
PSB 7230
Firmware Features
Semiconductor Group
145
Data Sheet 1998-07-01
6.2.3
In this chapter the timings and/or interrupt handshake procedures are described for the
different hardware interface selections (Host/Host, IOM/Host, IOM/Serial Audio
Interface).
After a hardware reset the firmware automatically does all necessary initializations for
the IOM/Serial Audio Interface combination described in
Chapter 6.2.3.3
. The other
interface combinations can be configured by configuring the control block (see
Chapter 6.2.1.1
).
Note: After a hardware reset, the JADE AN firmware needs to initialize its internal
memories and interfaces. The time to do this is less than 10 ms. The user must
take care to access the JADE AN only after this initialization phase is completed,
i.e. 10 ms after the hardware reset.
Audio Interface Timings
6.2.3.1
This interface combination is used for offline processing of audio (ISEL(1-0) = 00). I.e.
the compression can be done faster than realtime, because the JADE AN is in each
mode able to process audio at least in realtime. This definitely also depends on the
capabilities of the host processor to provide a fast interrupt service to the handshake
procedure described below. The most complex algorithm is G.723, in this mode the
maximum possible speed is only slightly faster than realtime, because almost all of the
computational power of the JADE AN is needed to compress the audio. The 8 kHz
pass-through mode is not available with this interface combination.
The basic structure of data exchange between the Host and the JADE AN is shown in
the
Figure 46
.
Uncompressed Data: Host IF, Compressed Data: Host IF
Figure 46