[beagleboard] Re: How to enable I2C P9_24 P926 (BBB RevC)?
Hi Robert, did you ever get this to work? If so, would you mind sharing the trick? -- 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.
[beagleboard] Re: How to enable I2C P9_24 P926 (BBB RevC)?
I've hooked up P9_24 (I2C1_SCL) to my Oscilloscope and observed the following results with i2cdetect: - When using the following command to enable all I2C ports, P9_24 remains a constant HIGH logic. i.e. no clock signal detected *# echo BB-I2C1 /sys/devices/bone_capemgr.9/slots* - When creating my own I2C device tree overlay, based on this https://github.com/beagleboard/devicetree-source/blob/master/arch/arm/boot/dts/BB-I2C1A1-00A0.dts, to enable the real I2C-1 (named I2C-2) the clock line change of logic is observable on my scope when trigerred with i2cdetect. *# i2cdetect -y -r 2* Below is a screenshot from my scope. Clearly the real I2C-1 is now enabled. https://lh5.googleusercontent.com/-tYG_HJlon8U/VDrA8pgQMcI/Bu0/pMwMJCT10KY/s1600/FTEK.JPG The only problem I now face is that i2cdetect isn't listing my StrongLink SL030 RFID device at address 0x50. It's as if the SL030 just doesn't respond... https://lh4.googleusercontent.com/-323rnZV2qfM/VDrEUdicP1I/Bu8/z46heuEJtDQ/s1600/i2cdetect-output.jpg Any advice is welcome! -- 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.
[beagleboard] Re: How to enable I2C P9_24 P926 (BBB RevC)?
Here are a few more scope output screenshots. Yellow = SDA Blue = SCL https://lh5.googleusercontent.com/-YTSCRExwI7s/VDrMNtYcCLI/BvM/EL4_Uu0-jVQ/s1600/FTEK.JPG https://lh6.googleusercontent.com/-IviT1s6jtTw/VDrMS5BQHvI/BvU/0wvUyawQbKc/s1600/F0001TEK.JPG -- 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.
[beagleboard] Re: How to enable I2C P9_24 P926 (BBB RevC)?
Here are a few more scope output screenshots. Yellow = SDA Blue = SCL *** Ignore the volts per division = 10V, I had the probe set to a x10 multiplier. *** https://lh6.googleusercontent.com/-IviT1s6jtTw/VDrMS5BQHvI/BvY/zqR2E-Y_sNA/s1600/F0001TEK.JPG https://lh5.googleusercontent.com/-YTSCRExwI7s/VDrMNtYcCLI/BvQ/Fr-klspvulk/s1600/FTEK.JPG -- 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.
[beagleboard] Re: How to enable I2C P9_24 P926 (BBB RevC)?
Here are a few more scope output screenshots of I2C-2 (really I2C-1). Yellow = SDA Blue = SCL https://lh4.googleusercontent.com/-y0dnjTDKNXU/VDrabTToykI/Bvk/bfUMroCS3vM/s1600/F0003TEK.JPG https://lh3.googleusercontent.com/-eA4TZDOw1Dw/VDrafY1LAdI/Bvs/bPoyU2Wl1e0/s1600/F0002TEK.JPG -- 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.
[beagleboard] Re: How to enable I2C P9_24 P926 (BBB RevC)?
As another means of checking that the Device Tree Overlay from this example is working, I changed the clock-frequency to 200kHz to ensure the same output can be seen on the oscilloscope. After loading the device tree overlay and running i2cdetect, I had the following output on my scope. https://lh5.googleusercontent.com/-OExs5be9KhI/VDrddvgAokI/Bv4/SovY_CPaGm8/s1600/F0004TEK.JPG Notice in the image above that my scope is now reading 147.2kHz on the clock line as opposed to the previous measurement of 86.35kHz when the clock-frequency was set to 100kHz. Why it's reading 147kHz rather than 200kHz is a mystery to me. But at least it proves it's changing as I alter reload the device tree overlay. As always, any input to this is much welcome. -- 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.
[beagleboard] Re: How to enable I2C P9_24 P926 (BBB RevC)?
As another means of checking that the Device Tree Overlay, from this source https://github.com/beagleboard/devicetree-source/blob/master/arch/arm/boot/dts/BB-I2C1A1-00A0.dts, is working, I changed the clock-frequency to 200kHz to ensure the same output can be seen on the oscilloscope. After loading the device tree overlay and running i2cdetect, I had the following output on my scope. https://lh5.googleusercontent.com/-OExs5be9KhI/VDrddvgAokI/Bv4/SovY_CPaGm8/s1600/F0004TEK.JPG Notice in the image above that my scope is now reading 147.2kHz on the clock line as opposed to the previous measurement of 86.35kHz when the clock-frequency was set to 100kHz. Why it's reading 147kHz rather than 200kHz is a mystery to me. But at least it proves it's changing as I alter reload the device tree overlay. As always, any input to this is much welcome. -- 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.
[beagleboard] Re: How to enable I2C P9_24 P926 (BBB RevC)?
I still can't get i2cdetect to recognise the SL030 on address 0x50 on I2C-2 (I2C2-1 in the documentation, P9_24 P9_26). I believe the I can enable P9_24 P9_26 with a device tree overlay correctly. When setting the Pullup or Pulldown resistors in the overlay, the changes can be seen using a multimeter on the output pins, so something is working. I will need to get my hands on an oscilloscope to check/measure if the clock data lines are working correctly. I've even tried adjusting the Clock Frequency from 100k to 400k. When the SL030 is connected to I2C-1 (really I2C-2) it does show up in i2cdetect. Though it does disappear at times. Why? I have no idea. Resetting the SL030 seems to do the trick. To enable the real I2C-1, you can either load the overlay BB-I2C1A1 in 'lib/firmware' or make your own overlay from this example https://github.com/beagleboard/devicetree-source/blob/master/arch/arm/boot/dts/BB-I2C1A1-00A0.dts Any advice is greatly welcome! -- 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.
[beagleboard] Re: How to enable I2C P9_24 P926 (BBB RevC)?
I still can't get i2cdetect to recognise the SL030 on address 0x50 on I2C-2 (I2C2-1 in the documentation, P9_24 P9_26). I believe I can enable P9_24 P9_26 with a device tree overlay correctly. When setting the Pullup or Pulldown resistors in the overlay, the changes can be seen using a multimeter on the output pins, so something is working. I will need to get my hands on an oscilloscope to check/measure if the clock data lines are working correctly. I've even tried adjusting the Clock Frequency from 100k all the way up to 400k. When the SL030 is connected to I2C-1 (really I2C-2) it does show up in i2cdetect. Though it does disappear at times. Why? I have no idea. Resetting the SL030 seems to do the trick. To enable the real I2C-1, you can either load the overlay BB-I2C1A1 in 'lib/firmware' or make your own overlay from this example https://github.com/beagleboard/devicetree-source/blob/master/arch/arm/boot/dts/BB-I2C1A1-00A0.dts Any advice is greatly welcome! -- 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.
[beagleboard] Re: How to enable I2C P9_24 P926 (BBB RevC)?
Again... to add more information on this matter, Derek Molloy has created a great video step-by-step guide about device tree overlays. Worth checking out... http://derekmolloy.ie/gpios-on-the-beaglebone-black-using-device-tree-overlays/ -- 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.
[beagleboard] Re: How to enable I2C P9_24 P926 (BBB RevC)?
Just thought I'd add an update to my findings here, if to only benefit those in the same boat as me. It looks like Device Tree Overlays are what I'm looking for. Adafruit have written a nice little guide of this here https://learn.adafruit.com/introduction-to-the-beaglebone-black-device-tree/overview . I must admit, little parts of it go over my head at the moment, but it is 1:20am after a long day at work. After a couple re-reads and trial and error, I'm sure it will sink in. There is also a nice guide to Device Tree Overlays here https://learn.adafruit.com/introduction-to-the-beaglebone-black-device-tree/overview. This link is also referenced in the Adafruit guide. Luckily for me, Adafruit discuss pins P9_24 P9_26 in their example! Although it is for enabling UART1... but close enough. -- 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.
