Graham is right. The oscillator used for the processor is the 24MHz crystal oscillator (Y2 in schematic), whereas, the one used by the ethernet controller or the IEP timer is 25MHz crystal oscillator (Y3 in schematic).
On Tuesday, April 25, 2017 at 5:09:50 PM UTC-7, 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/0042ccf8-a5ff-415d-80b4-557b9fdba8ad%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
