On Fri, Dec 2, 2016 at 2:37 PM, acheesehead <[email protected]> wrote:
> Thanks William. I'll try out your instructions on Mon. > One thing I did not mention last night was that I did all this one a beaglebone black running . . . william@beaglebone:~$ cat /etc/dogtag BeagleBoard.org Debian Image 2016-10-30 william@beaglebone:~$ uname -r 4.4.27-ti-r62 So, someone mentioned in the last couple of days ( I think ) that they're using a 3.8.x kernel. A couple of concerns with this is that a) the overlays as described by me may not work the same. Meaning, I do not recall if 3.8.x overlays are slightly different or not. Through the source, or in how dtc compiles the source into "binaries". b) The sysfs file entries are possibly going to be different. Honestly, I could not say for sure, because last night was the very first time I've setup 1-wire on the beaglebone. I just know / knew how to modify the overlay's source in order for it to be proper. How to wire up the sensor through a buddy of mine( someone with 35+ years electronics design experience ). Here, see everyone on the web is saying to run a 4.7k resistor between Vdd, and DQ on the sensor. Even if you're externally powering the sensor. Where I've been told this is not necessary, and that the resistor is only needed if you're going to parasitically power the sensor through the DQ pin. Which my buddy does not seem convinced that this sensor can be powered through a Beaglebone GPIO. So "erroring" on the side of caution least I burn out a GPIO pin, or worse yet the processor. I opted to power via an external power source. Also reading the datasheet I noticed the input voltage range for the sensor is something like 2v8 to 5v6 ish . . . I just powered the sensor straight off P9.5( 5v ). Indeed, in the end, it seems to work perfectly fine this way. But I did not double check the temp output to make sure it was accurate. I am however reasonably convinced it's fine. I'll double check later with another kind of temperature sensor that I know is accurate within a degree or two. Close enough for me . . . we even have some K-type thermocouplers here( MAX31855 ) that are very accurate if it ever comes to that. I haven't done SPI on the beaglebone yet though . . . Anyway . . . The image I'm using is the one Robert says is the latest Jessie "release" image that will be shipping with the BBGW's soon( I believe ). Everything else as far as I can remember is pretty stock. Except I've installed a few Debian packages that should have no bearing on this subject at all ( build-essential, git, nfs-client. acpid, maybe i2c-tools, etc ). Wait, one thing I did change in /boot/uEnv.txt: ##BeagleBone Black: HDMI (Audio/Video) disabled: dtb=am335x-boneblack-emmc-overlay.dtb I do not think this overlay is loaded by default on the stock image. For the pin I chose, I do no think it's related to hdmi at all. But if you're going ot use a different pin, you should double check to make the pin does not conflict with the hdmi pins. Or some other board function. Picking I2C0, or I2C2 pins would also not work out very good. As well as the eMMC pins, if you're running off the eMMC . . . standard double check everything. -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CALHSORocN_O4KkgnykkWDy-h9%3DYoc%2BxhtWH52-ysaM7_-%2BLN1g%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
