs.

interrupt:

• ENABLE：/INT status changes from HIGH to LOW
• DISABLE：/INT status do not change (remains HIGH).

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bool alarm(void)

• Returns true when AF (Alarm Flag) is "1". Otherwise (AF is "0") returns false.
• When AF is "1", writes "0" to clear AF. /INT will changes to HIGH if LOW.

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void disableAlarm(void);

Stops alarm function.

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When an alarm event occurs

• AF (Alarm Flag) value changes from "0" to 1". AF value is retaind until cleared manually.

You can check the AF and clear it with "alarm(void)".

• /INT status changes to LOW if "alarmInterrupt(ENABLE)" is used. /INT status is retained until AF is cleared manually.

Fixed Cycle Timer

The fixed-cycle timer generates interrupt events periodically at a fixed cycle between 244.14us and 4095 minutes.

Functions

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void setFixedCycleTimer(uint16_t timerCounter, SOURCE_CLOCK_TYPES_t sourceClock);

Set the fixed-cycle timer interval.

• timerCounter：0~4095
• sourceClock:
  • CLOCK_4096HZ：4096Hz
  • CLOCK_64HZ：64Hz
  • SECOND_UPDATE：1Hz (Once per second)
  • MINUTE_UPDATE：1/60Hz (Once per minute)

The fixed-cycle timer interval is [sourceClock] x [timerCounter].

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void fixedCycleTimerInterrupt(INTERRUPT_CONTROL_t interrupt);

Specifies /INT status of RX8900 when a fixed-cycle timer interrupt event occurs.

interrupt:

• ENABLE：/INT status changes from HIGH to LOW
• DISABLE：/INT status do not change (remains HIGH).

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bool fixedCycleTimer(void);

• Returns true when TF(Timer Flag) is "1". Otherwise (TF is "0") returns false.
• When TF is "1" write "0" to clear TF.

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void disableFixedCycleTimer(void);

Stops fixed-cycle timer function.

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When a fixed-cycle timer interrupt event occurs

• TF(Timer Flag) value changes from "0" to 1". TF value is retaind until cleared manually.

You can check the TF and clear it with "fixedCycleTimer(void)".

• /INT status changes LOW if "fixedCycleTimerInterrupt(ENABLE)" is used. /INT status is automatically cleared 7.813ms or 722us (sourceClock is CLOCK_4096HZ) after the event occured.

Timing of counting down and interrupts of the fixed-cycle timer

• When the source clock has been set to "SECOND_UPDATE" or "MINUTE_UPDATE", the timing of both countdown and interrupts is coordinated with the internal clock update timing.
• The first countdown timing is therefore not exact one sourceClock cycle from the start. The first fixedCycleTimer interrupt event will occure ealier than fixed-cycle.

Time Update Interrupt

The time update interrupt function generates interrupt events at one-second or one-minute intervals.

The events will occure according to the timing of the internal clock update.

The time update interrupt function can not be fully stopped.

Functions

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void setTimeUpdateTimer(USEL_t usel);

Set time update timer interval.

usel:

• UPDATE_SECOND_INT: interrupt event will occure once per second.
• UPDATE_MINUTE_INT: interrupt event will occure once per minute.

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void timeUpdateTimerInterrupt(INTERRUPT_CONTROL_t interrupt);

Specifies /INT status of RX8900 when a time update interrupt event occurs.

interrupt:

• ENABLE：/INT status changes from HIGH to LOW
• DISABLE：/INT status do not change (remains HIGH).

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bool timeUpdateTimer(void);

• Returns true when UF (Update Flag) is "1". Otherwise (UF is "0") returns false.
• When UF is "1" write "0" to cleart UF.

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When a time update timer interrupt event occurs

• UF(Updater Flag) value changes from "0" to 1". UF value is retaind until cleared manually.

You can check the UF and clear it with "timeUpdateTimer(void)".

• /INT status changes LOW if "timeUpdateTimerInterrupt(ENABLE)" is used. /INT status is automatically cleared 15.63ms (usel is UPDATE_MINUTE_INT) or 500ms (usel is UPDATE_SECOND_INT) after the event occured.

Other functions

float temperature(void);

Returns internal temperature sensor value in Celcius.

Usage

See sample skeches for basic usage.

See Application Manual for details of each function. https://www5.epsondevice.com/en/products/rtc/rx8900ce.html

Releases

1.0.0 - Mar 4, 2019

1.0.1 - May 23, 2020

• rename some functions constants and variables

1.0.2 - Mov 05, 2023

• bug fix: modify WEEK_TYPES_t definition