Ambassador T8100A, T8102, and T8105
H.100/H.110 Interfaces and Time-Slot Interchangers
Advance Data Sheet
November 1999
2 Architecture and Functional Description (continued)
2.3 H-Bus Section (continued)
2.3.5 H-Bus Rate Selection and Connection Address Format (continued)
Table 44. HSH: H-Bus Stream Control, High Byte, 0x11
Reg
R/W
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
HSL
—
SGh
SGg
SGf
SGe
Symbol
Bit
7
Description
SGh
H-Bus Group H Rate Select, MSB. Programs streams 28—31.
H-Bus Group H Rate Select, LSB.
SGn = 00, 3-state
SGn = 01, 2.048 Mbits/s
SGn = 10, 4.096 Mbits/s
SGn = 11, 8.192 Mbits/s
6
SGg
SGf
5
H-Bus Group G Rate Select, MSB. Programs streams 24—27.
H-Bus Group G Rate Select, LSB.
4
3
H-Bus Group F Rate Select, MSB. Programs streams 20—23.
H-Bus Group F Rate Select, LSB.
2
SGe
1
H-Bus Group E Rate Select, MSB. Programs streams 16—19.
H-Bus Group E Rate Select, LSB.
0
A quick summary:
The CAMs and the pipeline register files operate as connection memories. The key CAM operation is based on 11
bits of stream and time slot plus 1 bit of read/write in the CAM locations compared against the state counter which
tracks the current stream and time slots (Section 2.2.5 State Counter Operation). Each H-bus CAM is looking for
matches on 16 of the 32 H-bus streams, and the local CAM is looking for a match on 16 local inputs and 16 local
outputs per time slot.
Thirteen bits are required to cover the 5120 possible time slots, but the MSB, LSB combination is used to deter-
mine which H-bus CAM is accessed: even H-bus (0, 0), odd H-bus (0, 1). The local H-bus is accessed by selecting
the upper 2 MSBs, both equal to 1. The CAM address can be thought of as following this format:
CAM Select Field Time-SlotField Stream Field
2 bits
7 bits
4 bits
This format is rate independent. The CAM select field is part of the address mode register (AMR) for CAM com-
mands (Section 2.1.3 Address Mode Register and Section 2.3.2 CAM Operation and Commands). Program-
ming examples for setting up connections can be found in Section 3.3 Basic Connections.
38
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