PSB7238 SIEMENS [Siemens Semiconductor Group], PSB7238 Datasheet - Page 33

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

PSB 7238
Interfaces and Memory Organization
Alignment of Data for Audio Channels
The most significant bit is always the first bit received/transmitted. Therefore, if audio is
processed in units of N bits (N programmable between 1 and 32), the alignment of the
data for receive and transmit audio channels in the registers is as shown in the
Figure 12.
Figure 12
Alignment of Data for HDLC/Transparent Serial Data Receiver and Transmitter
Registers
In the HDLC controllers the reception/transmission of most significant or least significant
bit can be selected by control switches (RMSB, XMSB). Nevertheless, for serial data
communication, the convention is that the least significant bit of user data is
received/transmitted first. In order to have an identical format for the data in the serial
controller input/output registers as in the FIFOs, the data is aligned in the registers as
shown below (the available options for data unit sizes when pre/postprocessing
HDLC/transparent data are: 1, 2 or 4 bytes).
Figure 13
Semiconductor Group
33
Data Sheet 1998-07-01