Micro-SD Card Slot Abused As VGA-Port
dvdkhlng writes "The Ben NanoNote open-source hand-held computer has often been criticized for not being very extensible hardware-wise. A community effort now starts to challenge this by shipping the so-called UBB board, which plugs into the micro-SD port, making 6 I/O lines available to hardware hackers. The most impressive use so far is this VGA port implemented by just a few resistors, with signal-generation mostly controlled by software. The guy who did this calls it an 'unexpected capability.' Schematics and source code are available under the GPL."
BTW, this mailing-list post contains all the details about how the MMC (SDIO) controller is used here. An earlier version relied on doing bit-banging with the MMC lines programmed as general-purpose I/Os, but didn't even reach QVGA resolution this way.