MT9092AP Zarlink, MT9092AP Datasheet - Page 7

• Manufacturer Part Number: MT9092AP
• Description: Digital Telephone 44-Pin PLCC Tube
• Manufacturer: Zarlink

Specifications of MT9092AP

• Package: 44PLCC
• Power Supply Type: Analog
• Typical Supply Current: 8 mA
• Typical Operating Supply Voltage: 5 V
• Minimum Operating Supply Voltage: 4.75 V
• Maximum Operating Supply Voltage: 5.25 V

levels), the coefficients for tone and ringer generation (addresses 23h and 24h), and tone ringer warble rates
(address 26h). All undefined addresses below 20h are reserved for the temporary storage of interim variables
calculated during the execution of the DSP algorithms. These undefined addresses should not be written to via the
microprocessor port. The DSP can be programmed to execute the following micro-programs which are stored in
instruction ROM, (see PS0 to PS2, DSP Control Register, address 1Eh). All program execution begins at the frame
pulse boundary.
PS2
0
0
0
0
PS2
Note:
Power Up reset Program
A hardware power-up reset (pin 6, PWRST) will initialize the DSP hardware registers to the default values (all
zeros) and will reset the DSP program counter. The DSP will then be disabled and the PCM streams will pass
transparently through the DSP. The RAM-based registers are not reset by the PWRST pin but may be initialized to
their default settings by programming the DSP to execute the power up reset program. None of the micro-programs
actually require the execution of the power up reset program but it is useful for pre-setting the variables to a known
condition. Note that the reset program requires one full frame (125 µSec) for execution.
Gain Control Program
Gain control is performed on converted linear code for both the receive and the transmit PCM. Receive gain control
is set via the hardware register at address 1Dh (see bits B0 - B5) and may be changed at any time. Gain in 1.5 dB
increments is available within a range of +22.5 dB to -72 dB. Normal operation usually requires no more than a +20
to -20 dB range of control. However, the handsfree switching algorithm requires a large attenuation depth to
maintain stability in worst case environments, hence the large (-72 dB) negative limit. Transmit gain control is
divided into two RAM registers, one for setting the network level of transmit speech (address 20h) and the other for
setting the transmit level of DTMF tones into the network (address 21h). Both registers provide gain control in
1.5 dB increments and are encoded in the same manner as the receive gain control register (see address 1Dh, bits
B0 - B5). The power up reset program sets the default values such that the receive gain is set to -72.0 dB, the
transmit audio gain is set to 0.0 dB and the transmit DTMF gain is set to -3.0 dB (equivalent to a DTMF output level
of -4 dBm0 into the network).
1
1
1
1
PS1
PS1
0
0
1
1
0
0
1
1
Channels. Therefore, one of the B-Channel enable bits must be set (see Timing Control, address 15h : bits
CH
For the DSP to function it must be selected to operate, in conjunction with the Filter/Codec, in one of the B-
2
EN and CH
PS0
PS0
0
1
0
1
0
1
0
1
Power up reset program
Transmit and receive gain control program; with autonulling of the transmit PCM, if the
DTMF generation plus transmit and receive gain control program (autonull available via the
Tone ringer plus transmit and receive gain control program (autonull available via the AUTO
handsfree switching program
Last three selections reserved
AUTO bit is set (see address 1Dh)
AUTO control bit)
control bit)
3
EN).
Micro-program
Micro-program
Zarlink Semiconductor Inc.
MT9092
7
Data Sheet