On Sat, Oct 19, 2013 at 7:45 PM, Richard W.M. Jones rjones@redhat.com wrote:
I'm currently testing the ODROID-XU.
i got the odroid-u2. installation report here: http://lkcl.net/reports/odroid-u2.html
yes, there is no buffer on the RS232 port. you *really* have to watch out. henrik (hno) knows the full technical details, but basically TTL "off" (0) on UART is 3.3V (opposite of what you think it might be). so when you power down, the USB-to-RS232 converter is basically providing random 3.3V power *into* the processor. This Is Generally Bad.
henrik knows how to sort this out (resistors, diode) but basically *do not* have the USB-to-RS232 converter plugged in when the power is off. if you want to get at the boot sequence, then either a) tough b) get in there quick and repeat until success! :)
i had no problems, concerns or issues about either a) the use of micro-hdmi. just get a cable. b) the sd/mmc. i got 2. 1 is an 8gb eMMC, the other was a micro-sd converter so i could plug in a standard micro-sd card. the 8gb eMMC was lightning-quick.
what did i do with it? i installed xrdp and then ran *five* simultaneous desktop sessions on it. 6 made it keel over because i hadn't set up any swap space (and you shouldn't really set up swap onto an MMC card unless you expect to replace it regularly).
so yeah basically the exynos 44xx series absolutely rocks. it's a Cortex A9 though so no virtualisation, but with xrdp being successful i genuinely didn't care. if you want a Cortex A15, go for an arndaleboard. you'll get really good performance and virtualisation.
but, price-performance wise they're all completely outclassed by an A20. don't expect speed miracles compared to an A15 or an A9, but the interfaces (SATA, Gig-Eth) and the 2gb RAM more than make up for the "lowly" dual-core A7 aspect.
btw: exynos processors have treacherous-zone capabilities and on-board secret-boot flash. unfortunately all the suppliers of exynos boards activate it, thus banning you from replacing the bootloader and often banning you from replacing u-boot as well. by contrast allwinner processors are "unbrickable". pull a pin high and you go straight into USB "loader" mode. which has been reverse-engineered and software-libre (GPLv3+) sources are available for command-line bootstrapping with a [GPL-compliant, community-managed and publicly available] modified u-boot.
l.