On Thursday, April 9, 2015 at 11:48:35 PM UTC-4, William Hermans wrote: > *The 10K pull-up didn't work. I didn't think it would, the am335x drives >> the pins low during initialization and this is overcoming the pull-up [the >> outputs were never free-floating]. I think I should have used a MAX3222 >> and wired up the SHDN pin to a GPIO so that I could independently enable >> the level converter once the system is stable (assuming I can figure out >> the .dts incantation to make a GPIO pin work under jessie/3.14-ti).* >> > > Winston is it ? >
Yes. > Anyway, you could use Charles S' universal-IO device tree overlay(s) > to do this for you. I understand that they are built into the latest > images ( for several months now ). > > https://github.com/cdsteinkuehler/beaglebone-universal-io > > I meant to demonstrate this and write up a mini how-to, but have been > really busy for the last several months . . . > I think my issue is more fundamental. The issue is really that the RS232 peripheral is connected when the BBB boots, for those first few ms, before it's even loaded u-boot, the pinmux is at it's default "zero" state and the UART pins are thus low which the peripheral reads as a stream of 0's, this continues until the dtb (I'm using jessie/3.14) is loaded that enables the UART via the pinmuxing. I had even tried building a custom version of u-boot that enabled UART5 (whereas normally it only enables UART0 for the console). Sadly, it still isn't quick enough for the peripheral not to see enough 0's to cause a serial break. Thanks! -- 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]. For more options, visit https://groups.google.com/d/optout.
