28478G-18 Mindspeed Technologies, 28478G-18 Datasheet - Page 102

• Manufacturer Part Number: 28478G-18
• Description: Multichannel Synchronous Communications Controller 208-Pin BGA
• Manufacturer: Mindspeed Technologies

Specifications of 28478G-18

• Package: 208BGA
• Maximum Data Rate: 32768 Kbps
• Transmission Media Type: Wire
• Power Supply Type: Analog
• Typical Supply Current: 250 mA
• Typical Operating Supply Voltage: 3.3 V
• Minimum Operating Supply Voltage: 3 V
• Maximum Operating Supply Voltage: 3.6 V

Table 5-15.
5.2.2.8
To provide the subchanneling feature, MUSYCC shares the time slot mapping function between a Time Slot Map
and a Subchannel Map. The transmit and receive functions each have a separate pair of maps.
The Time Slot Map indicates if the time slot is enabled and configured for subchanneling. The TSEN bit field in the
Time Slot Descriptor specifies the mode of operation for the time slot. If TSEN = 6, the time slot is in subchannel
mode with bit 0 disabled. If TSEN = 7, the time slot is in subchannel mode with bit 0 enabled and mapped to the
channel specified in the CH bit field in the same Time Slot Descriptor. The CHx bit field is also used in the
treatment of the remaining 7 bits in the time slot, specifically as part of an index into Subchannel Map. The Time
Slot Map always manages (disables or enables or maps) bit 0 of the time slot. The Subchannel Map configures
each of the remaining 7 bits of a time slot.
The CHx bit field (0–31) from the Time Slot Descriptor is linked with the bit number (1–7) of the time slot being
processed to form an 8-bit index (0–255) into the Subchannel Map for each bit number. The Subchannel Map
associates each bit of a time slot to a channel.
For a time slot configured for subchannel mode, MUSYCC considers each bit of that time slot independently of any
other bit in the same time slot. Any bit can be enabled or disabled. The time slot is considered to consist of 8
individual 8 kbps bit streams, or subchannels. The subchannels can remain separated or be concatenated to
provide one or more subchannels running at bit rates between 8 kbps and 64 kbps, inclusive, in multiple of 8 kbps.
Note the following special cases for subchannel map assignments:
•
•
•
28478-DSH-002-E
Field
15:13
12:8
Bit
7:5
4:0
Bit 0 is always disabled or enabled/mapped by the Time Slot Map; therefore, configuring the Subchannel Map
for bit 0 is not required.
Assigning the same channel number for all bits (including bit 0) is equivalent to disabling the subchanneling
feature and treating the time slot as if in 64 kbps mode.
Disabling all bits in subchannel mode is equivalent to disabling the time slot using the Time Slot Map.
TSEN1[2:0]
TSEN0[2:0]
CH1[4:0]
CH0[4:0]
Time Slot Descriptor (2 of 2)
Name
Subchannel Map
Preliminary Information / Mindspeed Proprietary and Confidential
Value
0–31
0–31
1–3
1–3
0
4
5
6
7
0
4
5
6
7
Time Slot Disabled. Default.
Reserved.
Time Slot Enabled. 64 kbps mode.
Time Slot Enabled. 56 kbps mode.
Time Slot Enabled. Subchannel mode w/o first bit.
Time Slot Enabled. Subchannel mode w/ first bit.
Channel number assigned to this time slot.
Time Slot Disabled. Default.
Reserved.
Time Slot Enabled. 64 kbps mode.
Time Slot Enabled. 56 kbps mode.
Time Slot Enabled. Subchannel mode w/o first bit.
Time Slot Enabled. Subchannel mode w/ first bit.
Channel number assigned to this time slot.
Mindspeed Technologies
®
Description
Memory Organization
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