Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

Questions tagged [system-clock]

The system clock controls timekeeping on a computer. The Raspberry Pi does not have a system clock, although it [may be possible to use an external device](http://raspberrypi.stackexchange.com/questions/266/how-can-i-keep-system-time) to keep time.

1
vote
2answers
50 views

What is the memory in the DS3232 RTC for?

I'm looking for an RTC to use with my Pi and came across the Maxim DS3231M. I also saw a similar model on Maxim's website, the DS3232M, which comes with 236 bytes of SRAM. The DS3231 seems to be a ...
0
votes
1answer
29 views

Raspberry pi 2 model b system clock ppm

I have a Raspberry Pi 2 model B and a RTC (precision 1 ppm) hooked up with, without Internet conneciton. When the RPi is power off is the RTC the responsible to keep the current hour but when the RPi ...
1
vote
0answers
21 views

How do I interface with the “cprman” clock manager from another kernel module?

It's relatively simple to control the clock manager registers. I've found a set of values, and have C code that writes the desired values to the clock manager registers. This works well; that part ...
1
vote
1answer
86 views

Do some Pi Zeros need to run slow so they don't freeze up after a while?

I've used a number of Pi Zeros and some seem to need to run slow. The symptom is they freeze after a number of hours or a day or so. I'm using the Zero not the Zero W. I'm running the camera. I've ...
1
vote
1answer
123 views

What are the vcgencmd measure_clock 26 and 50?

There are 2 clock sources that are not officially (?) listed with a string id available to the vcgencmd measure_clock command. # for i in {0..255}; do vcgencmd measure_clock $i; done | grep -v "=0" ...
1
vote
1answer
99 views

Panel settings: System panels all aligned left

I mucked with my panel settings using a janky mouse, and somehow removed a setting that had my system (clock, wifi, sound, etc.) on the right, and the Menu + custom apps on the left. Now everything's ...
1
vote
3answers
115 views

Bridge between Web&GPIO

For an alarm clock I am trying to have the interface in HTML and CSS and I need the GPIO pins for PWM-output (3 channels and some digital, possibly also "analog" inputs). I want a neat web-interface, ...
5
votes
5answers
3k views

Do I need an RTC if my Raspberry Pi is continuously connected to the Internet?

How accurate would the time on my Raspberry Pi 3 be if it is continuously connected to the Internet, but without an RTC?
1
vote
1answer
34 views

Syncronize a datetime beetween Raspberry and a SmartPhone

I have an offline webserver on my raspberry pi. How would I be able to get the date from a device to my raspberry pi?
2
votes
1answer
1k views

Windows 10 IoT does not automatically use the Real Time Clock module to automatically update the system time

bought a brand new Raspberry Pi 3 DS3231 RTC Module and integrated to correct gpio pins as it should be. But somehow Windows 10 IOT seems not detect this module. than attempted to follow follow ...
3
votes
2answers
6k views

Set manually datetime raspberry

I have a project that uses Raspberry in offline mode. We know it doesn't have a clock when it powers off. The router, even in offline mode, have a clock when it power off. So, i have 2 questions: 1 -...
1
vote
1answer
201 views

System time problem on Raspberry Pi after power outage

If have a raspberry pi on Raspbian running a home automation server. That server depends upon accurate system time on the raspberry pi. When I have a power outage for a bit of time and then the ...
0
votes
1answer
28 views

Edit the UART communication protocol

Is it possible to manipulate the bytes on a bit level prior to sending through the hardware UART, or do I have to implement a software version (bit-banging)? I was thinking of changing the clock ...
2
votes
1answer
1k views

Sync system clock with GPS time on `systemd-timesyncd`

With the arrival of Raspbian Stretch, ntpd is replaced by systemd-timesyncd. I used to be able to sync the system clock with GPS time by adding a few lines to /etc/ntp.conf. Anyone has any clue how to ...
2
votes
0answers
62 views

How to manually adjust system clock for testing purposes

I have written a Python script that is set to run different functions at different days/times. I would like to test it by setting the system clock to 1-2 minutes before the dates/times that the Python ...
0
votes
1answer
435 views

Access Raspberry Pi3 Timer using Python

there is a way to get access and then configure Raspberry pi Timers using a Python? I saw some code to do that but it always be in C. Like here [BareMetal] Timer on Raspi All this I need to send ...
1
vote
0answers
71 views

rtc ds1307 module loosing time

I am trying to get the rtc i2c ds1307 module working under Raspbian Jessie. I followed these guide to let the raspberry recognize the module and set it up. Fortunately everything works great. I can ...
0
votes
1answer
128 views

Program gets wrong time when loaded on boot

When I've booted my Raspberry Pi 3 into Raspbian, I've setup the /etc/profile to load a program though mono. However, the program now reports the wrong time (An hour behind on the previous day), ...
4
votes
2answers
1k views

Cycles per instruction

I have a default raspberry pi running raspbian, assuming it’s running at 700MHz. I’d think that every instruction would take only one or a few cycles at most. In my experiments that doesn’t seem to be ...
1
vote
1answer
163 views

Node.js Application Not Running

So, I've made a Twitter bot using node.js, slightly modified from this guide, which is supposed to send a tweet every two hours (using Javascript's setInterval() function). Running on a Windows 7 ...
1
vote
2answers
220 views

How do you force wiringPI library to use local time instead of UTC time?

I am running Pi 3 along with Real-Time Clock chip ds1302 and using wiringPI library to read and set date and time to and from ds1302 chip. After I set my Pi's system date and time to local date and ...
2
votes
1answer
102 views

What would cause pi's system date and time to drift while plugged into a power source and not on the Internet?

I have two Pi 3 running at the same time with my program being executed while both are plugged into a power source with current date and time and not connected to the Internet. Couple of days later I ...
4
votes
1answer
2k views

Raspberry Pi 2: Sync clock with local server?

I have 10 Rpi2s with me and I have created a setup like this. My Windows system clock is set to local time once and I expect it to be powered at all times. It is a Workstation class system and it acts ...
1
vote
1answer
2k views

Does Raspberry PI work with UTC time by default?

I have a program that runs on Raspberry PI that is completely depended on localtime. Otherwise, it will completely FAIL. On a Linux system like Magiea, it doesn't have any issues running as it should. ...
1
vote
1answer
467 views

Multiple clock outputs from Rpi

I want to make use of the clock of rpi. How can I do it? On an arduino it would have been as easy as setting up an TCCR and the respective pin would give the required clock signal. I require two clock ...
1
vote
0answers
113 views

Synchronize Pi Camera and LEDs

I have a Pi Camera (NoIR) and two sets of LEDs, A and B. The two sets of LED are different in position and wavelength. I want record video with the Pi Camera so that any consecutive frames be lit by ...
1
vote
0answers
13 views

How to enable Digital Clock Preferences in LXDE [duplicate]

I am trying to set the system time to Local time rather than UTC. The LXDE Digital Clock shows UTC and an application I am running remotely and viewing in Epiphany is logging UTC time stamps rather ...
8
votes
4answers
23k views

How to change the clock to 12-hour format in Raspbian?

By default, Raspbian displays a 24-hour clock: Normally, LXDE provides an option to change the clock format by opening Panel Preferences, selecting "Digital Clock", and clicking Preferences. However, ...
1
vote
1answer
775 views

Raspberry Pi B+ CPU clock manipulation

Is it possible to manipulate rPi B+ with ArchLinux system clock, I need to slow it down because of power management purposes.
1
vote
1answer
828 views

How to set real time clock in Raspberry PI instead of setting fake clock

I would like to know how to set Real Time Clock instead of Fake Clock in Raspberry PI. Hope you guys could help me out with it as soon as possible.
2
votes
1answer
124 views

Under what conditions is the system clock running?

The Raspberry Pi has no battery powered hardware clock, so it needs to fetch time via NTP and store it via fake-hwclock to not start at 1970 again after a power-loss. When the device is running the ...
3
votes
3answers
415 views

When do I need accurate time via NTP?

The Raspberry Pi has no hardware clock, so the OS has to fetch the date and time every time when it boots if one wants accurate time. Do I need accurate NTP time at all and what use cases require it? ...
11
votes
3answers
872 views

Will RPi suffer from the Y2K38 bug?

Just out of curiosity, what will happen to RPis Model A and B on January 19, 2038 in 3:14:07 AM GMT? Are they affected by the Y2K38 bug?
2
votes
3answers
6k views

set system clock to value received from GPS

I've got a USB GPS receiver permanently attached to my raspberry pi. At boot time, I would like raspbian to wait until the GPS has a signal, then set the OS's time to whatever the GPS says. I've ...
7
votes
4answers
18k views

After reboot, my RPi is one hour off — How to adjust for Daylight Savings problems?

The electricity to my apartment went out a few days ago. I use my RPi to record data and store it in a database. I've just learned that the time for all my data has been off by an hour because the ...
3
votes
2answers
13k views

How to get the exact clock speed at the raspberry pi is running?

As per the specification. If you power the raspberry pi from the USB port from PC,It will run at half speed of what it can achieve. But when you power it from the external source then it runs at full ...
5
votes
4answers
6k views

Keeping System Time Without Network

Is there a way to sync the clock with the internet (as easily done) upon one startup, then shutdown, move the computer to another place WITHOUT an internet connection, and get a reasonable time? I'm ...
1
vote
2answers
780 views

Could the raspberry pi be used for stimulus presentation in psychological experiments?

I am a cognitive psychologist / neuroscientist. In a lot of the experiments that I run I have participants - mostly undergrads - sit at a computer and respond to certain combinations of visual stimuli....
1
vote
2answers
4k views

Configuring to read RTC at boot time

I have added an RTC to the I2C bus of the Raspberry Pi. If I follow the steps mentioned here (I am using the DS1307 RTC IC), I can run hwclock and read the time. root@raspberrypi:~# modprobe rtc-...
16
votes
3answers
4k views

How accurate is Raspberry Pi's timekeeping?

I realize that since Raspberry Pi doesn't have a hardware real-time clock built in, some issues with accurate timekeeping may present themselves, even when persistence across reboots is not a ...
5
votes
2answers
376 views

System time coming through SSH?

I have a setup where my Pi is connected to power and to my router, and I then set up a connection with my laptop through SSH (a good setup for saving space, if you don't have a lot). I fired up my Pi ...
41
votes
5answers
55k views

How can I keep system time?

I know that Raspberry Pi does not come with a system clock to save money. How can I keep system time though?