Chapter 4
Register Descriptions
VME-MXI-2 User Manual
4-80
© National Instruments Corporation
DMA FIFO Count Register (FCRx)
FCR1 VMEbus A24 or A32 Offset: D40 (hex)
FCR2 VMEbus A24 or A32 Offset: E40 (hex)
Attributes:
Read Only
32, 16, 8-bit accessible
31
30
29
28
27
26
25
24
0
0
0
0
0
0
0
0
23
22
21
20
19
18
17
16
ECR[7]
ECR[6]
ECR[5]
ECR[4]
ECR[3]
ECR[2]
ECR[1]
ECR[0]
15
14
13
12
11
10
9
8
0
0
0
0
0
0
0
0
7
6
5
4
3
2
1
0
FCR[7]
FCR[6]
FCR[5]
FCR[4]
FCR[3]
FCR[2]
FCR[1]
FCR[0]
This register indicates the state of the DMA controller’s FIFO buffer.
Bit
Mnemonic
Description
31-24
0
Reserved
These bits are reserved. The value these bits
return when read is meaningless.
23-16
ECR[7:0]
Empty Count Register
These bits indicate the number of empty
locations (in bytes) currently in the FIFO.
15-8
0
Reserved
These bits are reserved. The value these bits
return when read is meaningless.
7-0
FCR[7:0]
Full Count Register
These bits indicate the number of bytes of data
remaining in the FIFO.
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