From: Ors T. <lis...@gm...> - 2010-09-17 12:01:41
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Hi, UART3 might be the key word here. AFAIK the OMAP boot ROM uses UART3 to boot from serial. br, Ors On Fri, Sep 17, 2010 at 7:48 AM, R. P. McMurphy <log...@gm...> wrote: > That "burst of garbage" is the OMAP internal ROM serial boot ASIC > signature. It is sent with even parity, so it will look like garbage > when receiving with no parity. It cannot be disabled, it can only be > avoided if you boot from a source that is before the serial port in > the list of boot devices, IIRC which on Gumstix is only the USB. > > On 9/17/10, Andrew Kohlsmith (mailing lists account) <ak...@mi...> > wrote: > > On Thursday, September 16, 2010 09:43:14 pm Andrew Kohlsmith (mailing > lists > > account) wrote: > >> There are two LEDs on the R2766 COM. When it's first powered on, a faint > >> green LED lights up. After a few seconds of garbage on the console > port, > >> a much brighter blue LED lights up, and the garbage continues. > > > > I think I found something. I tried a different terminal program (I > always > > use > > minicom). I downloaded and installed cutecom and something interesting > > showed > > up. > > > > When the new COM powers up, I receive a burst of garbage, the X-Loader > comes > > up, then u-boot. Cutecom displays unprintable characters as hex escape > > sequences, and this is what it printed: > > > > > -----8<---------8<------------8<---------8<------------8<---------8<------- > > \0x04\0x01\0x05\0x05\0xa3\0x06t\0xd8\0xb5b\0x81\0x01\0x00$U\0x16\0x0c > > @\0x00\0x00\0x00\0x01\0x04\0x08 @\0x00\0x00\0x00\0x00\0x01\0x04\0x08 > > @\0x00\0x00\0x00QT,0@\0x00\0x00\0x00\0x01\0x04\0x08 > > @\0x00\0x00\0x00\0x01\0x04\0x08 @\0x00\0x00\0x00\0x01\0x04\0xf8 > > > > Texas Instruments X-Loader 1.4.2 (Apr 27 2010 - 08:23:25) > > Loading u-boot.bin from nand > > > > > > U-Boot 2009.11 (Apr 27 2010 - 08:24:38) > > > -----8<---------8<------------8<---------8<------------8<---------8<------- > > > > It appears to boot normally from NAND, and I eventually get to the login > > prompt. However if I type anything at any time in the boot process > (u-boot, > > the kernel or login prompt), the COM immediately reboots, and starts ove > > again > > at the burst of garbage followed by X-loader loading U-boot. > > > > The older (R2173) COM emits something similar on startup, but keypresses > do > > not cause the COM to reboot immediately: > > > > > -----8<---------8<------------8<---------8<------------8<---------8<------- > > \0x04\0x01\0x05\0x0140\0x1d\0xbbmL\0xb0`\0x00\0x12U\0x0b\0x0c\0x10@ > \0x80\0x00\0x00\0x00\0x01\0x04\0x08 > > @\0x00\0x00\0x00\0x01\0x04\0x08 > > @\0x00\0x00\0x00QT,0@\0x00\0x00\0x00\0x01\0x04\0x08 > > @\0x00\0x00\0x00\0x01\0x04\0x08 @\0x00\0x00\0x00\0x01\0x04\0xf8 > > > > Texas Instruments X-Loader 1.4.2 (Jul 8 2009 - 21:19:00) > > Loading u-boot.bin from nand > > > > > > U-Boot 2009.06-rc2 (Jul 08 2009 - 21:20:30) > > > -----8<---------8<------------8<---------8<------------8<---------8<------- > > > > Now, I imagine that the garbage burst is some kind of header/ping for > some > > commercial development tool or something similar, but the newer burst > seems > > to > > confuse the crap out of minicom, where the older burst does not. > > > > Is there any way to disable/change this burst? I imagine it requires > > flashing a > > new X-loader into the NAND flash, something I'm not all that eager to do. > > Maybe someone knows a way to tell minicom not to freak out about it? > > > > Even with that aside, though, does anyone know why the R2766 COMs reboot > > immediately after receiving any serial input on their console port? I am > > using > > UART3 for the console, just as the Gumstix Tobi boards use, I am using > the > > same 74AHC1G126 to buffer/tristate the FT232 -> GPIO165_IR_RXD3 net as > the > > Tobi. This part of my board is identical to the Tobi (the Tobi shows the > > same > > problem with the new COM.) > > > > Since my board (and the Tobi) work fine with the older COM but not the > newer > > one, I am convinced that something subtle must have changed in the > expansion > > connector or the connection requirements between R2173 and R2766 Overo > Earth > > COMs. > > > > Does anyone have any insights to this? > > > > -A. > > > > > > > ------------------------------------------------------------------------------ > > Start uncovering the many advantages of virtual appliances > > and start using them to simplify application deployment and > > accelerate your shift to cloud computing. > > http://p.sf.net/sfu/novell-sfdev2dev > > _______________________________________________ > > gumstix-users mailing list > > gum...@li... > > https://lists.sourceforge.net/lists/listinfo/gumstix-users > > > > > ------------------------------------------------------------------------------ > Start uncovering the many advantages of virtual appliances > and start using them to simplify application deployment and > accelerate your shift to cloud computing. > http://p.sf.net/sfu/novell-sfdev2dev > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > |