Trait Source

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pub trait Source: Sealed {
    type Error;

    // Required methods
    fn is_valid(&self) -> bool;
    fn is_empty(&self) -> bool;
    fn increment(&self) -> SRCINC_A;
    fn transfer_count(&self) -> Option<u16>;
    fn end_addr(&self) -> *const u8;
    fn finish(&mut self) -> Result<(), Self::Error>;
}

Expand description

The source of a DMA transfer

This trait’s methods are intended for internal use only. It is implemented for immutable static buffers and peripherals that support being read from using DMA.

Required Associated Types§

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type Error

The error that can occur while finishing the transfer

Required Methods§

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fn is_valid(&self) -> bool

Indicates whether the source is valid

Buffers are valid, if they have a length of 1024 or less. Peripherals are always valid.

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fn is_empty(&self) -> bool

Indicates whether the source is empty

Buffers are empty, if they have a length of 0. Peripherals are never empty.

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fn increment(&self) -> SRCINC_A

The address increment during the transfer

Buffers will return the word size here. Peripherals will indicate no increment.

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fn transfer_count(&self) -> Option<u16>

The transfer count, as defined by XFERCFG.XFERCOUNT

Only buffers will return a value here, and only if is_empty returns false. Peripherals will always return None.

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fn end_addr(&self) -> *const u8

The end address

This is not the actual end of the buffer, but the starting address plus transfer_count times address increment. See LPC845 user manual, section 16.5.2, for example.

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