Dmac Registers; Table 2-2. Dmac Command Table Format - Motorola MVME162FX Programmer's Reference Manual

Once the DMAC is enabled, the counter and control registers
should not be modified by software. When the command chaining
mode is used, the list of commands must be in local 32-bit memory
and the entries must be four-byte aligned.
A DMAC command list includes one or more DMAC command
packets. A DMAC command packet includes a control word that
defines the VMEbus AM code, the VMEbus transfer size, the
VMEbus transfer method, the DMA transfer direction, the VMEbus
and local bus address counter operation, and the local bus snoop
operation. The format of the control word is the same as the lower
16 bits of the control register. The command packet also includes a
local bus address, a VMEbus address, a byte count, and a pointer to
the next command packet in the list. The end of a command is
indicated by setting bit 0 or 1 of next command address. The
command packet format is shown in Table 2-2.
Entry
0 (bits 0-15)
1 (bits 0-31)
2 (bits 0-31)
3 (bits 0-31)
4 (bits 0-31)

DMAC Registers

This section provides addresses and bit level descriptions of the
DMAC counters, control registers, and status registers. Other
control functions are also included in this section.

Table 2-2. DMAC Command Table Format

--
Local Bus Address
Address of Next Command Packet
LCSR Programming Model
Function
Control Word
VMEbus Address
Byte Count
2
2-53