Thanks for responding Gerald. The scope capture above was done with no cape. It was taken from SPI0. The chip has one-way communication so I'm only using SPID1 (P9_18 from memory). The clock is coming from P9_22. Chip select is P9_17. When I get home tonight I'll try the same from SPI1 and see if it's affected as well.
On Tuesday, March 22, 2016 at 9:39:30 AM UTC-4, Gerald wrote: > > No way for me to tell what you may have done, but 1.8V is not good. Any > chance you can provide more information like the pin number and connector > you are using? > What do you have connected to this pin? > How is that device powered? > > Gerald > > > On Tue, Mar 22, 2016 at 6:47 AM, Walker Archer <warch...@gmail.com > <javascript:>> wrote: > >> I've been building a custom cape for a robotics project and one of the >> chips I'm using is controlled via SPI. I've used an oscilloscope to >> validate that the SPI is working as expected. However, two days ago I >> noticed that the chip stopped responding and after scoping the SPI signal I >> can see that the BBB is sending the SPI data pulses at 1.8v. The SPI >> signal is still happening... and the clock signal is still at 3.3v. It's >> just the SPI data line that is only peaking at 1.8v. >> >> So, I'm wondering if I've done something bad to my BBB or if I've somehow >> triggered a feature that I don't know about yet. I'm attaching a photo of >> the oscilloscope screen that shows the issue. >> >> -- >> 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...@googlegroups.com <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > > > > -- > Gerald > > ger...@beagleboard.org <javascript:> > http://beagleboard.org/ > gco...@emprodesign.com <javascript:> > > -- 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.
