OK335xS 系统启动配置解析

                            OK335xS 系统启动配置解析

一、参考文档：
    AM335x ARM® Cortex™-A8 Microprocessors (MPUs) Technical Reference Manual

二、SYSBOOT Configuration Pins Notes(page ):
    . WAIT is monitored on GPMC_WAIT0.
    . MUX1 and MUX2 designate which group of XIP signals are used. Each group is defined in Table -.
    . Note that even though some bits may be a "don't care" for ROM code, all SYSBOOT values are latched into the CONTROL_STATUS register and may be used by software after ROM execution has completed.
    . SYSBOOT[:] terminals are respectively LCD_DATA[:] inputs, latched on the rising edge of PWRONRSTn.
        LCD_DATA[:]引脚电平在PWRONRSTn上升沿的时候被锁定进入SYSBOOT[:]

三、Current Configuration:
    . SYSBOOT[:]: 0b0100
    . 参考表格：Table -. SYSBOOT Configuration Pins[](page )
    . 分析配置：
        +--------+----------------+----------------+----------------+---------------+
        |  Bits  | SYSBOOT[:] | SYSBOOT[:] | SYSBOOT[:] | SYSBOOT[]    |
        +--------+----------------+----------------+----------------+---------------+
        |  value |              |              |              |              |
        +--------+----------------+----------------+----------------+---------------+
        |  mode  |  01b = 24MHz   |    reserved    |non-muxed device|ECC done by ROM|
        +--------+----------------+----------------+----------------+---------------+
        |  Bits  | SYSBOOT[]     | SYSBOOT[:]   | SYSBOOT[]     | SYSBOOT[:]  |
        +--------+----------------+----------------+----------------+---------------+
        |  value |               |              |               |               |
        +--------+----------------+----------------+----------------+               |
        |  mode  |  -bit device  |   Don't care   |CLKOUT1 disabled|               |
        +--------+----------------+----------------+----------------+               |
        |  Bits  |                 Boot Sequence                    |               |
        +--------+--------------------------------------------------+               |
        |  value |                                                             |
        +--------+------------------------------------------------------------------+
        |  mode  |                 .UART0 .XIP .MMC0 .NAND                      |
        +--------+------------------------------------------------------------------+