SCO OpenServer

dma_enable(D3oddi)

dma_enable -- begin DMA transfer

Synopsis

   #include <sys/dma.h>
   
   void dma_enable(unsigned chan);

Description

The dma_enable( ) function starts a DMA transfer. There is no return value. dma_enable clears the mask register on the controller to let a DMA transfer begin.

Arguments

chan

specifies the DMA channel to be used. Possible values are:

8-bit channels:: DMA_CH0, DMA_CH1, DMA_CH2, DMA_CH3
16-bit channels:: DMA_CH5, DMA_CH6, DMA_CH7

Channel 4 is not available. Other channels may be permanently allocated by system drivers. Consult the /usr/adm/messages file for which channels are in use. Use printcfg in your driver initialization routine to display the DMA channel that you select.

Return values

None.

Usage

Context and synchronization

Non-blockable, interrupt, user, or blockable context.

Hardware applicability

All.

Version applicability

oddi: 1, 2, 2mp, 3, 3mp, 4, 4mp, 5, 5mp, 6, 6mp

SVR5 DDI compatibility

This function is not supported for DDI drivers. See ``DMA'' in HDK Technical Reference for information about implementing DMA transfers in DDI drivers.

References

dma_param(D3oddi), dma_start(D3oddi), dma_relse(D3oddi), dma_alloc(D3oddi), dma_resid(D3oddi), printcfg(D3oddi)