
DS31256 256-Channel, High-Throughput HDLC Controller
2 of 183
TABLE OF CONTENTS
1. MAIN FEATUERS............................................................................................................................. 6
2. DETAILED DESCRIPTION............................................................................................................. 7
3. SIGNAL DESCRIPTION................................................................................................................. 13
3.1 O
VERVIEW
/S
IGNAL
L
IST
..............................................................................................................................13
3.2 S
ERIAL
P
ORT
I
NTERFACE
S
IGNAL
D
ESCRIPTION
.........................................................................................18
3.3 L
OCAL
B
US
S
IGNAL
D
ESCRIPTION
..............................................................................................................19
3.4 JTAG
S
IGNAL
D
ESCRIPTION
........................................................................................................................22
3.5 PCI B
US
S
IGNAL
D
ESCRIPTION
...................................................................................................................22
3.6 PCI E
XTENSION
S
IGNALS
............................................................................................................................25
3.7 S
UPPLY AND
T
EST
S
IGNAL
D
ESCRIPTION
....................................................................................................25
4. MEMORY MAP ............................................................................................................................... 26
4.1 I
NTRODUCTION
............................................................................................................................................26
4.2 G
ENERAL
C
ONFIGURATION
R
EGISTERS
(0
XX
)............................................................................................26
4.3 R
ECEIVE
P
ORT
R
EGISTERS
(1
XX
) ................................................................................................................27
4.4 T
RANSMIT
P
ORT
R
EGISTERS
(2
XX
)..............................................................................................................27
4.5 C
HANNELIZED
P
ORT
R
EGISTERS
(3
XX
).......................................................................................................28
4.6 HDLC R
EGISTERS
(4
XX
).............................................................................................................................29
4.7 BERT R
EGISTERS
(5
XX
)..............................................................................................................................29
4.8 R
ECEIVE
DMA R
EGISTERS
(7
XX
)................................................................................................................29
4.9 T
RANSMIT
DMA R
EGISTERS
(8
XX
).............................................................................................................30
4.10
FIFO R
EGISTERS
(9
XX
)...........................................................................................................................30
4.11
PCI C
ONFIGURATION
R
EGISTERS FOR
F
UNCTION
0 (PIDSEL/A
XX
)......................................................31
4.12
PCI C
ONFIGURATION
R
EGISTERS FOR
F
UNCTION
1 (PIDSEL/B
XX
)......................................................31
5. GENERAL DEVICE CONFIGURATION AND STATUS/INTERRUPT.................................. 32
5.1 M
ASTER
R
ESET AND
ID R
EGISTER
D
ESCRIPTION
.......................................................................................32
5.2 M
ASTER
C
ONFIGURATION
R
EGISTER
D
ESCRIPTION
....................................................................................32
5.3 S
TATUS AND
I
NTERRUPT
.............................................................................................................................34
5.3.1
General Description of Operation......................................................................................................34
5.3.2
Status and Interrupt Register Description..........................................................................................37
5.4 T
EST
R
EGISTER
D
ESCRIPTION
.....................................................................................................................43
6. LAYER 1............................................................................................................................................ 44
6.1 G
ENERAL
D
ESCRIPTION
...............................................................................................................................44
6.2 P
ORT
R
EGISTER
D
ESCRIPTIONS
...................................................................................................................48
6.3 L
AYER
1 C
ONFIGURATION
R
EGISTER
D
ESCRIPTION
...................................................................................51
6.4 R
ECEIVE
V.54 D
ETECTOR
............................................................................................................................56
6.5 BERT...........................................................................................................................................................60
6.6 BERT R
EGISTER
D
ESCRIPTION
...................................................................................................................61
7. HDLC................................................................................................................................................. 67
7.1 G
ENERAL
D
ESCRIPTION
...............................................................................................................................67
7.2 HDLC R
EGISTER
D
ESCRIPTION
...................................................................................................................69
8. FIFO................................................................................................................................................... 74
8.1 G
ENERAL
D
ESCRIPTION AND
E
XAMPLE
......................................................................................................74
8.1.1
Receive High Watermark....................................................................................................................76
8.1.2
Transmit Low Watermark...................................................................................................................76
8.2 FIFO R
EGISTER
D
ESCRIPTION
.....................................................................................................................76
9. DMA................................................................................................................................................... 83
9.1 I
NTRODUCTION
............................................................................................................................................83
9.2 R
ECEIVE
S
IDE
..............................................................................................................................................85
9.2.1
Overview.............................................................................................................................................85
9.2.2
Packet Descriptors..............................................................................................................................90
9.2.3
Free Queue .........................................................................................................................................92