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Beaglebone PRU GPIO example

Executive SummaryIf you're just trying to do ordinary GPIO on your beaglebone, this is not the page you're looking for.This is about how to use certain GPIO pins on the beaglebone using the two...

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Beaglebone PRU DDR memory access

Here's some C and PRU assembly code I wrote to see how fast the PRU can write to system (DDR) memory. // Loads a .bin file into a BeagleBone PRU and then interacts with it // in shared PRU memory and...

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BeagleBone maximum PWM frequency

Using a PWM channel to get square waves (don't care about duty cycle) from my BeagleBone, looks like I can get up to 50MHz with:root@beaglebone:~# echo 10 >...

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Closeups of a LED printer head

I picked up some printer heads for an Okidata LED printer and checked them out under the microscope.   This ebay auction shows what the complete head looks like.  An LED printer is basically a laser...

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BeagleBone Black and Green microSD and onboard flash performance

Looks like I get about 4.3MB/sec when writing to the onboard flash on my BeagleBone Black, and about 7.1MB/sec when writing to a 64GB Sandisk Ultra 64GB microSD card.On BeagleBone Green, I get 9.4MB/s...

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BeagleBone Black/Green bus speeds

USB Host (big type A jack): 20MB/s writing to a Seagate USB3 2TB portable (spinning) hard disk (required plugging a 5V 4A power supply into the BeagleBone Black's power jack).  On BeagleBone Green, I...

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Getting BeagleBone to recognize wifi adapters by upgrading the kernel

My beaglebone black wasn't recognizing my wifi adapter.  apt-get update ; apt-get dist-upgrade didn't help, and I noticed that it wasn't upgrading the kernel.Looks like the way to get kernel updates is...

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BeagleBone Access Point (and working around udhcpd)

Warning: it's easy to screw this stuff up and lose the ability to ssh into the beaglebone when you reboot.  Usually it was as simple as manually setting the IP address on my laptop, but you may not be...

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BeagleBone DMA notes

I've been transferring data between the BeagleBone's PRUs and main memory.  If I use the PRU's SBBO instruction to store a range of PRU registers to main (DDR) memory, I find that I get around 600MB/s...

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Connect beaglebone black to android via USB OTG

With the right USB OTG cables, I was able to connect my Nexus 5X to a beaglebone black and a beaglebone green.  I had to try several cables before the beaglebone would power up; I suspect it's the...

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Beaglebone black PWM minimum frequency

By trial and error, I just figured out that 1 billion is the longest period you can set for (at least this particular) PWM channel. root@beaglebone:/sys/devices/ocp.3/pwm_test_P9_31.13# echo 1000000000...

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Adafruit_BBIO bugs

First bug was mine.  I was doing "import Adafruit_BBIO as GPIO" instead of "import Adafruit_BBIO.GPIO as GPIO".  That gave this error once I started trying to use it:$ ./test.pyTraceback (most recent...

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Which GPIO pins work with Adafruit_BBIO

Working with the Beaglebone can be really frustrating.  There are a lot of buggy libraries and incomplete docs, and the Sitara chip is really complicated, overloading its pins to do lots of different...

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SeeedStudio Xadow with Ubuntu

Seems like every time I try to use the Xadow board, I have to spend hours getting it to program via the Arduino IDE.  This time, the solution seems to have been putting this in a file called...

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Connecting BeagleBone to newer Android Nexus phones (like Nexus 5X and Nexus...

Update: Huh, I just discovered that this exists: Settings > developer options > networking > select USB configuration > RNDIS (USB ethernet).  But it doesn't seem to work.  So I suspect the...

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BeagleBone to Android via USB Serial

As I mentioned in my last post, BeagleBone uses the Linux g_multi kernel module so that when you plug it into a PC, it appears to be a USB hub with USB-serial, USB-ethernet and USB storage devices...

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Supernight 5050 RGB LED string teardown

I've been having fun with this RGB LED string from Amazon with 300 5050 LEDs in a 16.4ft string.One bug: after using it for a few minutes, it seems to have swapped the red and green columns of colored...

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Measuring spirit level accuracy

I have a cheap Stanley 24-inch level like this one:The other day I noticed it didn't seem to be very accurate.  I checked by flipping it end for end on my workpiece, and sure enough the bubble settled...

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NVidia Jetson TX1 raw bayer frames via v4l2 via /dev/video0

The NVidia Jetson TX1 dev kit comes with a 5MP camera and a bewildering array of different libraries for accessing it.  One of the routes is using v4l2 through the /dev/video0 device.  This route only...

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Brass hammer from hex bar stock

My friend likes to make wooden mallets: So I thought he might get a kick out of making one with a brass head.  Here's the head so far.  (he's still thinking about what to do for a handle). This much...

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Compile NVidia Jetson TX1 kernel on device

There are lots of threads about problems compiling new kernels for their Jetson TX1 boards.  A lot of the issues seem to be related to the cross compilation environment.The TX1 is pretty beefy, so I...

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California Air Tools sucks

I bought this California Air Tools CAT-4620AC air compressor over a more respected brand like Makita because it's supposed to be so quiet. They claim it's only 70dB, about the level of a spoken...

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Home made cold stone ice cream

I was daydreaming about 3D ice printers, and it occurred to me that I might be able to make Cold Stone style ice cream if I put a big chunk of metal in the freezer.My first thought was to use steel,...

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Teardown: Miller RFCS RJ45 tig welding foot pedal

[Gallery with hi-res versions of the photos shown here]Tig welding pedals are expensive, mostly over $100.  Miller wants $150 for the RFCS-RJ45 pedal that goes with the Multimatic 215, and $600 for...

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Longs Motor DM542A idle current bug

Stepper motor drivers like this one usually have a jumper (that's usually SW4) that sets idle current.  So if you haven't sent any pulses in a while, rather than cooking your stepper by holding full...

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