PSB7238 SIEMENS [Siemens Semiconductor Group], PSB7238 Datasheet - Page 48

• Manufacturer Part Number: PSB7238
• Description: Joint Audio Decoder-Encoder - Multimode
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Semiconductor Group
4.2
The PSB 7238 supports a total of eight independent serial I/O-channels:
– two receive and two transmit audio channels, and
– two receive and two transmit data channels (pertaining to the two HDLC controllers).
The eight channels are transferred between the DSP and/or the parallel host interface
and one of the serial interface lines: DD or DU (IOM-2), or SR or ST (Serial Audio
Interface SAI). The capacity of each channel is individually determined by programming
the time-slot length on the selected serial interface line.
Timing Generation
The selection of the line for each of the channels is performed via SLIN1,0 (00: DU; 01:
DD; 10: SR; 11: ST). The timing logic is driven by the bit clock and frame synchronization
signals corresponding to the selected line. These are:
DCL(/2) and FSC
SCLK and RFS
SCLK and TFS
The IOM-2 timing signals can be input or output of the PSB 7238, i.e. the circuit is a slave
or master with respect to the IOM-2 interface. The selection is done by the CGEN bit in
register 202B
The timing on the SAI lines SR and ST is either input or output. In the case where the
timing is internally generated (i.e. the PSB 7238 functions as SAI master for SR and/or
ST), a schematic diagram of the generation logic is shown in Figure 19.
Audio and Data Reception/Transmission
H
.
for ST.
for DD and DU.
for SR.
48
Data Sheet 1998-07-01
Functional Blocks
PSB 7238