On Mon, Dec 5, 2016 at 7:30 PM, acheesehead <[email protected]> wrote:
> Tried your workflow today without success. Everything is OK up to the > lsmod | grep w1 step. I only get the w1_gpio entry. I am not a Linux kernel > expert, so I don't know how to troubleshoot why the other entries aren't > showing up. > > I didn't see any activity on the oscilloscope either. > Then, you must be using a 3.8.x kernel. Right ? But here are the modules needed at least on a 4.x kernel: william@beaglebone:~/dev/bb.org-overlays$ lsmod |grep w1 w1_therm 4886 0 w1_gpio 3764 0 wire 35398 2 w1_gpio,w1_therm All three of those need to be loaded in order for the DS18B20 to work. So, try manually loading those via modprobe. SO let's take a look at a rPI blogpost: https://www.modmypi.com/blog/ds18b20-one-wire-digital-temperature-sensor-and-the-raspberry-pi Much of this blog post is going to be RaspberryPI centric. *dtoverlay=w1-gpio, */boot/config.txt, etc. However if you scroll down to the *"Programming" *part of the blog post. This person talks about loading the required kernel modules( also note that kernel version is 3.6.11 ) Using modprobe. So if you run those two modprobe commands, and then list the contents of /sys/bus/w1/devices: *william@beaglebone:~$* ls /sys/bus/w1/devices/ 28-00000647ddf6 w1_bus_master1 And you get output like the above. 1-wire *is* working, and the 1-wire master ( beaglebone ) has detected a 1-wire slave device. It's working. However, if you load both the above 1-wire kernel modules, and there is nothing in /sys/bus/w1/devices, then something is wrong. I'd have to say at this point, if you do not get an error about a missing module, that you have your pin muxed incorrectly, or not properly connected to the pin. Now if you get an error on the command line from trying to load either of those two 1-wire modules. Chances are pretty good you haven't compiled in the given proper 1-wire support. In fact, I do believe there is a whole section in menu-config for 1-wire devices. You may actually have to recompile your kernel with support for the DS18B20 1-wire device . . . Another issues between 4.x, and 3.8.x kernels is that device enumeration was different for some devices. So . . . It is entirely possible, in your overlay, that the GPIO bank you're passing in as parameters is off by one. How can be test for this ? On 4.x kernels . . . *william@beaglebone:~$* ls /sys/devices/platform/ocp 40300000.ocmcram 48042000.timer 480ca000.spinlock 49800000.tptc driver_override 40302000.ocmcram_nocache 48044000.timer 4819c000.i2c 49900000.tptc modalias 44e07000.gpio 48046000.timer 481ac000.gpio 49a00000.tptc ocp:l4_wkup@44c00000 44e09000.serial 48048000.timer 481ae000.gpio 4a100000.ethernet of_node 44e0b000.i2c 4804a000.timer 481d8000.mmc 4c000000.emif power 44e35000.wdt 4804c000.gpio 48200000.interrupt-controller 53100000.sham subsystem 44e3e000.rtc 48060000.mmc 48310000.rng 53500000.aes uevent 47400000.usb 480c8000.mailbox 49000000.edma 56000000.sgx *william@beaglebone:~$* ls /sys/devices/platform/ocp/44e07000.gpio/gpio/ gpiochip0 And the very first gpio address entry in this case was the lowest gpio bank. So, if you investigate the equivalent directory in 3.8.x, you should be able to check all gpio banks, to see what the actual lowest gpio bank is. Do also keep in mind that /sys/devices/platform/ocp/ will be different in 3.8.x. So you'll have to poke around a bit. Unless someone else posts here and gives you the proper path. I don't remember what it is. Anyway, there is another option. You can upgrade your kernel to a newer version. Which, yes, will probably mean you'll also have to either flash a newer image, or run a newer image from sdcard. -- 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/CALHSORqTRB%3D%2BsAjP81PvqSyZ2xid8Z58rgzzC_3ZtBAG0CK1Mw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
