peb20550 Infineon Technologies Corporation, peb20550 Datasheet - Page 242

• Manufacturer Part Number: peb20550
• Description: Extended Pcm Interface Controller
• Manufacturer: Infineon Technologies Corporation

CTAR
CBSR
CSCR
MUSAC
MOD
CFR
5.9.3.2 Space and Time Switch for 16 kbit/s Channels
The EPIC is optimized for the space and time switching of 64 kbit/s channels (8 bit time
slots). The switching of 32 and 16 kbit/s subchannels is also supported, but these
channels can only be freely selected at the PCM interface. At the CFI, only one
subchannel per 8 bit time slot can be switched (see chapter 5.4.2). Usually, this is
sufficient because on the IOM-2 interface, only one 16 kbit/s D channel per time slot
needs to be switched. Up to four D channels may then be combined into a single 8 bit
PCM time slot.
If a completely flexible space and time switch for contiguous 16 kbit/s channels is
required, the following method can be used:
The four CFI ports are connected in parallel as shown in figure 86. Each CFI port is
programmed via the CFI subchannel register (CSCR) to handle a different 2 bit subtime
slot position. With this configuration, any mixture of 16, 32 and 64 kbit/s channels may
be switched between the CFI and the PCM interfaces. Up to 128 16 kbit/s channels per
direction can be handled by the EPIC. The switching software must select the CFI port
number according to the required CFI subchannel position for each CFI - PCM
connection. The PCM subchannel position is selected via the control memory (CM) code
field (see table 24). For 32 and 64 kbit/s connections, only one CFI port of a given time
slot may be programmed in order to avoid collisions on the CFI “bus”.
Semiconductor Group
= 0000 0010
= 0010 0000
= 0000 0000
= 0100 0100
= 1111 1111
B
B
B
B
B
= 02
= 20
= 00
= 03
= DE
H
H
H
H
H
PFS marks downstream CFI TS0
PFS marks downstream CFI bit 6, upstream
bits not shifted
64, 32, 16 kbit/s channels located on CFI bits
7 … 0, 7 … 4, 7 … 6
input mode 8
4.096 MHz device clock, conferencing
mode, A-law, even bits inverted
242
4M, output mode 4
Application Hints
PEB 2055
PEF 2055
4M