SVR5 and SCO OpenServer 5

RelReqDMA(D4pccard)

RelReqDMA -- describe DMA channel assigned to the PC Card configuration

Syntax

   #include <sys/lcs.h>
   #include <sys/lss.h>

Description

The RelReqDMA structure is used to release or request a DMA channel for the configuration of a PC Card in the specified socket.

Structure definition

   unsigned short  	usSocket;
   unsigned short  	usDesiredChannel;
   unsigned short  	usAttributes;
   unsigned char   	ucAssignedChannel;

Structure members

The members are defined as:

usSocket

Logical socket.

usDesiredChannel

Bit-mapped field indicating DMA channel. Bits D0-D15 correspond to DMA channels 0-15. If bit is set to 1, the channel is acceptable to the requesting client. A client can accept any channel if all bits are set to 1.

usAttributes

Bit-mapped field indicating signal to use for DMA request and DMA width.

bits 0-1

Shared mode. Binary value identifying how DMA channel is shared:

1: exclusive (not shared)
1: time-multiplexed shared
2: dynamically shared
3: reserved

bits 2-3

DMA request signal. binary value that identifies the pin on the interface used to signal a DMA request.

0: reserved (do not use)
1: DREQ# uses SPKR#
2: DREQ# uses IOIS16#
3: DREQ# uses INPACK#

bit 4

desired width of a DMA data transfer

0: 8 bits
1: 16 bits

bits 5-7

resesrved (reset to zero)

ucAssignedChannel

Binary value indicating assigned DMA channel.

Usage

Hardware applicability

All

Version applicability

pccard: 1, 2, 3

References

ReleaseDMA(D3pccard), RequestDMA(D3pccard)