peb20560 Infineon Technologies Corporation, peb20560 Datasheet - Page 221

• Manufacturer Part Number: peb20560
• Description: Dsp Oriented Pbx Controller Doc
• Manufacturer: Infineon Technologies Corporation

3.1.5
The D-channel arbiter links the SACCO-A to the CFI of the EPIC-1. EPIC-1 and
SACCO-A should therefore be initialized before setting up the D-channel arbiter, as
demonstrated in chapter 3.1.6.
In downstream direction, the D-channel arbiter distributes data from the SACCO-A to the
selected subscribers. In upstream direction, the D-channel arbiter ensures that the
SACCO-A receives data from only a single correspondent at a time. Given proper
initialization, the operation of the D-channel arbiter is largely transparent. The user of the
ELIC can thus concentrate on operating the SACCO-A as described in chapters 2.1.2.5
and 3.1.4.
For the D-channel arbiter to operate as desired, the SACCO-A must be set clock mode 3
and inter frame timefill set to all ‘1’s. It is also recommended that the SACCO-A not be
set into auto-mode when communicating with downstream subscribers. The EPIC-1’s
CFI should be configured to follow the line card IOM-2 protocol, i.e.:
– CFI mode 0
– 2-Mbit/s data rate (usually with a double rate clock)
– 256 bits per frame and port (8 subscribers per port)
– 16-kbit/s D-channels positioned as bits 7,6 of time-slots (n × 4) − 1 for n = 1… 8
3.1.5.1
Sending data from the SACCO-A to downstream subscribers is handled by the transmit
channel master of the D-channel arbiter. The downstream Control Memory (CM) Code
for subscribers who may be sent data by the SACCO-A must be set to ‘1010’
even time-slot and to ‘1011’
should be programmed to “11 C/I-code 11”. For example, a CM-data entry of ‘11000011’
would set the C/I-code to ‘0000’. Refer to Figure 3-3.
If data is to be sent to a single subscriber (no broadcasting), this subscriber must be
selected in the XDC-register. Whenever the subscribers D-channel is to be output at the
ELIC’s CFI, the transmit channel master provides a 2-bit transmit strobe to the
SACCO-A. Every frame, 2 data bits are thus strobed from the SACCO-A into the
subscriber’s D-channel, when the SACCO-A has been commanded to send data. As the
subscribers D-channel recurs every 125 µs, the data is transmitted from the SACCO-A
to the subscriber at a rate of 16 kbit/s. If the SACCO-A has no data to send, it sends its
inter frame timefill (‘1’s) to the subscriber when strobed by the transmit channel master.
With the XDC.BCT bit set (broadcasting), the BCG-registers are used to select the
subscribers to whom the SACCO’s data is to be sent. The SACCO’s output is first copied
to an internal buffer. From this buffer, the data is strobed, 2 bits at a time, to all selected
subscribers. When the SACCO-A has no data to send, its inter frame timefill (‘1’s) is
copied to the buffer and strobed into the D-channels of the selected subscribers.
Semiconductor Group
D-Channel Arbiter
SACCO-A Transmission
B
for the odd time-slot. The CM-data of the even time-slot
3-15
Operational Description
PEB 20560
B
2003-08
for the