> > *Hi,* > > *testing different kind of sensors/modules provide the change to work with the several buses the BeagleBone Black has.*
Irreverent . . . *Now, I'm playing with an analog light sensor connected to an ADC which > communicate with BBB through SPI bus. * > *So, the first step I need to do is enable the SPI. Then, test SPI with > loopback example. And finally, build the code to read from the ADC the > light sensor data.* > The first thing you need to do, is understand how your device works. Which is regardless to how / what SPI *is*. *To enable SPI0, I have followed this guide, SPIDEV > <http://elinux.org/BeagleBone_Black_Enable_SPIDEV>. During the guide steps > implementation I have found some doubts/issues, so I will explain the > procedure I has followed with its results in order to get the more precise > help as possible.* > - *Create and Edit: BB-SPI0-01-00A0.dts* Excuse me, What ?! Ok, first of all, what you need to understand is what SPI *is*. Passed that, you need to understand how to communicate with your device *over* SPI. After that, if you still have questions about SPIdev, I'm sure someone will be glad to help. > On Fri, Oct 16, 2015 at 4:30 AM, <alvjo...@gmail.com> wrote: > Hi, > > testing different kind of sensors/modules provide the change to work with > the several buses the BeagleBone Black has. > > Now, I'm playing with an analog light sensor connected to an ADC which > communicate with BBB through SPI bus. > So, the first step I need to do is enable the SPI. Then, test SPI with > loopback example. And finally, build the code to read from the ADC the > light sensor data. > > BeagleBone Black has: > > - OS: Debian > - Kernel: 3.8.13-bone78 > - Kernel version: #1 SMP Sat Sep 26 09:11:50 UTC 2015 > > To enable SPI0, I have followed this guide, SPIDEV > <http://elinux.org/BeagleBone_Black_Enable_SPIDEV>. During the guide > steps implementation I have found some doubts/issues, so I will explain the > procedure I has followed with its results in order to get the more precise > help as possible. > > 1. Create and Edit: *BB-SPI0-01-00A0.dts* > 2. Compile: *BB-SPI0-01-00A0.dts* > 3. Copy, *BB-SPI0-01-00A0.dtbo*, to: */lib/firmware/* > 4. Enable the Device Overlay Tree: > - *echo BB-SPI0-01 > /sys/devices/bone_capemgr.*/slots* > - At my system '*' is '9'. > 5. Edit: */boot/uboot/uEnv.txt* file to add next line: > - *optargs=quiet drm.debug=7 capemgr.enable_partno=BB-SPI0-01* > 6. Reboot. > 7. List SPI buses enabled: *ls -al /dev/spidev0.** > - *ISSUE1*: there is no SPI bus enabled. I need to repeat the step > 4 to finally enabled the SPI bus. So, I have added that line to > '.profile' > to have SPI enabled with every bootup. Is there any mistake at this > behaviour? > 8. Show pingroups: > - *cat /sys/kernel/debug/pinctrl/44e10800.pinmux/pingroups* > 1. group: spi0_pins_s0 > 2. pin 84 (44e10950) > 3. pin 85 (44e10954) > 4. pin 86 (44e10958) > 5. pin 87 (44e1095c) > - *QUESTION1*: How can I find out which address correspond to a > pin? I tried to find it at BBB_SRM but there is no info about. > > > Now, it is time to check SPI running a loopback example. The SPIDEV > <http://elinux.org/BeagleBone_Black_Enable_SPIDEV> guide tells to shorcut > pins 29 & 30 for SPI1, so for SPI0 pins are 18 & 21. > But, here start new problems: > > 1. Next step ask for apply *diff to the kernel*. > - *diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c* > - Output: diff: unrecognized option '--git' > - *ISSUE2*: Moreover, there is no spidev.c at BBB system. No > diff can be made. > 2. Finally, test the SPI with '*spidev_test*' program. > - *QUESTION2*: Where is that file? Or the path, > *kernel/Documentation/spi*? > > > Well, once we reach this point there is only one thing more I would like > to know. If I write a new code to work with SPI & sensors, *which > libraries should be added*? (Maybe, <*linux/spi/spidev.h*> will be > enough). > > Kind Regards. > > -- > 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 beagleboard+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- 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 beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
