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RCV56HCF PCI/CardBus Modem Designer’s Guide
ROCKWELL PROPRIETARY INFORMATION
1129
3-16
Table 3-4. MDP Signal Definitions (Cont'd)
Label I/O Type Signal Name/Description
TELEPHONE LINE/TELEPHONE/AUDIO INTERFACE SIGNALS AND REFERENCE VOLTAGE
TXA1_L1
TXA2_L1
O(DF)
Transmit Analog 1 and 2.
The TXA1_L1 and TXA2_L1 outputs are differential outputs 180 degrees out of
phase with each other. Each output can drive a 300
Ω
load.
RXA_L1 I(DA)
Receive Analog.
RXA_L1 is a single-ended receive data input from the telephone line interface or an optional
external hybrid circuit. The input impedance is > 70k
Ω
.
TELOUT_L1 O(DF)
Telephone Handset Analog Output.
TELOUT_L1 is a single-ended analog output to the telephone handset
speaker interface circuit. TELOUT_L1 can drive a 300
Ω
load.
TELIN_L1 I(DA)
Telephone Handset Analog Input.
TELIN_L1 is a single-ended analog input from the telephone handset
microphone interface circuit. The input impedance is > 70k
Ω
.
MIC_M I(DA)
Modem Microphone Input.
MIC_M is a single-ended microphone input. The input impedance is > 70k
Ω
.
MIC_V I(DA)
Voice Microphone Input.
MIC_V is a single-ended microphone input. The input impedance is > 70k
Ω
.
SPKROUT_M O(DF)
Modem Speaker Analog Output.
The SPKROUT_M analog output reflects the received analog input signal.
The SPKROUT_M on/off and three levels of attenuation are controlled by bits in DSP RAM. When the speaker
is turned off, the SPKROUT_M output is clamped to the voltage at the VC_L1 pin. The SPKROUT_M output
can drive an impedance as low as 300 ohms. In a typical application, the SPKROUT_M output is an input to
an external LM386 audio power amplifier.
VREF REF
High Voltage Reference.
Connect to VC_L1 through 10 µF (polarized, + terminal to VREF) and 0.1 µF
(ceramic) in parallel.
VC_L1 REF
Low Voltage Reference.
Connect to analog ground through 10 µF (polarized, + terminal to VC_L1) and
0.1 µF (ceramic) in parallel.
PLLVDD PLL
PLLVDD Connection.
Connect to VAA and to AGND through 0.1
µ
F.
PLLGND PLL
PLLGND Connection.
Connect to AGND.
MK4, MK5 IA
PLL Circuit Strap Option.
Connect MK4 to digital ground and leave MK5 open in order to enable the internal
PLL circuit.
SPKMD OA
Modem Speaker Digital Output.
The SPKMD digital output reflects the received analog input signal digitized
to TTL high or low level by an internal comparator to create a PC Card (PCMCIA)-compatible signal.