User`s manual

DMA - Block of Memory Move
3-41
3
Options
Description
The DMA command moves blocks of data from the local bus to the
VMEbus, or from the VMEbus to the local bus. This command.
utilizes the hardware capability of Direct Memory Access (DMA).
Refer to the board installation and use manual for a detailed
description of DMA. You can not perform a DMA from the local
bus to the local bus, or from the VMEbus to the VMEbus.
The DMA command copies (DMAs) the contents of the memory
addresses defined by RANGE to another place in memory,
beginning at ADDR.
The option field is only allowed when RANGE is specified using a
COUNT. In this case, the
B, H, or W defines the size of the data to
which the COUNT is referring. For example, a COUNT of four with
an option of
W means to move four words (or 16 bytes) to the new
location. If an option field is specified without a COUNT in the
RANGE, an error results. The default data type is word.
Refer to the VMEbus specification for the complete description of
block transfer mode. The VMEbus transfer address must also
support block transfers if enabled, refer to the applicable board
installation and use manuals.
At the end of the transfer, the DMA command displays the
completion status of the transfer. A completion status of $1 is a
successful transfer. Any other completion status means that the
transfer was not successful. This status comes directly from the
hardware status from the DMA controller.
B Byte
H Half-word
W Word