On Tue, 22 Mar 2016 05:47:19 -0700 (PDT), you 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.
Had a chip (Epson S1D13781) with an SPI interface. Had a similar problem when sharing the SPI interface with another chip. Bottom line was that, unlike the standard SPI chips where the chip gets completely off line when not selected, this chip *always* (the Epson) drives MISO line low. I was getting about 1.8 volts or so maximum voltage out of the paralleled chip because it was trying to pull up a driver that was stuck at zero. Not sure that you have exactly the same problem, but is the chip you're driving somehow trying to drive this line (and shouldn't)? Harvey > >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+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
