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回复 2# crifan
谢谢你的回复。emmc上接的nand flash的确不能当ROM用,只有价格优势了。
关于boot operation和alternative boot operation 区别如下:
the difference between boot and alternative boot operation is in the way the booting can be initialized from the
host. Once the booting is initialized, the booting process remains same in both of these operations.
Boot Operation: If the CMD line is held LOW for 74 clock cycles and more after power-up or reset operation (either through CMD0 with the argument of 0xF0F0F0F0 or assertion of hardware reset for e-MMC) before the first command is issued, the slave recognizes that boot mode is being initiated and starts preparing boot data internally.
Alternate Boot Operation: After power-up or reset operation (either assertion of CMD0 with the argument of 0xF0F0F0F0 or H/W reset if it is enabled), if the host issues CMD0 with the argument of 0xFFFFFFFA after 74 clock cycles, before
CMD1 is issued or the CMD line goes low, the slave recognizes that boot mode is being initiated and starts preparing boot data internally |
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