Chapter 4
Register Descriptions
© National Instruments Corporation
4-55
GPIB-1014 User Manual
Sequence Control Register
VMEbus Address:
Base A 06 (hex)
Attributes:
Read/Write, Internal to DMAC
7
6
5
4
3
2
1
0
0
0
0
0
MAC
DAC
R/W
The Sequence Control Register (SCR) is used to define the sequencing of memory and device
addresses.
Bit
Mnemonic
Description
7-4r/w
0
Reserved Bits
Write zeros to these bits.
3-2r/w
MAC
Memory Address Count Bits 3 through 2
The Memory Address Count bits indicate the count sequence of the
Memory Address Register:
00 =
Memory address does not count
01 =
Memory address register counts up
10 =
Memory address register counts down
11 =
(undefined, reserved)
1-0r/w
DAC
Device Address Count Bits 1 through 0
The Device Address Count bits indicate the address sequence of the
Device Address Register. This is only used in flowthrough
memory-to-memory DMA transfers.
00 =
Device address does not count
01 =
Device address register counts up
10 =
Device address register counts down
11 =
(undefined, reserved)