Metronomefb¶

Maintained by Jaya Kumar <jayakumar.lkml.gmail.com>

Last revised: Mar 10, 2008

Metronomefb is a driver for the Metronome display controller. The controlleris from E-Ink Corporation. It is intended to be used to drive the E-InkVizplex display media. E-Ink hosts some details of this controller and thedisplay media herehttp://www.e-ink.com/products/matrix/metronome.html .

Metronome is interfaced to the host CPU through the AMLCD interface. Thehost CPU generates the control information and the image in a framebufferwhich is then delivered to the AMLCD interface by a host specific method.The display and error status are each pulled through individual GPIOs.

Metronomefb is platform independent and depends on a board specific driverto do all physical IO work. Currently, an example is implemented for thePXA board used in the AM-200 EPD devkit. This example is am200epd.c

Metronomefb requires waveform information which is delivered via the AMLCDinterface to the metronome controller. The waveform information is expected tobe delivered from userspace via the firmware class interface. The waveform filecan be compressed as long as your udev or hotplug script is aware of the needto uncompress it before delivering it. metronomefb will ask for metronome.wbfwhich would typically go into /lib/firmware/metronome.wbf depending on yourudev/hotplug setup. I have only tested with a single waveform file which wasoriginally labeled 23P01201_60_WT0107_MTC. I do not know what it stands for.Caution should be exercised when manipulating the waveform as there may bea possibility that it could have some permanent effects on the display media.I neither have access to nor know exactly what the waveform does in terms ofthe physical media.

Metronomefb uses the deferred IO interface so that it can provide a memorymappable frame buffer. It has been tested with tinyx (Xfbdev). It is knownto work at this time with xeyes, xclock, xloadimage, xpdf.