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DMAioe2mem

int DMAioe2mem( dma_chan_t handle, dma_addr_t dest, unsigned int src, unsigned int len, unsigned int flags );

Description

This function performs an immediate DMA operation from external I/O to memory.

Parameters

handle

Handle for channel to use in transfer

dest

Memory destination address

src

External I/O location source address

len

Length to send (cannot equal zero)

flags

Various flag options.

• DMA_F_REPEAT indicates that the transfer will be a cycle

• DMA_F_INTERRUPT indicates an interrupt will be triggered at the completion of the transfer. The interrupt vector and function must be set up in the user's code.

• DMA_F_LAST_SPECIAL (only for Ethernet or HDLC peripherals)
  Internal Source: Status byte written to initial buffer descriptor before last data.
  Internal Destination: Last byte written to offset address for frame termination.
  All Others: no effect.

• DMA_F_SRC_DEC only for transfers with memory source. Indicates the source address should be decremented.

• DMA_F_DEST_DEC only for transfers with memory destination. Indicates the destination address should be incremented.

• DMA_F_STOP_MATCH indicates whether or not to stop the dma transfer when a character is reached. The match byte and mask should have previously been set by calling the DMAmatchSetup() function.

• DMA_F_TIMER indicates the DMA timer will be used. The divisor should have already been set by calling the DMAtimerSetup() function.

• DMA_F_TIMER_1BPR indicates that the timed transfers will send one byte per request instead of the entire descriptor

Only one of the following flags (if any) should be set. They indicate that the DMA transfer is gated using the named pin:

• DMA_F_PD2, DMA_F_PE2, DMA_F_PE6, DMA_F_PD3, DMA_F_PE3, DMA_F_PE7

The following flags indicate the polarity of the gating signal:

• DMA_F_FALLING (default), DMA_F_RISING, DMA_F_LOW, DMA_F_HIGH

Return Value

0: Success
-EINVAL: Invalid handle
-EBUSY: Resources are busy

Library

DMA.LIB

See Also

DMAmem2mem, DMAcompleted, DMAstop