Dear Bob Feretich, In message <4d6316a8.4090...@prodigy.net> you wrote: > The BeagleBoard beagle.c file contains: > 242 /* Configure GPIOs to output */ > 243 writel(~(GPIO23 | GPIO10 | GPIO8 | GPIO2 | GPIO1), > &gpio6_base->oe); > 244 writel(~(GPIO31 | GPIO30 | GPIO29 | GPIO28 | GPIO22 | GPIO21 | > 245 GPIO15 | GPIO14 | GPIO13 | GPIO12), &gpio5_base->oe); > 246 > 247 /* Set GPIOs */ > 248 writel(GPIO23 | GPIO10 | GPIO8 | GPIO2 | GPIO1, > 249 &gpio6_base->setdataout); > 250 writel(GPIO31 | GPIO30 | GPIO29 | GPIO28 | GPIO22 | GPIO21 | > 251 GPIO15 | GPIO14 | GPIO13 | GPIO12, > &gpio5_base->setdataout); > > It first sets some pins as outputs and then initializes their values. > This can cause narrow glitches on the output pins. > > To prevent the glitches the order should be reversed. First Set the > GPIOs, then Configure them as outputs.
You are right. Can you please submit a patch? For instructions please see http://www.denx.de/wiki/U-Boot/Patches > Also, I have observed the discussion regarding moving Pin Mux control to > the kernel. This is fine except for pins that need to be configured ASAP > after power-on. (The system could sit at the u-boot command prompt > indefinitely, so the kernel pin mux configuration can be significantly > delayed.). Please leave the hook so that u-boot customizers can > configure their critical pins muxes. Which pins would that be, for example? Best regards, Wolfgang Denk -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: w...@denx.de But the only way of discovering the limits of the possible is to venture a little way past them into the impossible. - _Profiles of the Future_ (1962; rev. 1973) ``Hazards of Prophecy: The Failure of Imagination'' _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
