CPU_BOOLEAN FSDev_BSP_SPI_Open (FS_QTY unit_nbr);
File | Called from | Code enabled by |
|---|---|---|
| Device driver | N/A |
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DEF_FAIL, otherwise.
Notes/Warnings
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- This function will be called every time the device is opened.
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- Several aspects of SPI communication may need to be configured, including:
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- Transfer unit length
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- Shift direction
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- Clock frequency
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- Clock polarity and phase (CPOL and CPHA)
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- Slave select polarity
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- For a SD/MMC card, the following settings should be used:
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- Transfer unit length: 8-bits
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- Shift direction: MSB first
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- Clock frequency: 400-kHz (initially)
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- Clock polarity and phase (CPOL and CPHA): CPOL = 0, CPHA = 0
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- Slave select polarity: active low.
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- The slave select (SSEL or CS) must be configured as a GPIO output; it should not be controlled by the CPU’s SPI peripheral. The SPI port’s
ChipSelEn()andChipSelDis()functions manually enable and disable the SSEL.