am79c30a Advanced Micro Devices, am79c30a Datasheet - Page 15

• Manufacturer Part Number: am79c30a
• Description: Digital Subscriber Controller ?dsc ?circuit
• Manufacturer: Advanced Micro Devices

Line Interface Unit (LIU)
The LIU connects to the four-wire S Interface through a
pair of isolation transformers, one for the transmit and
one for the receive direction, as shown in Figure 1.
The receiver section of the LIU consists of a differential
receiver, circuitry for bit timing recovery, circuitry for de-
tecting High and Low marks, and a frame recovery cir-
cuit for frame synchronization. The receiver converts
the received pseudo-ternary coded signals to binary
before delivering them to the other blocks of the
Am79C30A/32A. It also performs collision detection (E-
and D-bit comparison) per the CCITT recommenda-
Operation
Block
DLC
DLC
DLC
DLC
DLC
DLC
DLC
DLC
DLC
DLC
DLC
DLC
DLC
PP
PP
PP
PP
PP
PP
PP
PP
PP
PP
PP
Register
D-channel Mode Register 1
D-channel Mode Register 2
—
D-channel Receive Byte Count
Register
Random Number Generator
Register
Random Number Generator
Register
First Received Byte Address
Register 4
Second Received Byte Address
Register 4
D-channel Mode Register 3
D-channel Mode Register 4
—
Address Status Register
Extended FIFO Control Register
Peripheral Port Control Register 1
Peripheral Port Status Register
Peripheral Port Interrupt Enable
Register
Monitor Transmit Data Register
Monitor Receive Data Register
C/I Transmit Data Register 0
C/I Receive Data Register 0
C/I Transmit Data Register 1
C/I Receive Data Register 1
Peripheral Port Control Register 2
Peripheral Port Control Register 3
Table 7. Indirect Register Access Guide (Continued)
Am79C30A/32A Data Sheet
Register
Number
10
11
12
13
14
15
16
17
18
10
11
6
7
8
9
1
2
3
4
5
6
7
8
9
Indirect Name
RNGR2 (MSB)
Perform 12–15
RNGR1 (LSB)
Perform 1–7
tions so several TEs can be connected to the same S
Interface.
The transmitter consists of a binary to pseudo-ternary
encoder and a differential line driver which meets the
CCITT recommendations for the S Interface.
The Am79C30A/32A can establish multiframe synchro-
nization, receive S bits, and transmit Q bits synchro-
nized to the received frame.
External Interface
The LIU can be connected to both point-to-point and
point-to-multipoint configurations at the CCITT S refer-
ence point. The point-to-point configuration consists of
one TE connected to the NT or PABX linecard. The
CIRDR0
CIRDR1
CITDR0
CITDR1
SRAR4
PPCR1
PPCR2
PPCR3
FRAR4
PPIER
MRDR
DMR1
DMR2
DRCR
DMR3
DMR4
MTDR
EFCR
PPSR
ASR
Mode Address
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
—
—
W
W
W
R
R
R
R
R
R
8AH
8BH
8CH
8DH
8EH
8FH
C0H
C1H
C2H
C3H
C3H
C4H
C4H
C5H
C5H
C8H
C9H
86H
87H
88H
89H
90H
91H
92H
One byte transferred
One byte transferred
4 bytes loaded 1–7
LSB, MSB
One byte transferred
One byte transferred
One byte transferred
One byte transferred
One byte transferred
One byte transferred
FRAR4, SRAR4, DMR3,
DMR4
One byte transferred
One byte transferred
One byte transferred
One byte transferred
One byte transferred
One byte transferred
One byte transferred
One byte transferred
One byte transferred
One byte transferred
One byte transferred
One byte transferred
One byte transferred
Byte Sequence
15