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xro:beaglebone [2015-12-08 17:11] xro created |
xro:beaglebone [2015-12-09 00:29] xro |
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| ==== Nonstandard HMDI Resolution ==== | ==== Nonstandard HMDI Resolution ==== | ||
| + | Beaglebone X uses framebuffer device, So adding a modeline in xorg.conf won't work. | ||
| + | Likewise any fb-resolutions given on the kernelCL depend on that framebuffer-resolution already defined. | ||
| + | In the end, none of that is really needed. | ||
| + | Steps: | ||
| + | - generate a new fb config, using ''gtf <width> <height> <refreshrate> -f'' | ||
| + | - add it to ''/etc/fb.modes'' | ||
| + | - you're done, the rest happens automatically | ||
| + | |||
| + | == Example for Resolution 1440x900 == | ||
| + | |||
| + | <file txt fb.modes> | ||
| + | mode "1440x900-60" | ||
| + | # PCLK: 106.47 MHz, H: 55.92 kHz, V: 60.00 Hz | ||
| + | geometry 1440 900 1440 900 32 | ||
| + | timings 9392 232 80 28 1 152 3 | ||
| + | hsync low | ||
| + | vsync high | ||
| + | endmode | ||
| + | </file> | ||
| + | |||
| + | ==== Rotating the BeagleBone Screen / Display ==== | ||
| + | This can and should be done use X. Downside is you can't rotate the console like on the RPi. | ||
| + | Accomplish it using the ''Rotate'' X-Option of the Framebuffer Device. | ||
| + | |||
| + | <file txt xorg.conf> | ||
| + | Section "Device" | ||
| + | Identifier "Builtin Default fbdev Device 0" | ||
| + | Driver "fbdev" | ||
| + | Option "Rotate" "CCW" | ||
| + | EndSection | ||
| + | |||
| + | Section "Screen" | ||
| + | Identifier "Builtin Default fbdev Screen 0" | ||
| + | Device "Builtin Default fbdev Device 0" | ||
| + | DefaultDepth 16 | ||
| + | EndSection | ||
| + | |||
| + | Section "ServerLayout" | ||
| + | Identifier "Builtin Default Layout" | ||
| + | Screen "Builtin Default fbdev Screen 0" | ||
| + | EndSection | ||
| + | </file> | ||
| ==== Transient State of pins during startup ==== | ==== Transient State of pins during startup ==== | ||
| + | |||
| + | Basically, until the Device-Tree-Overlays are loaded, the Beageblone-Blacks gpio pins are in ''INPUT'' mode and sometimes, during bootup, may switch devices your relays and other stuff that depends on your pins being configured for ''OUTPUT'' at level 0, when powering up. | ||
| + | |||
| + | There are two possible solution that I know of. | ||
| + | - Don't power up your external gpio-controlled hardware before the BeagleBoneBlack has booted | ||
| + | - Guard your GPIO Pins with some Peripheral-Buffer IC's that need an **EN**able signal. | ||
| + | |||
| + | In both cases, you still need a pin to connect the EN signal or power-relay for our peripherals, | ||
| + | a PIN that you can trust to stay in a certain state during and after bootup. | ||
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