That brings tears to my eyes seeing someone quoting the manual. Yes, don't screw up the SYS_BOOT pins.
Gerald On Wed, Jan 4, 2017 at 5:12 PM, Justin Pearson <justin.pear...@gmail.com> wrote: > Expanding Chad's comment, in the Beaglebone Black System Reference Manual > (Rev B, Jan 20, 2014) > > https://github.com/CircuitCo/BeagleBone-Black/blob/ > 390c46a03e039661aeca6eab22e6c383d8d537f8/BBB_SRM.pdf > > "Figure 39. Processor Boot Configuration" in "Section 6.8 Default Boot > Options" says that the top two bits of the SYSBOOT register, > SYSBOOT[15:14], seem to select which oscillator is used (19.2MHz, 24MHz, > 25MHz, 26MHz). > > "Figure 38. Processor Boot Configuration Design" shows that SYS_BOOT14 and > 15 are physically lcd_data14 and 15. > > "Table 12. Expansion Header P8 Pinout" shows that lcd_data14 and 15 are > GPIO0[10] and GPIO0[11] in MODE0. > > Section "8.1.1 LCD Pins" contains the warning: > > "These pins are also the SYSBOOT pins. DO NOT drive them before the > SYS_RESETN signal goes high. If you do, the board may not boot because you > would be changing the boot order of the processor." > > In Fig 39, I see that SYSBOOT[15:14] == 01b results in 24 MHz, whereas 11b > results in 26MHz, whose 8% difference may account for your ~5 sec offset > per minute. (If 24MHz is the default, I'm not sure.) > > Best, > Justin > > > > On Wednesday, January 4, 2017 at 5:12:24 AM UTC-8, cmbaker3 wrote: >> >> Johan, >> That pin is used during the boot operation. >> Check in the SRM for the default boot options. >> >> On 1/4/2017 5:39 AM, Johan Ribenfors wrote: >> >> We've recently found a strange problem. Repeatable across all eleven >> boards we've tried so far. >> >> When pin 32 on P8 (gpoi0[11]) is pulled high via a resistor on boot, the >> clock on the BBB runs ~7000 seconds slow a day. (~5 seconds a minute) >> >> If the pin is pulled low or left floating on boot, the clock keeps time. >> >> The device tree overlay was set to 0x37 for this pin - fast slew, output, >> pullup, mode 7, but changing this has no effect. >> >> We were using Debian 7.9 with various programs installed, a few device >> tree overlays applied and a custom cape when we noticed this, but it's >> still the case using the Debian 8.6 image with no modifications, no dto and >> no cape. >> >> We haven't been able to find anything online and don't really know where >> to start looking. >> >> Any ideas? >> -- >> 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. >> To view this discussion on the web visit https://groups.google.com/d/ms >> gid/beagleboard/e0647cb0-ac27-44ed-a11b-a6f71b7ef077%40googlegroups.com >> <https://groups.google.com/d/msgid/beagleboard/e0647cb0-ac27-44ed-a11b-a6f71b7ef077%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> >> >> >> -- >> Chad Baker Memphis, TN >> > -- > 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. > To view this discussion on the web visit https://groups.google.com/d/ > msgid/beagleboard/79bac7d6-3011-44b5-95ac-61c43cb8525c%40googlegroups.com > <https://groups.google.com/d/msgid/beagleboard/79bac7d6-3011-44b5-95ac-61c43cb8525c%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- Gerald ger...@beagleboard.org http://beagleboard.org/ gcol...@emprodesign.com -- 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. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAHK_S%2Bc0%3DS__LXv5wbF_%2B9xP9chLWxErTbCvcxOyejQv8pASZw%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
