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        EEPW首頁 > 手機與無線通信 > 設計應用 > 在MAX-IDE中自動初始化數(shù)據(jù)段

        在MAX-IDE中自動初始化數(shù)據(jù)段

        作者: 時間:2011-04-06 來源:網絡 收藏

        ;; This is the free-running code, executed on subsequent power-ups, that copies
        ;; values from the flash back into their proper data segment locations.

        move DP[0], #0F000h ; Source: Flash location 7000h
        move BP, #0 ; Dest: Start of RAM
        move Offs, #0
        move LC[0], #100h ; Copy 256 words
        lcall UROM_copyBuffer

        jump main

        ;; This is the first-pass code. A bit of a trick here; because enters
        ;; and exits the loader separately when loading the code and data segment files,
        ;; the application is allowed to execute briefly before the data segment file
        ;; has been loaded. The first four lines under copyFlash ensure that the
        ;; application waits for to load the data segment file before continuing.

        copyToFlash:
        move DP[0], #0h ; Wait for flag variable to be loaded by .
        move Acc, @DP[0] ; Note that this will reset the application; the
        cmp #1234h ; data segment is not loaded while the application
        jump NE, copyToFlash ; is still running.

        move DP[0], #0 ; Start of RAM variable area
        move A[4], #7000h ; Location in flash to write to
        move LC[0], #100h ; Store 256 words in flash 7000h-70FFh

        copyToFlash_loop:
        move DP[0], DP[0] ; Refresh the data pointer to read values correctly,
        ; because calling UROM_flashWrite changes memory
        ; contexts and affects the cached @DP[0] value
        move A[0], A[4] ; Location to write
        move A[1], @DP[0]++ ; Value to write (taken from RAM)
        lcall UROM_flashWrite
        move Acc, A[4]
        add #1
        move A[4], Acc
        djnz LC[0], copyToFlash_loop

        main:
        move PD0, #0FFh ; Set all port 0 pins to output
        move PO0, #000h ; Drive all port 0 pins low (LEDs off)

        move DPC, #1Ch ; Set pointers to word mode
        move DP[0], #varA
        move Acc, @DP[0]
        cmp #1234h ; Verify that the variable is set correctly
        jump NE, fail

        pass:
        move PO0, #55h
        sjump $

        fail:
        sjump $

        segment data

        org 0000h

        varA:
        dw 1234h

        org 00FFh

        varB:
        dw 5678h

        end

        結論
        MAX-IDE提供的程序段和段工具能夠在存儲器中聲明變量地址,以起始值化這些變量。可以利用應用程序在閃存中緩存這些變量,必要時恢復它們。這種方法允許基于匯編的應用程序使用MAX-IDE提供的裝載功能,無論微控制器是否連接JTAG調試器,都能保持工作。


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