The CPU in a BBB runs from a 24 MHz Oscillator. There is a 25 MHz oscillator on the board, but that is for the Ethernet. --- Graham
== On Tuesday, April 25, 2017 at 7:09:50 PM UTC-5, Justin Pearson wrote: > > How can I find out whether the PRU and CPU are driven by the same > oscillator? Specifically, a colleague told me that the IEP timer (which I'm > reading with the PRU) is driven by a 24 MHz oscillator that's PLL'd so the > timer increments at 200 MHz, whereas the CPU is driven by a 25 MHz > oscillator PLL'd so that the CPU runs at 1 GHz. > > It seems to me that if they're driven by different oscillators, then they > could drift apart over time. > > Page 1177 of the TRM (spruh73n.pdf) mentions a 32-kHz crystal oscillator, > but I don't see how that's related. > > Also, are these oscillators within the Sitara SoC, or somewhere else on > the BBB? The SRM just references 24.576 MHz oscillator (pg 70 of e14 > BBB_SRM_rev 0.9.pdf), and I'm not sure how that's related to the 24/25 MHz > oscillators my colleague mentioned. > > Thanks for your help. > > -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/e8696c15-38e4-4077-aa0f-658c28868762%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
