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    參數(shù)資料
    型號: PSD4135G3-B-20B81
    廠商: 意法半導體
    英文描述: Flash In-System-Programmable Peripherals for 16-Bit MCUs
    中文描述: Flash在系統(tǒng)可編程外設的16位微控制器
    文件頁數(shù): 23/93頁
    文件大小: 503K
    代理商: PSD4135G3-B-20B81
    PSD4000 Series
    Preliminary Information
    20
    9.1.1.6 Programming Flash Memory
    Flash memory must be erased prior to being programmed. The MCU may erase Flash
    memory all at once or by-sector. Flash memory sector erases to all logic ones, and its bits
    are programmed to logic zeros. Although erasing Flash memory occurs on a sector or chip
    basis, programming Flash memory occurs on a word basis.
    The PSD4000 main Flash and secondary Flash memories require the MCU to send an
    instruction to program a word or perform an erase function (see Table 8).
    Once the MCU issues a Flash memory program or erase instruction, it must check for the
    status of completion. The embedded algorithms that are invoked inside the PSD4000
    support several means to provide status to the MCU. Status may be checked using any of
    three methods: Data Polling, Data Toggle, or the Ready/Busy output pin.
    9.1.1.6.1 Data Polling
    Polling on DQ7 (DQ15) is a method of checking whether a Program or Erase instruction is
    in progress or has completed. Figure 3 shows the Data Polling algorithm.
    When the MCU issues a programming instruction, the embedded algorithm within the
    PSD4000 begins. The MCU then reads the location of the word to be programmed in Flash
    to check status. Data bit DQ7 (DQ15) of this location becomes the compliment of data bit
    7of the original data word to be programmed. The MCU continues to poll this location,
    comparing DQ7 (DQ15) and monitoring the Error bit on DQ5 (DQ13). When the DQ7
    (DQ15) matches data bit 7 of the original data, and the Error bit at DQ5 (DQ13) remains
    ‘0’, then the embedded algorithm is complete. If the Error bit at DQ5 is ‘1’, the MCU should
    test DQ7 (DQ15) again since DQ7 (DQ15) may have changed simultaneously with DQ5
    (DQ13) (see Figure 3).
    The Error bit at DQ5 (DQ13) will be set if either an internal timeout occurred while the
    embedded algorithm attempted to program the location or if the MCU attempted to
    program a ‘1’ to a bit that was not erased (not erased is logic ‘0’).
    It is suggested (as with all Flash memories) to read the location again after the embedded
    programming algorithm has completed to compare the word that was written to Flash with
    the word that was intended to be written.
    When using the Data Polling method after an erase instruction, Figure 3 still applies.
    However, DQ7 (DQ15) will be ‘0’ until the erase operation is complete. A ‘1’ on DQ5
    (DQ13) will indicate a timeout failure of the erase operation, a ‘0’ indicates no error.
    The MCU can read any location within the sector being erased to get DQ7 (DQ15) and
    DQ5 (DQ13) .
    PSDsoft generates ANSI C code functions which implement these Data Polling
    algorithms.
    The
    PSD4000
    Functional
    Blocks
    (cont.)
    相關(guān)PDF資料
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    PSD4135G3-B-20B81I Flash In-System-Programmable Peripherals for 16-Bit MCUs
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    PSD4135G3-B-20JI Flash In-System-Programmable Peripherals for 16-Bit MCUs
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    相關(guān)代理商/技術(shù)參數(shù)
    參數(shù)描述
    PSD4135G3-B-20B81I 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Flash In-System-Programmable Peripherals for 16-Bit MCUs
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    PSD4135G3-B-20JI 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Flash In-System-Programmable Peripherals for 16-Bit MCUs
    PSD4135G3-B-20M 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:Flash In-System-Programmable Peripherals for 16-Bit MCUs
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