Hayes Microcomputer Products RCV56HCF manual MDP Signal Definitions Contd

Models: RCV56HCF

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RCV56HCF PCI/CardBus Modem Designer’s Guide

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

O(DF)

Transmit Analog 1 and 2. The TXA1_L1 and TXA2_L1 outputs are differential outputs 180 degrees out of

TXA2_L1

 

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 μF.

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.

3-16

ROCKWELL PROPRIETARY INFORMATION

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Hayes Microcomputer Products RCV56HCF manual MDP Signal Definitions Contd, Pllgnd Connection. Connect to Agnd