You could also write a pulse counter firmware for the PRU with only a 50KHz input it wouldn't need to be very optimized at all to catch every pulse. You could send a signal to the ARM every so often and catch that in your userspace program. Learn more. How to read the external timer counter on the BeagleBone Black?
Ask Question. Asked 4 years, 5 months ago. Active 4 years, 5 months ago. Viewed 2k times. So, I issued the following commands to load the proper cape and setup the pin as a timer :. I'm using the latest Ubuntu Linux for BeagleBone, kernel 4. Hanno Binder: This is a bare metal solution, I'm using Linux. Active Oldest Votes. Alex Hiam Alex Hiam 2 2 silver badges 7 7 bronze badges. As I'm using Linux 4. Second part looks interesting, but it looks to me that it's a lot of work to write a custom firmware for the PRU.
It only takes a minute to sign up. It can accept a wide range of clock frequencies and has a programmable prescaler allowing values from 1 to For example, it has a precision of 37ns when fed a 27MHz clock with a prescaler of 1 Table in the manual.
However, if you're using an operating system chance are it's already utilizing that timer and you'll be dependent on the operating system for timing. Depending on what you're trying to do, in addition to the dedicated timers listed in other answers you can use the embedded PRU Programmable Realtime Unit modules in this processor to do high speed timing.
Each core has a 32 bit cycle counter providing 5ns resolution. The effort required to configure and use the PRU will be much higher than using a dedicated timer. Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. High resolution timer on the BeagleBone? Ask Question. Asked 7 years, 11 months ago. Active 7 years, 11 months ago.Getting Started with the Beagle Bone Black
Viewed 7k times. Telaclavo 4, 16 16 silver badges 28 28 bronze badges. Active Oldest Votes. Austin Phillips Austin Phillips 1, 8 8 silver badges 9 9 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook.
Sign up using Email and Password. Post as a guest Name. Email Required, but never shown. The Overflow Blog. Featured on Meta. Feedback on Q2 Community Roadmap.For robotics, this means that three hobby servos can easily be controlled by the Beagle given nothing more than a simple level-shifting circuit, with no CPU usage to speak of.
Alternative approaches are possible. See BeagleBoardPinMux for more details on this procedure.
Automatically Setting the Beaglebone Black Time Using NTP
Obviously these lines should precede the line terminating the array. I found the above didn't work with the 2. Here is a nice description of how it is done. To briefly summarize this and simplify significantlythe general-purpose timer is a continuously-incrementing counter that can be configured to toggle the PWM output high when a certain value is reached, and low when it overflows.
By adjusting the first number the duty cycle can be set. Setting the value the counter starts at can be used to set the frequency of the PWM. The start addresses of these blocks for the timers on the BeagleBoard are listed below. The best way to interact with the timer registers is to use the kernel module in development as a Google Summer of Code project this driver is currently, as of Julyin development. It is made available under the LGPL 2. These links appear to be broken now.
You can get to a version of the PWM code by following the instructions here. It describes how to load code from git github. Information regarding compilation of this program is not included in any README file so to ease compilation problems use the following.
Keep in mind this has been only tested when compiled on the beagleboard and not cross-compiled though it should still shed light if you have problems. This is caused because the library does not enable the PWM clocks and you are not allowed to access them until this is done. From eLinux. Jump to: navigationsearch. Category : ECESpring Navigation menu Personal tools Log in Request account.
Download the lastest Debian image from beagleboard. The "IoT" images provide more free disk space if you don't need to use a graphical user interface GUI. The Debian distribution is provied for the boards. The file you download will have an. This is a compressed sector-by-sector image of the SD card.
Use Etcher to write the image to your SD card. Etcher will transparently decompress the image on-the-fly before writing it to the SD card. The latest Debian flasher images automatically power down the board upon completion. This can take up to 45 minutes. Power-down your board, remove the SD card and apply power again to finish. Most Beagles include a USB cable, providing a convenient way to provide both power to your Beagle and connectivity to your computer.
If you provide your own, ensure it is of good quality.
Alternatively, your Beagle may have a barrel jack. If you are using your Beagle with an SD microSD cardmake sure it is inserted ahead of providing power.
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Most Beagles include programmed on-board flash and therefore do not require an SD card to be inserted. Within a minute or so, you should see the other LEDs blinking in their default configurations. If connected via USB, a network adapter should show up on your computer.
Your Beagle will reserve The access point password defaults to "BeagleBone". If your computer supports mDNS, you should see your Beagle as beaglebone. Non-BeagleBone boards will utilize alternate names.
Multiple BeagleBone boards on the same network will add a suffix such as beaglebone The below table summarizes the typical addresses and should dynamically update to indicate an active connection.A watchdog timer WDT is used by a computer system to identify and recover from unexpected interruptions.
Watchdog timers are especially important in remote and embedded applications. Fortunately, the BeagleBone Black comes equipped with built-in watchdog timer functionality. Our new Inspire tutorial provides step by step instructions for accessing and activating the BeagleBone Black watchdog timer. The BeagleBone Black has an embedded watchdog timer that can be very useful in providing a reset function.
This enables the watchdog, and it must now be periodically accessed. The initial period is about 60 seconds. Your application program, should then access the watchdog timer to ensure that under normal operation the time interval is satisfied. Failing to write to the watchdog will cause a forced system reset. This is what we would like to happen if our program has become unresponsive.
Wait about 60 seconds and your BeagleBone will reset and reboot. On the other hand, if you issue the command again, before the timer has elapsed, the reset will be delayed further. These simple steps will help you test the watchdog timer. A simple method is to regularly issue a system command from the programming language chosen. BoneScript also has a simple method to automatically run a program.
The implementation will vary based on the application needs. Save my name, email, and website in this browser for the next time I comment.
View Larger Image. A watchdog timer will: Allow enough time for the system to boot before triggering a reset. Reset the system, if the program becomes unresponsive fails to report on time. Testing The Watchdog To test the watchdog, simply write to the watchdog. A simple python example:! Share This Story!On my current distribution the Beaglebone Black does not come with a working NTP installation in order to set the time.
If you wish to set the time you could do it on a once-off basis…. Which is quite some time ago! I noticed this because I did a git commit and in the github status it said that I did the update 13 years ago! However, if you reboot your Beaglebone the time will be back to the good old year So, we need a way to update this each time the Beaglebone boots. Next, we need to install the ntp software on the Beaglebone black — so, at the command prompt I am using Angstrom here :.
Next, find a NTP server that is close to your location. For Ireland I get:. If you only want to allow machines within your own network to synchronize their clocks with your server, but ensure they are not allowed to configure the server, set the restrict value as above.
Important — make sure that you comment out the server and fudge lines or the server will sync to itself! You can copy the file directly or use one of the presets. The advantage of this over copying the file is that you can see the timezone that was set when you ls:.
However, and importantly on the Beaglebone black you have to modify the second service to:. The time will not automatically update unless you make this change. Most operating systems and hardware of today incorporate a time-of-year TOY chip to maintain the time during periods when the power is off.
When the machine is booted, the chip is used to initialize the operating system time. After the machine has synchronized to a NTP server, the operating system corrects the chip from time to time. In case there is no TOY chip or for some reason its time is more than s from the server time, ntpd assumes something must be terribly wrong and the only reliable action is for the operator to intervene and set the clock by hand.
This causes ntpd to exit with a panic message to the system log. The -g option overrides this check and the clock will be set to the server time regardless of the chip time. However, and to protect against broken hardware, such as when the CMOS battery fails or the clock counter becomes defective, once the clock has been set, an error greater than s will cause ntpd to exit anyway.
Thanks to Louis Thiery in the comments below — he pointed out that the RTC Time was still out after you perform the steps above. I have made one additional change to the configuration and it seems to do the trick — It is probably a bit of a hack!
You can see here that the RTC time is now the same as Local time and all appears to be in order — And, in case you are concerned, yes, it is actually am, time for my bed! Just a quick note in the latest BeagleBone black image they automatically sync the time. Thanks, that is good news. Instead of.Microcontroller Tutorials.
I2C is a popular communications protocol and is used by a lot of sensors and devices.
Beaglebone Black I2C Tutorial
Those addresses with UU are reserved address. Noticed there is a The first hex number is the I2C device address followed by the specific data address and the byte to be written.
To read the registers from the device connected to the I2C bus, the i2cdump command can be used:. Follow this blog for updates! I am facing one problem while doing i2cset and i2cget. But in different board. This program can confuse your I2C bus, cause data loss and worse! I am using one i2c test application to receive i2c 1 or 2 bytes. After running which only i2c slave will be attached to i2c bus!
And also running the application changes the register values,which is read using printk in the driver. You're device and board is quite different to what I'm presenting here but normally, a 0xFF reading indicate a timing mismatch between the master and the slave device.
Maybe there is something wrong with the wiring because one reason for mismatches are voltage spikes or not reaching voltage thresholds for both low and high pulses. I will probe address range 0xx Ah yes, it is expected. Sorry I thought you are using a device other than BBB. Also, I don't think the address of your device is 0xBE. So 0xBE should be 0x5F which is within range.
What a great tutorial. Did you have to pull up the I2C connection to be able to detect the device? Thanks for that Roland, It seems as though my device isn't being picked up with i2cdetect and I was suspecting that it would require a pull up resistor but unsure at this stage.
What would you do to test that? I am trying to hook up the BeagleBone to be able to send i2c commands to the uC onboard the evaluation board and toggle the LED's. It still seems confusing as to how one can write a program to write to an I2C slave device and control.
Command line is great but writing a script that could be run and looped is something that I am still looking into.