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Appendix C
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01270146.doc
Blue Chip Technology Ltd.
Programming Example
To set-up a DMA transfer the following program sequence is required:
Define an area of memory for the transfer
Set-up the I/O board for DMA operation
Disable the DMA channel being used.
Load the start address into PAGE register. This is the START address
register for the DMA channel being used.
Load the length count into the TRANSFER LENGTH register. Note
that the DMA controller only transfers 8 bits at a time, each value
written to an ANALOGUE OUT board or read from an ANALOGUE
IN board is 2 bytes long so the transfer length will be twice the number
of samples to be taken.
Load the mode for the selected DMA channel.
Enable the DMA channel.
The following extract from a QUICK BASIC program demonstrates how to
program the DMA controller for a WRITE transfer.
Summary of Contents for AOP-12D
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