> Date: Thu, 30 Apr 2015 08:28:23 -0400 > From: Paul W Panish <ppan...@panishnet.com> > Subject: Re: [Owfs-developers] Temperature sensitive bus timing using > DS18B20
> I'm running Debian Linux on a Beaglebone Black. I've done nothing > special for a kernel build, and I've built owfs using defaults, so the > configure output indicates that W1 is enabled. My application starts at > boot and runs as root with full permissions. I'm also running on a BBB, with the default repo version of OWFS for Ubuntu 14.04. But I'm using one of the GPIO lines as my 1-Wire bus. Nothing happens on the bus for me until I manually start the 1-Wire "device tree overlay": --> The compiled w1-00A0.dtbo file must be in /lib/firmware/: /lib/firmware/w1-00A0.dtbo 968 Mar 19 15:48 --> When you give the echo command you omit the "-00A0.dtbo" part! --> The sudo and sh tricks don't work for me - full su is required: echo w1 >/sys/devices/bone_capemgr.9/slots --> The 1-Wire bus is instantly active, but no actual results are reported unless "server: w1" is in owfs.conf. ubuntu@arm:~/Lpkg$ cat /sys/devices/bone_capemgr.9/slots 0: 54:PF--- 1: 55:PF--- 2: 56:PF--- 3: 57:PF--- 4: ff:P-O-L Bone-LT-eMMC-2G,00A0,Texas Instrument,BB-BONE-EMMC-2G 5: ff:P-O-- Bone-Black-HDMI,00A0,Texas Instrument,BB-BONELT-HDMI 6: ff:P-O-- Bone-Black-HDMIN,00A0,Texas Instrument,BB-BONELT-HDMIN 7: ff:P-O-L Override Board Name,00A0,Override Manuf,w1 ubuntu@arm:~/Lpkg$ dmesg | grep "w1" [ 163.085350] bone-capemgr bone_capemgr.9: part_number 'w1', version 'N/A' [ 163.085456] bone-capemgr bone_capemgr.9: slot #7: 'Override Board Name,00A0,Override Manuf,w1' [ 163.086507] bone-capemgr bone_capemgr.9: slot #7: Requesting part number/version based 'w1-00A0.dtbo [ 163.086532] bone-capemgr bone_capemgr.9: slot #7: Requesting firmware 'w1-00A0.dtbo' for board-name 'Override Board Name', version '00A0' [ 163.088181] bone-capemgr bone_capemgr.9: slot #7: dtbo 'w1-00A0.dtbo' loaded; converting to live tree That's the only "w1" usage I've seen. Apparently your version doesn't require any of that complexity? And does not produce any of those messages? I always thought my "echo" command was starting w1 action. Maybe it is just redirecting it from some other default interface to my GPIO line? If you don't explicitly connect w1 to a particular hardware device, how would it know where to look for 1-Wire connections? > Checking dmesg I can find no instance of w1 (or W1) > when the LinkUSB device is registered or at any other time. Seems odd, since my connection of w1 to the GPIO pin produces obvious messages. I also see mention of "w1" every time the reading fails: [516795.923561] w1_slave_driver 28-000000884d88: 18S20 doesn't respond to CONVERT_TEMP. [1209223.294902] w1_slave_driver 28-000000884d88: 18S20 doesn't respond to CONVERT_TEMP. [1217623.893153] w1_slave_driver 28-000000884d88: 18S20 doesn't respond to CONVERT_TEMP. --> I don't understand these. --> the bus reports all "ff" for the first "crc" output line, but OWFS always reports "-62" regardless of the values in the second line: --- Fri Jul 04 2014 13:55:01 GMT-0700 (PDT) c8 01 4b 46 7f ff 08 10 3f : crc=3f YES c8 01 4b 46 7f ff 08 10 3f t=28500 Fri Jul 04 2014 14:00:02 GMT-0700 (PDT) ff ff ff ff ff ff ff ff ff : crc=c9 NO c8 01 4b 46 7f ff 08 10 3f t=-62 Fri Jul 04 2014 14:05:02 GMT-0700 (PDT) cc 01 4b 46 7f ff 04 10 67 : crc=67 YES cc 01 4b 46 7f ff 04 10 67 t=28750 --- > The kernel has it's own onewire subsystem, made for accessing battery > and backlight controller chips on some notebooks. But it's a > full-featured system and it always *CLAIMS* all the onewire host > adaptors which are present in the system. Does this happen even on the BBB? It certainly didn't find my GPIO connection automatically! Is there some way to inquire what adapters it has found? >> I'm also confused by your "kernel driver and OWFS accessing the host >> adaptor at the same time" line. Doesn't "host adaptor" imply USB or >> some other hardware beyond the simple hardware I/O line that w1 >> accesses? Maybe w1 could be considered the conceptual equivalent of >> USB or some other host adaptor, like it appears in my owfs.conf, but >> accessing a totally different hardware bus? Or have I missed some >> basic concept here? Obviously what I'd missed is that the w1 mechanism is separate from my GPIO connection to 1-Wire. I guess my GPIO could be considered a "host adapter", one of several that w1 could connect to. Thanks for helping me think through this! Loren | Loren Amelang | lo...@pacific.net | ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y _______________________________________________ Owfs-developers mailing list Owfs-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/owfs-developers
