Allwinner A13 datasheet:
http://linux-sunxi.org/images/e/eb/A13_Datasheet.pdf
Boot sequence:
http://rhombus-tech.net/allwinner_a10/a10_boot_process/
Repository create by Henrik Nordstrom with many information about Allwinner processors:
https://github.com/hno/Allwinner-Info
Alan C. Assis 