PSB7238 SIEMENS [Siemens Semiconductor Group], PSB7238 Datasheet - Page 176

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

Semiconductor Group
The SR request will be recognized by the JADE, but not immediately be serviced. It is
stored in an internal interrupt buffer and the VocFin is handled first as the higher priority
interrupt. So, the host must not wait for the SR request to be serviced, but has to be able
to recognize a VocFin interrupt from the JADE after an SR request. The VocFin interrupt
then is serviced as usual and only after the corresponding handshake mechanism is
finished, the SR request is serviced by the JADE.
6.2.3.3
This is the default mode of the JADE (ISEL(1-0) = 10). The complete setup of the
interfaces, time slots and so on is done by the on-chip firmware after reset, so that a
standalone application with a video processor using the IOM-SAI interface combination
can be realized without the need of an additional host.
Figure 53
The on-chip firmware uses the HDLC1 controller in transparent mode for the transfer of
the compressed audio data over the serial audio interface. During the initialization phase
after a reset, the internal firmware programs the configuration/control registers (see
Section 5.3) and the HDLC1 controller (see Section 5.4). This results in a serial clock
rate of 1.23 MHz continously generated by the JADE, a 16-bit time-slot length and MSB
sent/received first. The frame sync signals RFS and TFS are generated by the JADE
non-continously, i.e. during one frame only the exact number of frame syncs needed for
the transfer of the current packet of data is generated in one burst.
The IOM interface is in TE mode (double DCL clock) and IC1/2 channels are selected
for the 16-bit linear data transfer between the JADE and the analog front end (AFE). The
DD line is output of the JADE, DU is input to the JADE.
This configuration may be changed by the host by just overwriting the corresponding
registers.
Uncompressed Data: IOM IF, Compressed Data: Serial Audio
Interface (SAI)
176
Data Sheet 1998-07-01
Firmware Features
PSB 7238