MT90812 Mitel Networks Corporation, MT90812 Datasheet - Page 25

• Manufacturer Part Number: MT90812
• Description: Integrated Digital Switch (IDX)
• Manufacturer: Mitel Networks Corporation

Advance Information
6.4
A peak clipping indicator identifies the conference causing conference bridge overflow whenever a 14-bit two
complement overflow occurs
Conference Overflow bit in the Interrupt Status Register (INTS) is set and the conference ID is placed in the
Conference Overflow Status Register (CONFO). Refer to the CONFO register description on page 59.
Reading the Interrupt Status Register (INTS) will clear the Conference Overflow bit. A conference overflow will
not trigger an interrupt until the conference overflow bit is cleared. The conference overflow interrupt is
maskable using the Interrupt Enable Register (INTE). The conference interrupt mask does not disable updates
of the CONFO register. The Conference ID in this register will not be updated again until it is reset. The register
is reset following a read of the register or resetting the conference block or Mt90812 device.
Note 1 - The overflow limit is the same whether Ulaw or Alaw companding is used. Following gain adjustment
companding will then implement clipping to the Ulaw and Alaw max values of 8031 and 4032 respectively.
6.5
In order to initiate a conference, the Conference Party Control register as well as Connection Memory Low/
High must be programmed. Setting the ST bit for the first party programmed for a conference will remove any
other parties that may have been previously programmed for that conference. The following steps outline
initialization of a conference.
6.6
Setting the Conference ID number, in Conference Party Control register, to ‘0’ will disconnect the selected
channel from the conference. Once the selected channel is removed from the conference, the Output Enable
Conference Party Initialization
Conference Block Initialization
Conference Overflow
Starting a New Conference
Removing a channel from a Conference
1)
2)
3)
4)
5)
6)
7)
8)
9)
10) Enable the conference overflow interrupt if required, by setting CFE, bit 1 in the Interrupt Enable
Perform MT90812 reset or conference reset. The Conference Party Control registers are reset
Disable the conference overflow interrupt until after a conference is set up. Set CFE bit LOW in
Enable the conference block by writing to the conference control register, setting CFEN=1 and
Set up Tone Insertion: program the tone by writing the tone coefficient registers if a different
Write CMH with the Incoming gain, inversion bit and noise suppression for the first party.
Write CML with the Incoming channel DM address for the first party.
Write the Conference Party Control register with a conference ID from 1-5. Set the ST bit for the
Write CML of the Incoming channel with DM address of the conference output location (60-6E
Write CMH of the location with the required outgoing gain if it has not been previously set. Also
Repeat steps 5 to 8 for each additional party in the conference.
and all conference ID numbers are set to null.
the Interrupt Enable Register (INTE).
setting the tone duration.
programmable tone is required. Refer to “Tone Generation” on page 42 Identify the tone by
writing CML location 6F with the DM address of the Tone. Write CMH location 6F with the gain
setting for the insertion tone.
first party programmed for a conference. Setting the ST bit will remove any other parties that may
have been previously programmed for that conference. Set the Insertion Tone bit and outgoing
conference gain control required.
set the OE bit.
Register (INTE). Read the CONFO register to ensure it is reset allowing the next overflow to
update the conference ID value.
1
. Once a conference bridge overflow occurs an interrupt is asserted, the
MT90812
H
).
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