HFC-4S Cologne Chip AG, HFC-4S Datasheet - Page 97

• Manufacturer Part Number: HFC-4S
• Description: Isdn HDLC Fifo Controller With 8 (4) Integrated S/t Interfaces
• Manufacturer: Cologne Chip AG

Transmit operation
In transmit operation one HDLC or transparent byte is read and can be transmitted to the S/T and
the PCM interface as shown in Figure 3.3. Furthermore, data can be transmitted from the S/T in-
terface to the PCM interface. From the flow controller point of view, the switches select the source
for outgoing data.The switches are controlled by the bitmap V_DATA_FLOW[2..0] of the register
A_CON_HDLC[
Receive operation
Figure 3.4 shows the flow controller structure in receive operation. The two switches are controlled
with the bitmap V_DATA_FLOW[2..0]. FIFO data can either be received from the S/T or PCM
interface. Furthermore, data can be transmitted from the PCM interface to the S/T interface.
March 2003 (rev. A)
HFC-4S
HFC-8S
FIFO data is only transmitted to the S/T interface if V_DATA_FLOW[1] = 0.
The PCM interface can transmit a data byte which comes either from the FIFO or from the S/T
interface. Bit V_DATA_FLOW[2] selects the source for the PCM transmit slot (see Figure3.3).
The receiving S/T-channel has always the same number as the transmitting S/T-channel.
The bit V_DATA_FLOW[0] is ignored in transmit operation.
Bit V_DATA_FLOW[0] selects the source for the receive FIFO which can either be the PCM
or the S/T interface.
Furthermore, the received PCM byte can be transferred to the S/T interface. This requires bit
V_DATA_FLOW[1] = 1.
The bit V_DATA_FLOW[2] is ignored in receive FIFO operation.
channel data from
HDLC controller
HDLC controller
channel data to
Ò
,TX] where
transparent
HDLC or
data
Figure 3.3: The flow controller in transmit operation
no data
transfer
Flow Controller
in transmit operation
Ò
is a FIFO number.
Data Sheet
Data flow
transmit PCM
selection
transmit S/T
selection
0
1
0
1
V_DATA_FLOW [1]
V_DATA_FLOW [2]
switching buffer
switching buffer
switching buffer
no data
transfer
channel data from
transmit PCM slot
transmit S/T-channel
receive PCM slot
receive S/T-channel
channel data to
channel data from
channel data to
Cologne
Chip
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