MT8880C Mitel Networks Corporation, MT8880C Datasheet - Page 9

• Manufacturer Part Number: MT8880C
• Description: Integrated DTMFTransceiver
• Manufacturer: Mitel Networks Corporation

BIT
b0
b1
b2
b3
RS0
0
0
1
1
Table 2. Internal Register Functions
CP/DTMF
NAME
TOUT
RSEL
IRQ
R/W
0
1
0
1
INTERRUPT ENABLE
REGISTER SELECT
MODE CONTROL
TONE OUTPUT
FUNCTION
Write to Transmit
Data Register
Read from Receive
Data Register
Write to Control
Register
Read from Status
Register
FUNCTION
Table 5. Control Register A Description
A logic ‘1’ enables the tone output. This function can be
implemented in either the burst mode or non-burst mode
In DTMF mode (logic ‘0’) the device is capable of generating
and receiving Dual Tone Multi-Frequency signals. When the
CP (Call Progress) mode is selected (logic ‘1’) a 6th order
bandpass filter is enabled to allow call progress tones to be
detected. Call progress tones which are within the specified
bandwidth
rectangular wave format if the IRQ bit has been enabled
(b2=1). Also, when the CP mode and BURST mode have both
been selected, the transmitter will issue DTMF signals with a
burst and pause of 102 ms (typ) duration. This signal duration
is twice that obtained from the DTMF transmitter if DTMF
mode had been selected. Note that DTMF signals cannot be
decoded when the CP mode of operation has been selected.
A logic ‘1’ enables the INTERRUPT mode. When this mode is
active and the DTMF mode has been selected (b1=0) the IRQ/
CP pin will pull to a logic ‘0’ condition when either 1) a valid
DTMF signal has been received and has been present for the
guard time duration or 2) the transmitter is ready for more data
(BURST mode only).
A logic ‘1’ selects Control Register B on the next Write cycle to
the Control Register address. Subsequent Write cycles to the
Control Register are directed back to Control Register A.
ISO
2
-CMOS
RSEL
will
C/R
b3
b3
be
presented
DESCRIPTION
MT8880C/MT8880C-1
S/D
IRQ
Table 3. CRA Bit Positions
Table 4. CRB Bit Positions
b2
b2
CP/DTMF
at
TEST
b1
b1
the IRQ/CP
BURST
TOUT
pin
b0
b0
.
in
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