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23 lines
832 B
Markdown
23 lines
832 B
Markdown
Tutorial 0B - Read Sector
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=========================
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So far we have linked our data (pixmap, font) to the kernel image. It is time to read data from the
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SD card. For this tutorial we're implementing a real driver for read sector function.
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Sd.h, sd.c
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------------
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Well, it would be nice to have a mailbox for reading and writing sectors, but there isn't. So we have to
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talk directly to the EMMC, which is tricky and boring. We have to handle all kinds of cards. But finally,
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we have two function.
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`sd_init()` initialize EMMC for SD card read.
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`sd_readblock(lba,buffer,num)` read num blocks (sectors) from the SD card into buffer starting at sector lba.
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Main
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----
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We read a block after the bss segment in memory, and then we dump it to the console. The read function will
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display detailed information on the EMMC communication.
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