Robostix framebuffer

From GumstixDocsWiki

Jump to: navigation, search

By default, the newer buildroots enable frame buffer support. Since the robostix uses some of the LCD data lines to control voltage regulators and voltage converters, when the frame buffer is enabled it can cause some mysterious behaviours.

The most obvious mysterious behaviour is random garbage characters received on the console. This is caused because the voltage converter responsible for converting the 5v version of FFUART to the 3.3v version used by the gumstix.

To get around this problem, you have a couple of options:

If you haven't built buildroot yet

You can edit the gumstix-buildroot/target/device/Gumstix/verdex/linux.config (for the verdex) or gumstix-buildroot/target/device/Gumstix/basix-connex/linux.config (for the basix or connex) and change 

CONFIG_FB=y

to 

# CONFIG_FB is not set

If you've already built buildroot

cd gumstix-buildroot/build_arm_nofpu/linux-2.6.21gum
make ARCH=arm menuconfig
Under Device Drivers-->
  Graphics support -->
    Unselect "Support for framebuffer devices"
Exit saving your changes.
rm arch/arm/boot/compressed/vmlinux
cd ../..
make

If you've already downloaded the errant kernel, you only need to update the kernel (uImage) and not the rootfs. I find using the loady command (in u-boot) and sending the uImage file over serial via Y-Modem to fairly quick for uploading just the kernel.

Retrieved from "http://docwiki.gumstix.org/index.php/Robostix_framebuffer"
Personal tools