
PSB 7280
Semiconductor Group
160
Data Sheet 1998-07-01
This procedure is (nearly) identical with the interrupt handshake when in IOM/Host mode
(see
Chapter 6.2.3.2
) and the following steps are perfomed:
1. The JADE writes one frame of encoded audio data into the mailbox (most significant
byte first).
2.
The JADE generates a “VocoderFinished” interrupt at INT line to the host by writing a
value C0
H
or 80
H
(toggling) into IND interrupt status register at address 58
H
. The value
of this interrupt is each time toggling between C0
H
and 80
H
to ensure that a polling
host can consider a new “VocoderFinished”. For an interrupt driven host one should
just connect both numbers to the same interrupt service routine.
3. The host reads the compressed audio frame from the mailbox using the procedure
described in
Chapter 3.3.2.2
and may reset the INDB bit. The reset of the INDB bit is
not mandatory and may be skipped.
4. The host writes the compressed audio frame for the decoder into the mailbox using
the procedure described in
Chapter 3.3.2.2
.
5. The host generates an interrupt to the JADE by writing value 24
H
into INH interrupt
status register at address 50
H
.
6. The JADE reads the compressed audio data from the mailbox and acknowledges the
reception by resetting the INHB bit.
In the following, four 2.5 ms packets of uncompressed audio data are exchanged. See
Figure 47
for the handshake procedure: