PSB7238 SIEMENS [Siemens Semiconductor Group], PSB7238 Datasheet - Page 169

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

3. The JADE generates a “VocoderFinished” interrupt at INT line to the host by writing a
4. The host reads the compressed audio frame from the mailbox using the procedure
5. Start point in first frame
6. The host generates an interrupt to the JADE by writing value 24
7. The JADE reads the compressed audio data from the mailbox and acknowledges the
The JADE starts the above interrupt procedure once every frame (default: 10 ms),
except of the 16-kHz pass-through mode. In the 16-kHz pass-through mode the mailbox
cannot transfer the full data packet (320 or 336 bytes, depends on whether outband or
inband control is selected) at once. Only for this mode the above interrupt handshake
procedure is executed twice in one time frame. With the first “VocoderFinished”
256 bytes are transmitted in each direction, with the second run 64 bytes (outband
control) or 80 bytes (inband control) are transmitted.
The following steps are performed:
1. The JADE writes one frame of encoded audio data into the mailbox (most significant
2. The JADE writes a backup of the “VocoderFinished” interrupt number performed in the
When starting the above procedure, it begins at the point marked with “Start in first
frame”. This is to enable the host to have control of the real start time, so the host first
has to deliver compressed data to the JADE and generate the corresponding interrupt.
After that, the IOM/Host handshake procedure is executed cyclically.
1)
2)
Semiconductor Group
byte first).
next step into the host accessible register 61
missed interrupt when a slow host is connected, see text below.
value C0
of this interrupt is each time toggling between C0
host can consider a new “VocoderFinished”. For an interrupt driven host one should
just connect both numbers to the same interrupt service routine.
described in Section 3.3.2.2 and may reset the INDB bit. The reset of the INDB bit is
not mandatory and may be skipped.
The host writes the compressed audio frame for the decoder into the mailbox using
the procedure described in Section 3.3.2.2.
status register at address 50
reception by resetting the INHB bit.
To keep the interrupt load for the host as small as possible, the JADE does not generate an acknowledge
interrupt. It is guaranteed, that the INH interrupt 24
the interrupt 24
the next “VocoderFinished” from the JADE appears. So, in this case the host does not need to check the status
of INHB.
If the host wants to apply other actions, e.g. reading or writing of the control/status block, it has to wait for the
INHB bit to be reset to 0. All these additional actions should be completed within the current time frame (default:
within 10 ms after the “VocoderFinished” interrupt). Otherwise special situations in the interrupt sequence have
to be considered by the host, see text below.
H
or 80
H
soon enough, it is guaranteed, that the interrupt handshake procedure is completed before
H
(toggling) into IND interrupt status register at address 58
H
.
1) 2)
169
H
is serviced within a time of 125 s, so if the host sends
H
. This is only used for detection of a
H
and 80
H
to ensure that a polling
Data Sheet 1998-07-01
Firmware Features
H
into INH interrupt
H
PSB 7238
. The value