On Mon, 6 Jan 2020 16:46:04 -0800 (PST), in gmane.comp.hardware.beagleboard.user [email protected] wrote:
> >Oh wow, I guess this is close to what I was looking for: >https://elinux.org/BeagleBone_VGA > >I can't tell if it's a dead project ("Discontinued") or a work in progress >("Manufacturer's link available soon") > >Also, it sounds like it still uses a lot of pins.. probably because it's >supporting full VGA including VGA graphics modes. If it acted as a real VGA board (with VGA rendering circuits and memory) it would probably take a LOT more pins. Real VGA boards were memory-mapped into the processor space (for that era, that means it likely had 16 address lines) along with 8 data lines. Since the Beagle does not expose the processor address lines (except possibly for RAM, if the RAM is not inherent to the SoC itself) that means using GPIO to emulate a parallel address bus, along with GPIO for the 8-bit data bus... OR one uses a serial transfer to send address and data information -- in which case one is talking I2C or SPI (or pure UART), and one is giving up the speed advantage of parallel I/O ports&addressing. There is a lack of information for that cape -- but I'm willing to lay odds at 90% that the cape does NO VGA rendering. I suspect it was simply an LCD <> VGA converter, using a number of gates to combine digital LCD color information into VGA analog RGB. It most likely requires the native LCD/HDMI framer to do actual rendering of the image, with the LCD driver configured for horizontal/vertical sync at VGA speed. -- Dennis L Bieber -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/c0j91f5m6s23740kja7uvpbiloegviq718%404ax.com.
