Questions tagged [rtc]
Questions regarding Real Time Clocks (RTCs) which can be a timekeeper IC used by microcontrollers, or using a microcontroller as an accurate timekeeper. Some have calendar, alarm, interrupt or heartbeat features, while some simply keep track of time since last programmed (Epoch timers are similar).
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DS3231 ESP32 I2C problem?
I've got a new board prototype with an ESP32-S3 and a BME688 and and DS3231 on the same I2C bus (using pins 48=SDA and 47=SCL). I run the Examples => Wire => WireScan example making the ...
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STM32F103C8T6 BluePill - HAL_RTC_AlarmAEventCallback - Not call
I have a problem: I can’t get the alarm clock to work on the BluePill board. I need to get an interrupt to wake up the chip from Stop mode. It seems to me that the problem is in my BluePill board, ...
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Does the ESP32 WROOM-32 have an internal RTC?
I am working on an ESP32 WROOM-32 now. My purpose is to have it read some data every 15 minutes, in between the ESP32 goes to sleep mode.
Does the ESP32 have an internal RTC or timer? I searched on ...
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Is my circuit correct (Nixie Tube Clock)?
I am making a clock with Nixie tubes IN-12 A and made a circuit. I would like to know if it is correct before making the PCB and 3D case.
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Powering RTC DS3231 through BAT pin while keeping the coin cell battery in place
I'm working on a battery-powered DSLR camera controller with a MCU (ATMEGA328P) that spends most of the time in deep sleep and a RTC (DS3231) that wakes up the MCU a few times a day to take a picture. ...
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Can I read time data from an RTC (Real-Time Clock) chip without a microprocessor?
I have an HD146818 (Motorola MC146818) integrated circuit, which is a real-time clock. I would like to build a simple clock on it, which will control an 8-segment display. I read the datasheet for ...
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Real Time Clock PCF8523 & ESP32-C6: Registers don’t match data sheet?
I'm trying to use a PCF8523 RTC (via adafruit's assembled breakout board) with an ESP32-C6 (via ESP32-C6-DevKitC-1) over I2C.
It appears the bits inside each register shift around unexpectedly? ...
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STM32F746 Disco: Why doesn't the RTC generate an alarm A interrupt?
I'm trying to generate an interrupt every 60 seconds using alarm A. I put a HAL_GPIO_Toggle instruction inside the interrupt HAL_RTC_AlarmAEventCallback to turn an LED on to see if it triggers but I ...
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Seeking a equivlanet RTC for replacing a BQ4285S RTC
I'm going to start a project that requires a BQ4285S RTC. The problem is finding a BQ4285S (other than from questionable sources in China directly) or equivalent replacement since I don't know if any ...
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Read battery voltage for external RTC on STM32
I am using STM32F446RE for my application to just log the time accurately. I have an RTC module DS3231SN connected to the STM32 on the I2C. The RTC is connected to a coin cell battery CR2032 for a ...
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Building an PTP TSU + RTC module
I want to build a simple Precision Time Protocol Timestamp Unit and Real-Time clock (PTP TSU + RTC module). My accuracy requirement is +-50ns.
I found a good opencore ha1588 which fits for RTL part.
...
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How can I perform a slow shutdown on the power supply of an RTC after turning off the circuit?
I have designed a circuit that includes an RTC, the model is RV-3032-C7. We were able to configure it and the device performs its function, but I have a big problem. Occasionally, when I turn off and ...
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Newly purchased DS1302 IC not working
I want to add a RTC in my own custom PCB using a DS1302 IC. I am using the Arduino IDE and an ESP32 controller.
I made a PCB and tried to run it but it failed to read data from the RTC. Just to make ...
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MSP430 RTC_B Back up Battery Supply
I plan on using MSP430F5636IPZ from Texas Instruments as my microcontroller in a project which I am currently working on. The MCU comes with a RTC_B (Real Time Clock) with Battery Backup capability.
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Is it a good idea to use the internal RTC of a microcontroller or is it better to use an external one?
Well, I am designing a datalogger and I want to use an STM32L4R5VGT6 mcu and I know that this microcontroller has an internal RTC, so to avoid buying an external RTC I want to use the one that comes ...
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DS3231 RTC interfacing with Raspberry Pi 3B
I want to interface a DS3231 RTC module with my Raspberry Pi 3b model in a project. As we all know this RTC module supports only I2C communication, where pin no. 3 and 5 of the Raspberry Pi are used ...
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I'd like to request a review/bashing of this circuit for a high precision soil moisture sensing and analysis device. Where did I go wrong?
Below you will find a buffet of questions and the schematic for my device. (Click on it and you will get the full-size image.) Please tear this up. I'm a self-taught novice putting together a high-...
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MCP7940 - power loss during time set
To set time in MCP7940 I should stop oscillator. If power loss will occur in this moment, RTC will not resume. Is there any way to overcome this problem ? Continues time is critical for my project.
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Regarding RTC drift
Basically there are two RTCs:
1.internal RTC
2.external RTC
Internal RTC has no battery backup whereas external RTC has CR2032 battery to maintain time in absence of power supply. For accuracy ...
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Deep sleep wake ESP8266 with DS3231 RTC alarm
I'm trying to use a DS3231 RTC to wake my ESP8266 at a specific hour, minute and second. My circuit is a very low power design.
I believe I need to reset my microcontroller (by momentarily pulling the ...
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RTC_RD_TIME: Invalid Argument error [closed]
When I try to read hwclock date and time manually it is working fine.
...
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RTC counter wrap mode
can any one plz help me out with the following queries
In synopsis datasheet for RTC we have one feature i.e Counter wrap mode enter image description here
my understanding for this feature -> RTC ...
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Can RTC IC detect power cut situation?
I have been making research about power down detection on Google. The only battery powered IC in my circuit is PCF85063 RTC IC.
Here @VoltageSpike says that it is possible with using RTC IC and ...
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Can't access RTC Alarm Registers for second time
Hi STM32F103 Programmers
I am fighting with my RTC. I have it working but have problems with accessing the Alarm registers for the second time. I can't find the reason why I can't.
I program the RTC ...
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PC: Which crystal is used for main clock? (X570)
I want to improve intrinsic (hardware) precision of windows/linux (OS) time (specifically, in my case it's AMD X570 platform), without relying on periodic correction via NTP servers. Common approach ...
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Why is the time lagging behind on the Renesas ISL1208 real time clock (RTC) in battery mode?
For a project I am using the ST M41T81 RTC but because of the parts shortage, I updated the firmware to support both the M41T81 and LS1208 RTC chips. The reason I am using the LS1208 is because the ...
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RTC on STM32 doesn't start running, except when a breakpoint is active
I use:
STM32L071K8U3
Segger JLink + Segger Ozone + SWD with 4 MHz
Cube Ide
External LSE or internal LSE, same problem.
I wrote firmware that displays the time using the RTC. To update the display, I ...
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Identify component RTC 10800
I’m a little stuck on this component, it’s on the incoming 230 V supply line to a battery charger circuit, so it should be a surge thermistor, but I can only find types of NTC or PTC, not an RTC.
Any ...
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External load capacitors on 32.768 kHz crystal oscillators
I am trying to design a circuit with the MCP79402 RTC. However, I do not understand why the crystal oscillators require external capacitors, and I am confused on how to calculate values for said ...
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Combined timer/RTCC [closed]
I have been using a Maxim DS3231 as a RTCC with its alarms used to "wake up" certain hardware.
Now I need to wake up the hardware periodically, say every hour, so I actually need a timer (...
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Symbol identification (J?)
I am looking into a part from a application guide titled How to Calculate UNIX ® Time Using a PIC18 Microcontroller and the MCP795W20 SPI RTCC. And there is a part that I'm not sure what it's suppose ...
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Do I need RTC while I'm using NTP?
We know computer and another device like microcontroller is not accurate in ticking clock comparing to wall clock that using cesium atom.
I heard RTC module is purpose to making accurate the ticking.
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RISC-V GD32VF103 battery backup domain
I'm not sure how the VBAT pin of the GD32VF103 RISC-V MCU should be connected, exactly.
The GD32VF103 User Manual states:
The Backup domain is powered by the VDD or the battery power source (VBAT) ...
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Can a memory backup supercap hold on for more than 2 weeks?
Most RTC chips have a VBATT input for backup power supply; besides a battery, you can use a supercap there, e.g. using the following scheme:
simulate this circuit – Schematic created using ...
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Are There Any Standards for RTCs, Similar to JC42 Temp Sensors?
When I place a temperature sensor on a board, I like to use a JC42-compliant temperature sensor. I know of at least half a dozen manufacturers that build these temperature sensors in exactly the same ...
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LiPo cell as RTC backup battery
I am wondering what is the sensible way of using the LiPo cell that powers a handheld device to also act as the RTC backup battery for the MCU. There is charging circuitry for the LiPo cell on-board ...
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Simple circuit to sample 120 VAC and yield 8.33 ms pulses
Have you noticed the lack of availability and prices of RTC chips lately? A simple DS1307 RTC is simply not available right now. Last year I purchased DS1307s for less than a buck. Now they are $4+ ...
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DS3231SN RTC -- timing between 1Hz SQW and clock seconds?
I don't think this is addressed in the DS3231SN datasheet but I may be missing something.
When the SQW output is programmed to output a 1Hz signal, is there a known / fixed phase relationship between ...
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I2C bus slave powered before raspberry pi master
I have a number of I2C slaves (PCF85063AT) connected a Raspberry Pi, which acts as master. For various reasons the I2C slaves are powered at all times, where the power to the Pi can be controlled on/...
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I2C via MCU works with FLAG_WRITE_READ but not FLAG_READ
I'm reading the date from an RTC via I2C using a SiLabs MCU. There are two different flag options, but only the 2nd one works.
I'm new to implementing I2C, what is happening on the wire that works ...
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Converting code with Boolean to a byte array
I am having a hard time understanding this code. I have code I am working on to sequentially flash the current 12 hr time on a single 7-seg display when you press a button.
I used a Boolean matrix to ...
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DS3231 Question
Can someone help me understand the differences between:
"Adafruit DS3231 Precision RTC Breakout" and one of these generic breakout modules, "DS3231 AT24C32 IIC RTC Module"?
Why I ...
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Arduino + DS3231 Wristwatch Help
I am a mechanical guy looking to expand my electronics skills. I would like to make a simple digital watch mainly for academic fun. Right now I am running into endless issues due to my inexperience. ...
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sniffing a 32.768kHz low-power oscillator
I'm troubleshooting a real-time clock and suspect that under certain conditions the oscillator stops. How could I check if it is running, especially when the RTC chip is on battery power? It is Maxim ...
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Pull-up resistors needed between DS3231 and AHT10?
I'm trying to create a datalogger using DS3231, AHT10, ESP-01 and MicroSD Module. So far I noticed that the AHT10 is returning wrong fixed readings: -50 for temperature and 0 for humidity. When tested ...
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Can a low side L-spike destroy a turned off microcontroller through its ground pin?
I am working on a low power project involving servo motors and an STM32 Bluepill MCU board and I was wondering if it was necessary to place a free-wheeling diode as shown in the schematic below (D1).
...
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Coin battery for powering the RTC while MCU power down: is safe for ATEX ZONE 2 or DIV2 in hazardous environment? The Box is heavy duty IP67 sealed
I wish to use RTC which keep powered by a coin battery (i.e. CR1225) while disconnected from +5V power. The box is heavy aluminum diecast with IP67 sealed. I was concerned about using coin batteries (...
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Is it possible to use the RTC alarm signal on the tamper pin in order to hold that value in a D flip flop? STM32 (bluepill)
I've been doing a lot of research concerning Low power modes for the STM32 (Bluepill) and I was wondering if I could power my board through VDD and then, right after going into sleep mode, I would use ...
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Diode OR with more than two sources
Is this type of system a good idea? I tried multiplexing two coin cells, one USB and one booster using four Schottky diodes (CUS10S30.) Schematic is given below.
The RTC does not work properly in this ...
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Looking for an extremely low power RTC module (and more!)
I'm working on a project called The Fifty Year Beep. The goal is to produce a battery-powered circuit that will beep once and only once fifty years from now. It is an art project of a kind, inspired ...
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