从休眠模式(Poweroff)唤醒过程

1.一旦某个唤醒源有信号进来，内部的复位信号will be asserted；This reset duration由内部的16-bit 计数器逻辑决定，the reset assertion time由tRST = (65535 /XTAL_frequency)计算得来。

问题：reset duration和the reset assertion time表示什么？？有什么区别？？

2.检查GSTATUS2[2],看上电是否是由休眠模式唤醒而引起的；

    ldr    r1, =GSTATUS2           ; Determine Booting Mode
    ldr    r10, [r1]
    tst    r10, #0x2
    beq    %F2                     ; if not wakeup from PowerOffmode Skip
                                ;    MISCCR setting

三种复位模式：Power on reset，Power_OFF reset，Watchdog reset.对应于GSTATUS2[0~2]

3，通过设置MISCCR[19:17]位为000b来释放SDRAM信号保护

    ldr     r1, =MISCCR         ; MISCCR's Bit 17, 18, 19 -> 0
    ldr    r0, [r1]                ; I don't know why, Just fallow Sample Code.
    bic    r0, r0, #(7 << 17)      ; SCLK0:0->SCLK, SCLK1:0->SCLK, SCKE:L->H
    str    r0, [r1]

4，配置SDRAM内存控制器

    ; Set memory control registers
    add        r0, pc, #SMRDATA - (. + 8)
    ldr    r1, =BWSCON    ; BWSCON Address
    add    r2, r0, #52    ; End address of SMRDATA
loop10
    ldr    r3, [r0], #4
    str r3, [r1], #4
    cmp    r2, r0
    bne loop10

S3c2410共有13个存储控制寄存器，每个寄存器占4个字节，共52个字节

5，等待SDRAM的自刷新被释放

    mov r1, #256
loop11
    subs r1, r1, #1        ; wait until the SelfRefresh is released.
    bne loop11

6，用户可以根据自己的目的来使用GSTATUS3,4，因为在休眠模式GSTATUS3,4中的值被保留

7. – For EINT[3:0], check the SRCPND register.
    – For EINT[15:4], check the EINTPEND instead of SRCPND (SRCPND will not be set although some bits of
EINTPEND are set.).
    – For alarm wake-up, check the RTC time because the RTC bit of SRCPND isn’t set at the alarm wake-up.
    – If there was the nBATT_FLT assertion during POWER_OFF mode, the corresponding bit of SRCPND has
been set.