• Planning things out

    David Kuder01/23/2018 at 06:00 0 comments

    First thing will be to port RaSCSI to the BeagleBoneBlack & PocketBeagle.  This provides a fallback mode in case I suck at implementing the SELECT task in the PRU.  Due to the lack of pinmux control from the PRU side, implementing the full PHY in the PRUs would be very difficult on the PocketBeagle.  Instead I intend to use PRU0 to look for our configured SCSI IDs, signal BSY to the host and trigger an interrupt on the AM3358 which will take over the SCSI pins.  The host will signal the PRU once it has passed back control.  This will reduce the cpu load outside of active transfers (no need to poll the bus state while in SELECT) and give Linux a chance to buffer data and handle other tasks when realtime execution isn't necessary.